HK1192373A

HK1192373A - Non-linear polarized compound loop antenna

Info

Publication number: HK1192373A
Application number: HK14105550.5A
Authority: HK
Inventors: 福雷斯特．詹姆斯．布朗; 赖安．詹姆斯．奥尔西; 马修．罗伯特．福斯特
Original assignee: 多康公司
Priority date: 2011-01-18
Filing date: 2012-01-18
Publication date: 2014-08-15

Description

Circular polarization composite loop antenna

Cross Reference to Related Applications

This application claims priority from united states patent application number 13/008,835 filed on 18/1/2011, which is incorporated herein by reference in its entirety.

Technical Field

Embodiments provide single-sided and multilayer circularly polarized self-contained (circularly polarized) composite loop antennas (circularly polarized CPLs). Embodiments of the CPL antenna produce circularly polarized signals by using two electric field radiators that are physically oriented orthogonal to each other and by ensuring that the two electric field radiators are positioned such that an electrical delay between the two electric field radiators causes the two electric field radiators to emit their respective electric fields out of phase. Ensuring a proper electrical delay between the two electric field radiators maintains the high efficiency of the antenna and improves the axial ratio (axis ratio) of the antenna.

Statement regarding rights to invention under federally sponsored research and development

Not applicable.

Reference is made to a "sequence list", table or computer program listing attachment submitted on the compact disc.

Not applicable.

Background

The ever decreasing size of modern telecommunication devices creates a need for improved antenna designs. Known antennas in devices such as mobile/cellular telephones provide one of the main limitations in performance and are almost always a compromise in one way or another.

In particular, the efficiency of the antenna may have a major impact on the performance of the device. A more efficient antenna will radiate a higher proportion of the energy fed to it from the transmitter. Likewise, due to the inherent reciprocity of the antenna, a more efficient antenna will convert more received signals into electrical energy for processing by the receiver.

To ensure maximum transfer of energy (in both transmit and receive modes) between the transceiver (the device operating as both transmitter and receiver) and the antenna, the impedances of both should be matched in magnitude to each other. Any mismatch between the two will result in sub-optimal performance, where in transmit case energy is reflected back from the antenna to the transmitter. When operating as a receiver, the suboptimal performance of the antenna results in lower received power than would otherwise be possible.

Known simple loop antennas are usually current feeding devices that mainly generate a magnetic (H) field. As such, they are generally not suitable as conveyors. This is particularly true in the case of small loop antennas (i.e., those antennas that are less than one wavelength or have a diameter that is less than one wavelength). In contrast, voltage fed antennas such as dipoles generate both an electric (E) field and an H field, and can be used in both transmit and receive modes.

The amount of energy received by or transmitted from the loop antenna is determined in part by the area of the antenna. Generally, each time the area of the ring is halved, the amount of energy that can be received/transmitted is reduced by about 3dB depending on the application parameters such as initial size, frequency, etc. This physical constraint often means that it is practically impossible to use a very small loop antenna.

Composite antennas are those described below: in which Transverse Magnetic (TM) and Transverse Electric (TE) modes are excited to achieve higher performance benefits, such as higher bandwidth (lower Q), greater radiation intensity/power/gain, and greater efficiency.

In the late 40 s of the 20 th century, Wheeler and Chu first studied the characteristics of electrically short (ELS) antennas. Through their work, several numerical formulas were created to describe the limitations of antennas as they decrease in physical size. One of the limitations of ELS antennas mentioned by Wheeler and Chu that is particularly important is that they have a large radiation quality factor Q because they store more energy in time than the energy they radiate on average. According to Wheeler and Chu, ELS antennas have a high radiation Q, which results in minimal resistive losses in the antenna or matching network and results in very low radiation efficiencies, typically between 1% and 50%. As a result, since the 40's of the 20 th century, the scientific community has generally accepted ELS antennas with narrow bandwidths and poor radiation efficiency. Much of today's achievements in wireless communication systems utilizing ELS antennas come from rigorous experimentation and optimization of modulation schemes and over-the-air protocols, but ELS antennas commercially utilized today still reflect the narrow bandwidth, inefficient properties first established by Wheeler and Chu.

During the early 90 s of the 20 th century, Dale m.grimes and Craig a.grimes claimed that some combination of TM and TE modes operating together in ELS antennas, beyond the low radiation Q limit established by Wheeler and Chu theory, have been found mathematically. Grimes and Grimes describe their work in a journal entitled "Bandwidth and Q of Antennas Radiating TE and TM Modes" published in the IEEE conference on electromagnetic compatibility, 5.1995. These claims raise a lot of debate and have resulted in the term "composite field antenna" in which both TM and TE modes are excited, as opposed to "simple field antennas" which excite TM or TE modes alone. The benefits of composite field antennas have been demonstrated mathematically by several highly respected RF experts, including the panel of arms engagement by the american naval air war center, who summarized the evidence of lower radiation Q than the Wheeler-Chu limit, increasing radiation intensity, directivity (gain), radiation power, and radiation efficiency (p.l. overfelt, d.r. bowling, d.j.white, "colorful Magnetic Loop, Electric diode Array Antenna (Preliminary Results) (collocated Magnetic Loop, Electric Dipole Array Antenna (Preliminary Results)", provisional report, 9 months 1994).

Composite field antennas have proven to be complex and difficult to physically implement due to the unwanted element coupling effects and the associated difficulty of designing low loss passive networks to combine electric and magnetic radiators.

There are a number of examples of two-dimensional non-composite antennas that typically include printed metal strips on a circuit board. However, these antennas are voltage fed. An example of one such antenna is a Planar Inverted F Antenna (PIFA). Most similar antenna designs also primarily include quarter-wave (or some multiple of a quarter-wave) voltage-fed dipole antennas.

Planar antennas are also known in the art. For example, U.S. patent 5,061,938 to Zahn et al requires an expensive teflon substrate or similar material for antenna operation. United states patent 5,376,942 to Shiga teaches a planar antenna that can receive but not transmit microwave signals. The Shiga antenna also requires an expensive semiconductor substrate. U.S. patent 6,677,901 to Nalbandian relates to the following planar antenna: it requires a substrate with a ratio of permittivity to permeability (permeability) of 1:1 to 1:3 and is only capable of operating in the HF and VHF frequency ranges (3 MHz to 30MHz and 30MHz to 300 MHz). Although it is known to print some lower frequency devices on inexpensive glass reinforced epoxy laminates such as FR-4 commonly used for ordinary printed circuit boards, the dielectric loss of FR-4 is considered too high and the dielectric constant is not sufficiently tightly controlled with respect to such substrates for use at microwave frequencies. For these reasons, alumina substrates are more commonly used. In addition, none of these planar antennas are composite loop antennas.

The basis for the improved performance in terms of bandwidth, efficiency, gain and radiation intensity of a composite field antenna comes from the influence of the energy stored in the near field of the antenna. In RF antenna design, it is desirable to convert as much energy presented to the antenna into radiated energy as possible. The energy stored in the near field of the antenna has historically been referred to as reactive power and is used to limit the amount of power that can be radiated. In discussing complex power, there is a real and imaginary part (often referred to as the "reactive" part). Real power leaves the source and never returns, while imaginary or reactive power tends to oscillate around a fixed position of the source (within half a wavelength) and interact with the source, affecting the operation of the antenna. The presence of real power from multiple sources is directly additive, while multiple sources of imaginary power can be additive or subtractive (subtractive). The benefit of the composite antenna is that it is driven by both TM (electric dipole) and TE (magnetic dipole) sources, which allows engineers to create designs that take advantage of reactive power cancellation previously unavailable in simple field antennas, thereby improving the real power transfer characteristics of the antenna.

In order to be able to cancel reactive power in a composite antenna, it is necessary that the electric and magnetic fields operate orthogonally to each other. While a large number of arrangements of electric field radiators required to emit an electric field and magnetic loops required to generate a magnetic field have been proposed, all such designs have fixedly chosen three-dimensional antennas. For example, U.S. patent 7,215,292 to McLean requires a pair of magnetic rings in parallel planes with an electric dipole located on a third parallel plane between the pair of magnetic rings. U.S. patent 6,437,750 to Grimes et al requires two pairs of magnetic rings and electric dipoles that are physically arranged orthogonal to each other. U.S. patent application US2007/0080878 filed by McLean teaches an arrangement where the magnetic and electric dipoles are also in orthogonal planes.

Commonly owned U.S. patent application No. 12/878,016 teaches a linearly polarized multilayer planar composite loop antenna. Commonly owned U.S. patent application No. 12/878,018 teaches a linearly polarized single-sided composite loop antenna. Finally, commonly owned U.S. patent application No. 12/878,020 teaches a linearly polarized self-contained composite loop antenna. These commonly owned patent applications differ from prior art antennas in that: they are composite loop antennas having one or more magnetic loops and one or more electric field radiators physically arranged in two dimensions, without the need for a three-dimensional arrangement of magnetic loops and electric field radiators as in the antenna designs of McLean and Grimes et al.

Drawings

FIG. 1A is a plan view of a single-sided 2.4GHz self-contained circularly polarized composite loop antenna, according to one embodiment;

FIG. 1B shows the 2.4GHz antenna of FIG. 1A with right-hand circularly polarized signals propagating in the positive z-direction and left-hand circularly polarized signals propagating in the negative z-direction;

FIG. 2A is a plan view of a single-sided 402MHz self-contained circularly polarized composite loop antenna having two electric field radiators positioned along two different points of minimum reflected current, according to one embodiment;

FIG. 2B is a graph illustrating the return loss of the single-sided 402MHz antenna of FIG. 2A;

FIG. 3 is a plan view of an embodiment of a single-sided 402MHz self-contained circularly polarized composite loop antenna using two delay loops;

fig. 4 is a plan view of one side of an embodiment of a two-sided 402MHz self-contained circularly polarized composite loop antenna using one electric field radiator and a patch on the back of the antenna that acts as a second electric field radiator;

fig. 5 is a plan view of one side of an embodiment of a two-sided 402MHz, self-contained, circularly polarized composite loop antenna using one electric field radiator, a patch on the back of the antenna that acts as a second electric field radiator, and a combination of a delay ring and delay stub (stub);

fig. 6 is a plan view of one side of an embodiment of a two-sided 402MHz self-contained circularly polarized composite loop antenna that uses three delay stubs to adjust the delay between the electric field radiator and a backside patch on the back of the antenna that acts as a second electric field radiator; and

fig. 7 is a plan view of one side of an embodiment of a double-sided 402MHz, self-contained, circularly polarized composite loop antenna having an electric field radiator with an electrically extended electric field radiator, a backside patch on the back of the antenna that serves as a second electric field radiator, a delay loop that is generally arcuate in shape, and a delay stub.

Detailed Description

Embodiments provide single-sided and multi-layer circularly polarized self-contained composite loop antennas (circularly polarized CPL antennas). Embodiments of a circularly polarized CPL antenna generate circularly polarized signals by using two electric field radiators physically oriented orthogonal to each other and by ensuring that the two electric field radiators are positioned such that an electrical delay between the two electric field radiators causes the two electric field radiators to emit their respective electric fields out of phase. Ensuring a proper electrical delay between the two electric field radiators also maintains the high efficiency of the antenna and it improves the axial ratio of the antenna.

Single-sided, multilayer, and self-contained composite loop antennas are discussed in united states patent applications No. 12/878,016, No. 12/878,018, and No. 12/878,020, which are incorporated herein by reference in their entirety.

Circular polarization refers to the phenomenon in which an electric field and a magnetic field continuously rotate while maintaining their respective orthogonality when an electromagnetic wave generated by an antenna propagates through space away from the antenna. Circular polarization can penetrate moisture and obstacles better than linear polarization. This makes circular polarization suitable for wet environments, metropolitan areas with many buildings and trees, and satellite applications.

For a linearly polarized antenna, the transmitter and receiver of the separate device must have similar orientations so that the receiver can receive the strongest signal from the transmitter. For example, if the transmitter is oriented vertically, the receiver should also be oriented vertically to receive the strongest signal. On the other hand, if the transmitter is oriented vertically and the receiver is slightly skewed or tilted at an angle other than vertical, the receiver will receive weaker signals. Similarly, if the transmitter is skewed at an angle and the receiver is vertical, the receiver will receive a weaker signal. This can be a significant problem for certain types of mobile devices, such as cellular-based phones, where the receiver in the phone may have a constantly changing orientation, or where the phone orientation with the best signal strength is also the most uncomfortable phone orientation for the user. Therefore, when designing an antenna to be used in a portable electronic device or for a satellite receiver, the orientation of the receiving device cannot be predicted, which therefore leads to performance degradation of the receiver. In the case of a portable electronic device, the orientation of the receiver must change unpredictably depending on what the user is doing while using the portable electronic device.

A possible solution to this problem is to use multiple receivers or multiple transmitters arranged in different orientations, thereby improving the quality of the signal received by the receivers. For example, a first receiver may be vertical, a second receiver may be oriented at a 45 degree angle, and a third receiver may be horizontal. This will enable the receiver to receive the following signals: a linearly vertically polarized signal, a linearly horizontally polarized signal, and a linearly polarized signal at an angle. In this case, when the signal transmitted from the transmitter matches the orientation of one of the receivers, the receiver may receive the strongest signal. However, the use of multiple receivers/transmitters requires a larger receiving/transmitting device to accommodate the multiple receivers/transmitters. In addition, the benefits of multiple receivers/transmitters are offset by the power consumption required to power additional receivers/transmitters.

In circular polarization, the transmitter and receiver do not have to be similarly oriented, as the propagating signal is constantly rotating itself. Thus, the receiver will receive the same signal strength regardless of the orientation of the receiver. As noted above, in circular polarization, as the electric and magnetic fields propagate through space, the electric and magnetic fields constantly rotate while maintaining their respective orthogonality.

Fig. 1A shows an embodiment of a single-sided 2.4GHz circularly polarized CPL antenna 100 having a length of about 2.92 centimeters and a height of about 2.92 centimeters. Although specific dimensions are noted for this antenna design and other embodiments disclosed herein, it should be understood that the invention is not limited to specific dimensions or operating frequencies and that antennas using different dimensions, frequencies, components, and operating characteristics may be developed without departing from the teachings of the invention.

Antenna 100 includes a magnetic loop 102, a first electric field radiator 104 directly coupled to magnetic loop 102, and a second electric field radiator 106 orthogonal to first electric field radiator 104. Both the electric field radiator 102 and the electric field radiator 104 are physically located inside the magnetic loop 102. The electric field radiators 104 and 106 are preferably located inside the magnetic loop 102 for maximum antenna performance, although the electric field radiators 104 and 106 may also be located outside the magnetic loop. Both the first and second electric field radiators 104 and 106 are quarter-wavelength monopoles, but alternative embodiments may use monopoles that are some multiple of a quarter-wavelength.

The composite loop antenna is capable of operating in both a transmit mode and a receive mode, thereby enabling better performance than known loop antennas. The two basic components of a CPL antenna are a magnetic loop that generates a magnetic field (H-field) and an electric field radiator that emits an electric field (E-field). The H-field and the E-field must be orthogonal to each other to enable the electromagnetic wave emitted by the antenna to propagate efficiently through space. To achieve this effect, the electric field radiator is positioned at either an approximately 90 degree electrical position or an approximately 270 degree electrical position along the magnetic loop. Orthogonality of the H and E fields may also be achieved by positioning the electric field radiator along the magnetic loop at a point where current flowing through the magnetic loop is at a minimum of reflection. The point along the magnetic loop of the CPL antenna at which the current is at a minimum reflection depends on the geometry of the magnetic loop. For example, the point at which the current is at a minimum of reflection may be initially identified as a first region of the magnetic loop. After adding or removing metal to the magnetic loop to achieve impedance matching, the point at which the current is at a minimum of reflection may be changed from the first region to the second region.

Returning to fig. 1A, the electric field radiators 104 and 106 may be coupled to the magnetic loop 102 at the same 90 or 270 degree connection point or at the same connection point where the current flowing through the magnetic loop 102 is at a minimum of reflection. Alternatively, the first electric field radiator may be positioned along the magnetic loop at a first point where current is at a minimum of reflection, and the second electric field radiator may be positioned along the magnetic loop at a different point where current is also at a minimum of reflection. The electric field radiator is not necessarily directly coupled to the magnetic loop. Alternatively, each of the electric field radiators may be connected to the magnetic loop 102 using a narrow electrical trace to increase the inductive delay (INDUCTIVEDELAY). In particular, when the electric field radiator is placed within the magnetic loop, care must be taken to ensure that the radiator is not electrically coupled to other portions of the antenna (such as transition 108 or counterpoise 110, described further below), which can disrupt the performance or operability of the antenna unless some form of coupling is desired, as described further below.

As indicated, the antenna 100 includes a transition 108 to the first and second electric field radiators 104 and 106 and a counterpoise 110. Transition piece 108 includes a portion of magnetic ring 102 having a width greater than a width of magnetic ring 102. The function of transition piece 108 is described further below. The built-in counterpoise 110 allows the antenna 100 to be completely independent of any ground plane or chassis of the product in which the antenna is used. Embodiments of the antenna 100, and similarly alternative embodiments of circularly polarized CPL antennas, do not necessarily include a transition piece and/or counterpoise.

The transition piece partially delays the voltage distribution around the magnetic loop and sets the impedance of the counterpoise so that the voltages present in the magnetic loop and the transition piece do not cancel the voltage emitted by the electric field radiator. When the counterpoise and the electric field radiator are positioned 180 degrees out of phase with each other in the antenna, the gain of the antenna can be increased regardless of any ground plane nearby. It should also be understood that the transition piece may be adjusted in length and width to match the voltage present in the counterpoise.

The antenna 100 also includes a balun (balun) 112. A balun is an electrical converter that can convert an electrical signal balanced with respect to ground (differential) into an unbalanced (single-ended) signal or vice versa. In particular, the balun presents a high impedance to common mode signals and a low impedance to differential mode signals. The balun 112 functions to cancel the common mode current. In addition, balun 112 adjusts antenna 100 to the desired input impedance and adjusts the impedance of the entire magnetic loop 102. The balun 112 is generally triangular in shape and includes two portions divided by a mid-gap 114. Alternative embodiments of the antenna 100, and similarly of the self-contained CPL antenna and the circularly polarized CPL antenna, do not necessarily include baluns.

The length of the transition piece 108 may be set based on the operating frequency of the antenna. For higher frequency antennas with shorter wavelengths, a shorter transition piece may be used. On the other hand, for lower frequency antennas with longer wavelengths, a longer transition piece 108 may be used. The transition piece 108 may be adjusted independently of the counterpoise 110.

The counterpoise 110 is referred to as being built-in because the counterpoise 110 is formed by the magnetic ring 102. Thus, the self-contained counterpoise antenna does not require a ground plane to be provided by the device using the antenna. The length of the counterpoise 110 may be adjusted as needed to achieve the desired antenna performance.

In the case of a simple quarter-wave monopole, the ground plane and the counterpoise are one and the same. However, the ground plane and the counterpoise do not necessarily need to be the same. The ground plane is where the reference phase point is located, and the counterpoise is what sets the far field polarization. In the case of a self-contained CPL antenna, the transition piece is used to create a 180 degree phase delay to the counterpoise that also moves the reference phase point corresponding to ground into the counterpoise, so that the antenna is independent of the device connected to the antenna. If a balun is included at the ends of the magnetic loop, then both ends of the magnetic loop are the grounds of the antenna. If the antenna does not include a counterpoise, the portion of the magnetic loop approximately 180 degrees from the electric field radiator will still act as a ground plane.

Embodiments of the antenna 100 are not limited to including the transition piece 108 and/or the counterpoise 110. Thus, the antenna 100 may not include the transition piece 108, but still include the counterpoise 110. Alternatively, the antenna 100 may not include the transition piece 108 or the counterpoise 110. If the antenna 100 does not include the counterpoise 110, the gain and efficiency of the antenna 100 will be slightly degraded. If the antenna 100 does not include a counterpoise, the electric field radiator will still look approximately 180 degrees from the electric field radiator for a counterpoise, such as a metal sheet that may be used as a counterpoise (e.g., the left side of the magnetic loop 102 of FIG. 1A). While the left side of magnetic ring 102 (without the counterpoise) may operate in a similar manner, it may not be as effective (due to its reduced width) as counterpoise 110, which has a width greater than the width of magnetic ring 102. In other words, anything connected to the point of minimum reflected current along the magnetic loop will look for the counterpoise 180 degrees from the point of minimum reflected current. In the antenna 100, the counterpoise 110 is positioned approximately 180 degrees from the point of minimum reflected current for both electric field radiators 104 and 106. However, as noted above, despite the benefits of the counterpoise 110, removing the counterpoise 110 will have only marginal effects on the gain and performance of the antenna 100.

Although fig. 1A shows a plan view of the antenna 100 with the first electric field radiator oriented horizontally and the second electric field radiator oriented vertically, in some embodiments, the electric field radiators may be oriented along different angles on the same plane. Although the precise location of the two electric field radiators may vary, it is important that the two electric field radiators be positioned orthogonally to each other for the antenna 100 to operate as a circularly polarized CPL antenna. For example, the first electric field radiator may be tilted at a 45 degree angle, with the electrical trace coupling the tilted first electric field radiator to the magnetic loop. The second electric field radiator need only be orthogonal to the first electric field radiator to enable the antenna to produce a circularly polarised signal. In such an embodiment, the general cross shape formed by the two intersecting electric field radiators will be inclined by 45 degrees.

The circularly polarized CPL antenna 100 is planar. Thus, Right Hand Circular Polarization (RHCP) is transmitted in the positive z direction in a first direction perpendicular to the plane formed by the antenna 100. Left Hand Circular Polarization (LHCP) is transmitted in the negative z-direction in a second direction opposite to the first direction. Fig. 1B shows RHCP120 radiating from the front of antenna 100 and LHCP122 radiating from the back of antenna 100.

At lower frequencies, arranging the second electric field radiator orthogonal to the second electric field may not work if there is not sufficient delay between the first and second electric field radiators. If there is not sufficient delay between the two electric field radiators, the two electric field radiators may emit their respective electric fields simultaneously or not sufficiently out of phase, resulting in cancellation of their electric fields. Electric field cancellation results in lower efficiency and gain of the antenna because less electric field is radiated into space. This may also result in a cross-polarized antenna rather than a circularly polarized antenna.

As a solution, referring back to fig. 1A, the two electric field radiators can be positioned along different points of the magnetic loop. Thus, the second electric field radiator 106 need not be positioned on top of the first electric field radiator 104. For example, one of the electric field radiators may be positioned at a 90 degree phase point, while the second electric field radiator may be positioned at a 270 degree phase point. As noted above, a magnetic loop in a CPL antenna may have a plurality of points along the magnetic loop where the current is at a minimum of reflection. Thus, one of the electric field radiators may be positioned at a first point where the current is at a minimum of reflection, and the second electric field radiator may be positioned at a second point where the current is also at a minimum of reflection.

In the antenna 100 of fig. 1A, both electric field radiators 104 and 106 are connected at the same reflection minimum point. However, in an alternative embodiment of antenna 100, as shown in fig. 2A, first electric field radiator 104 may be connected to a first point along magnetic loop 102 and second electric field radiator 106 may be connected to a second point along magnetic loop 102. However, as noted above, as also shown in fig. 2A, the two electric field radiators would still need to be positioned orthogonally with respect to each other for the antenna to have circular polarization, even if not in physical contact with each other.

In the antenna 100 of fig. 1A, operating at a frequency of 2.4GHz, the distance 105 between the first electric field radiator 104 and the second electric field radiator 106 is long enough to ensure that the first electric field radiator 104 is out of phase with the second electric field radiator 106. In the antenna 100, the center point 107 is a feeding point of the second electric field radiator.

In antenna 100, current flows into antenna 100 via the right half of balun 112, flows along magnetic loop 102, flows into first electric field radiator 104, flows into second electric field radiator 106, flows through transition piece 108, flows through counterpoise 110 and flows out through the left side of balun 112.

Fig. 2A shows an embodiment of a single-sided 402MHz self-contained circularly polarized CPL antenna 200. The antenna 200 includes two electric field radiators 204 and 206 positioned along two different reflective minimum points. The 402MHz antenna 200 has a length of approximately 15 centimeters and a height of approximately 15 centimeters. The antenna 200 does not include a transition piece, but it includes a counterpoise 208. The counterpoise 208 spans the length of the left side of the magnetic ring 202 and has a width that is twice the width of the magnetic ring 202. However, these dimensions are not fixed, and the length and width of the counterpoise may be adjusted to maximize the gain and performance of the antenna. The antenna 200 also includes a balun 210, even though alternative embodiments of the antenna 200 do not necessarily include a balun 210. In the antenna 200, the balun 210 is physically located inside the magnetic loop 202. However, the balun 210 may also be physically located outside of the magnetic loop 202.

In the antenna 200, current flows into the antenna 200 at the feed point 216 via the right half of the balun 210. Then, the current flows rightward along the magnetic ring 202. The first electric field radiator 204 is positioned along the bottom half of the magnetic loop 202 to the right of the balun 210. Current flows into the first electric field radiator 204 and along the entire length of the first electric field radiator 204, continuing along the magnetic loop 202 and flowing through the delay loop 212. The current then flows through the entire length of the second electric field radiator 206 and continues to flow through the top side of the magnetic loop 202, through the counterpoise 208 and into the delay stub 214, and so on.

As noted, the antenna 200 includes a small delay loop 212 protruding into the magnetic loop 202. The delay loop 212 is used to adjust the delay between the first electric field radiator 204 and the second electric field radiator 206. The first electric field radiator 204 is positioned at the 90 degree phase point and the second electric field radiator 206 is positioned at the 180 degree phase point. The two electric field radiators 204 and 206 are of the same width. The width and length of the two electric field radiators 204 and 206 can be varied to adjust the operating frequency of the antenna and to adjust the axial ratio of the antenna.

Axial ratio is the ratio of the orthogonal components of the electric field. A circularly polarized field consists of two orthogonal electric field components of equal magnitude. For example, if the magnitudes of the electric field components are not equal or nearly equal, the result is an elliptically polarized field. The axial ratio is calculated by obtaining a logarithm (log) of the first electric field in one direction divided by a second electric field orthogonal to the first electric field. In a circularly polarized antenna, it is desirable to minimize the axial ratio.

The length and width of the delay loop 212 and the thickness of the traces making up the delay loop 212 can be adjusted as needed to achieve the necessary delay between the two electric field radiators. Having the delay loop 212 protrude into the magnetic loop 202, i.e., positioned inside the magnetic loop 202, optimizes the axial ratio of the antenna 200. However, the delay ring 212 may also protrude out of the magnetic ring 202. In other words, the delay loop 212 increases the electrical length between the first electric field radiator 204 and the second electric field radiator 206. The delay ring 212 need not be substantially rectangular in shape. Embodiments of the delay loop 212 may be curved, zigzag shaped, or any other shape that may substantially slow the flow of electrons along the delay loop 212, thereby ensuring that the electric field radiators are out of phase with each other.

One or more delay loops may be added to the antenna to achieve an appropriate delay between the two electric field radiators. For example, fig. 2A shows an antenna 200 with a single delay loop 212. However, alternative embodiments of the antenna 200 may have two or more delay loops instead of a single delay loop 212.

Antenna 200 also includes stub 214 on the left side of magnetic loop 202. Stub 214 is directly coupled to magnetic loop 202. The stub 214 is capacitively coupled to the second electric field radiator 206 to electrically elongate the electric field radiator 206 to adjust impedance matching to a frequency band. In the antenna 200, the second electric field radiator 206 may not be made physically longer, as extending the electric field radiator 206 in this manner would capacitively couple the electric field radiator 206 to the counterpoise 208, thereby degrading the performance of the antenna.

As noted above, the second electric field radiator 206 would normally need to be longer than shown in fig. 2A, as shown in fig. 2A. Specifically, the second electric field radiator 206 would have to be longer by the same length as the stub 214. However, if the electric field radiator 206 is made longer, the electric field radiator 206 will capacitively couple to the left side of the magnetic loop 202. The use of the stub enables the second electric field radiator 206 to be seen as electrically long. The electrical length of the electric field radiator 206 can be adjusted by moving the stub 214 up and down the left side of the magnetic loop 202. Moving the stub 214 higher along the left side of the magnetic loop 202 results in an electrically longer electric field radiator 206. On the other hand, moving the stub 214 lower along the left side of the magnetic loop 202 results in the electric field radiator 206 appearing electrically shorter. The electrical length of the electric field radiator 206 can also be adjusted by changing the physical dimensions of the stub 214.

Fig. 2B is a graph showing the return loss of the antenna 200 without the stub 214. Thus, fig. 2B shows the return loss of the antenna 200 with two electric field radiators of different electrical lengths. When the two electric field radiators have different electrical lengths, the return loss shows two dips (dip) at different frequencies. The first and second dips 220, 222 correspond to frequencies at which the impedance of the antenna is matched. Each electric field radiator produces its own resonance. Each resonance produces a respective plurality of dips in return loss. In the antenna 200, the first electric field radiator 204 produces a slightly higher resonance corresponding to the second dip 222 than the second electric field radiator 206 because of the proximity of the first electric field radiator 204 to the feed point 216 along the magnetic loop 202. On the other hand, because of the longer length between the feed point 216 and the second electric field radiator 206, the second electric field radiator 206 produces a lower resonance corresponding to the first dip 220. As mentioned above, the stub 214 electrically elongates the second electric field radiator 206. This therefore moves the first drop 220 and causes the first drop 220 to match the second drop 222.

Fig. 3 is a plan view showing an alternative embodiment of a single-sided 402MHz self-contained circularly polarized antenna 300 having two delay loops. The antenna 300 has a length of approximately 15 centimeters and a height of approximately 15 centimeters. The antenna 300 includes a magnetic loop 302, a first electric field radiator 304 positioned along a first point where current is at a minimum of reflection, and a second electric field radiator 306 positioned along a second point where current is at a minimum of reflection. The antenna 300 also includes a counterpoise 308 and a balun 310. In contrast to the antenna 200 of fig. 2A, the antenna 300 does not include the stub 214, but includes two delay loops, a first delay loop 312 along the right side of the magnetic loop 302 and a second delay loop 314 along the right side of the magnetic loop 302. The second delay loop 314 is used to adjust the electrical delay between the two electric field radiators 304 and 306. In the antenna 300, the top 316 of the second delay loop 314 is capacitively coupled to the second electric field radiator 306 to perform a similar function to the stub 214 in the antenna 200 by electrically lengthening the second electric field radiator 306.

When the antenna includes two or more delay loops, the two or more delay loops do not necessarily have the same size. For example, in the antenna 300, the first delay loop 312 is almost half as small as the second delay loop 314. Alternatively, the second delay loop 314 may be replaced by two smaller delay loops. Delay loops may be added to either side of the magnetic loop and a single antenna may have delay loops on one or more sides of the magnetic loop.

A suitable delay between the two electric field radiators can be achieved by increasing the overall length of the magnetic loop without using a delay loop. Thus, if the delay loops 312 and 314 are not included, the magnetic loop 302 would have to be larger to ensure the proper delay between the first electric field radiator 304 and the second electric field radiator 306. Thus, the use of a delay loop may be used as a space saving technique during antenna design, i.e., the overall size of the antenna may be reduced by moving the various components to physical locations inside the magnetic loop 302.

Fig. 2A and 3 are examples of an antenna having a magnetic loop with its angle cut at about a 45 degree angle. Cutting the corners of the magnetic loop at an angle improves the efficiency of the antenna. Having the magnetic ring at an angle forming an approximately 90 degree angle affects the flow of current through the magnetic ring. When the current flowing through the magnetic ring hits (hit) an angle of 90 degrees, this causes the current to bounce (ricochet), where the reflected current flows against the main current or forms a vortex pool (eddy pool). Energy consumption as a result of the 90 degree angle can negatively impact antenna performance, most notably in smaller antenna implementations. Cutting the corners of the magnetic ring at approximately a 45 degree angle improves the flow of current around the corners of the magnetic ring. Thus, the angled angle causes electrons in the current to be less impeded as they flow through the magnetic loop. While cutting the angle at a 45 degree angle is preferred, alternative embodiments are possible where the cut is made at an angle other than 45 degrees. Any CPL antenna may have a magnetic loop with an angle cut away at an angle to improve antenna performance, but the cut angle is not always necessary.

Instead of using loops to adjust the delay between two electric field radiators in an antenna, one or more substantially rectangular metal stubs may be used to adjust the delay between two electric field radiators. Fig. 4 shows an embodiment of a double-sided (multi-layer) 402MHz self-contained circularly polarized antenna 400. Antenna 400 includes a magnetic loop 402, a first electric field radiator 404 (vertical), a second electric field radiator 406 (horizontal), a transition piece 408, a counterpoise 410, and a balun 412.

The first electric field radiator 406 is attached to a square patch 414 that electrically extends the first electric field radiator 406. The square patch 414 is directly coupled to the magnetic loop 402. The size of the square patch 414 may be adjusted accordingly based on how the electric field radiator 406 is adjusted. The antenna 400 also includes a backside patch 416 located on the backside of the substrate to which the antenna is applied. Specifically, the back patch 416 spans the entire length of the left side of the magnetic ring 402. The back patch 416 radiates vertically along with the first electric field radiator 404 and out of phase with the second electric field radiator 406. The back patch 416 is not electrically connected to the magnetic loop, and as such, is a parasitic electric field radiator. Thus, the antenna 400 is an example of a circularly polarized CPL antenna having two vertical elements as electric field radiators and only one horizontal element as a first electric field radiator. Other embodiments may include many different combinations of vertical elements operating together and many different combinations of horizontal elements operating together, and so long as the vertical and horizontal elements are out of phase as described herein, the antenna will be circularly polarized.

The antenna 400 also includes a first delay stub 418 and a second delay stub 420. The two delay stubs 418 and 420 are substantially rectangular in shape. The delay stubs 418 and 420 serve to adjust a delay between the first electric field radiator 404 and the second electric field radiator 406. Although fig. 4 shows two delay stubs 418 and 420 protruding into the magnetic loop 402, alternatively, the two delay stubs 418 and 420 may be arranged such that the two delay stubs 418 and 420 protrude out of the magnetic loop 402.

Fig. 5 shows another embodiment of a dual-sided 402MHz self-contained circularly polarized CPL antenna 500. In contrast to other antennas described so far, the antenna 500 includes a magnetic loop 502 and only one electric field radiator 504. The antenna 500 uses a large metal back patch 506 on the back of the antenna 500 as a parasitic vertical electric field radiator rather than using a second electric field radiator. The back patch 506 has a generally rectangular cutout 508, with the portion 508 being cut out of the back patch 506 to reduce capacitive coupling between the electric field radiator 504 and the back patch 506. The cutout 508 does not affect the radiation pattern emitted by the backside patch 506. The antenna 500 also includes a transition piece 510, a counterpoise 512, and a balun 514.

In particular, the antenna 500 shows the use of a combination of delay loops, delay stubs, and metal patches to adjust the delay between the electric field radiator 504 and the backside patch 506. The delay loop 516 does not radiate and is used to adjust the delay between the electric field radiator 504 and the backside patch 506. The delay ring 516 also has its corners cut off at an angle. As mentioned above, cutting the corners at an angle may improve the flow of current around the corner.

The antenna 500 also includes a metal patch 518 that is directly coupled to the magnetic loop 502, and a smaller delay stub 520 that is also directly coupled to the magnetic loop 502. Both the metal patch 518 and the delay stub 520 help to adjust the delay between the electric field radiator 504 and the backside patch 506, which is a vertical radiator. The metal patch 518 has its bottom left corner cut away to reduce the capacitive coupling between the metal patch 518 and the delay loop 516.

The backside patch 506, even if parasitic, is positioned in a direction orthogonal to the electric field radiator 504. For example, if the electric field radiator 504 is oriented at an angle and coupled to the magnetic loop 502 via electrical traces, the backside patch 506 would have to be oriented such that the difference in orientation between the electric field radiator 504 and the backside patch 506 is 90 degrees.

Fig. 6 shows another example of a two-sided 402MHz self-contained circularly polarized CPL antenna 600. The antenna 600 includes a magnetic loop 602, an electric field radiator 604, a backside patch 606 as a second parasitic radiator orthogonal to the electric field radiator 604, a transition 608, a counterpoise 610, and a balun 612. Fig. 6 is an example of an antenna 600 that uses only delay stubs to adjust the delay between the electric field radiator 604 and the backside patch 606. The backside patch 606 is located on the backside of the antenna 600. The back antenna 606 spans the entire length of the left side of the magnetic loop 602. The backside antenna 606 does not have a cut-away portion as is the case with the backside patch 506 according to fig. 5, because the backside patch 606 is narrow.

The antenna 600 utilizes three delay stubs to adjust the delay between the electric field radiator 604 and the backside patch 606. Fig. 6 includes a large delay stub 614 positioned to the right of the balun 612, a medium delay stub 616 positioned along the right side of the magnetic loop 602 and in front of the electric field radiator 604, and a small delay stub 618 also positioned along the right side of the magnetic loop 602 but behind the electric field radiator 604.

As noted above, the self-contained circularly polarized CPL antenna may use only a delay loop, only a delay stub, or a combination of a delay loop and a delay stub to adjust the delay between the two electric field radiators or between the electric field radiator and other elements as the second electric field radiator. The antenna may use one or more delay loops of different sizes. Additionally, some of the delay rings may have their corners cut off at an angle to improve the flow of current along the corners of the delay rings. Similarly, the antenna may use one or more delay stubs of different sizes. The delay stubs may also be shaped or cut accordingly to reduce capacitive coupling with other elements in the antenna. Finally, both the delay ring and the delay stub may be physically located inside the magnetic ring such that they protrude into the magnetic ring. Alternatively, the delay ring and the delay stub may be physically located outside the magnetic ring such that they protrude out of the magnetic ring. A single antenna may also combine one or more delay loops/stubs that protrude into the magnetic loop or one or more delay loops/stubs that protrude out of the magnetic loop. The delay ring may have various shapes ranging from a substantially rectangular shape to a substantially smooth curved shape.

Fig. 7 shows another example of a two-sided 402MHz self-contained circularly polarized CPL antenna 700. The antenna 700 includes a magnetic loop 702, an electric field radiator 704 having a small trace 706 in the middle of the electric field radiator 704, a backside patch 708 that is a parasitic electric field radiator orthogonal to the electric field radiator 704, a transition 710, a counterpoise 712, and a balun 714. The small trace 702 is positioned orthogonal to the electric field radiator 704 and serves the purpose of electrically extending the electric field radiator 704 for impedance adjustment. Thus, the small trace 706 orthogonal to the electric field radiator 704 extends the electric field radiator 704 without having to make the electric field radiator physically longer, rather than making the electric field radiator 704 longer and having to cut away a portion of the backside patch 708 to prevent capacitive coupling between the two elements.

The antenna 700 is an example of an antenna using a delay loop having a substantially smooth curve shape. Delay ring 716 is generally arcuate. It should be noted, however, that the use of a rectangular delay loop improves the performance of the antenna over the use of an arcuate loop as shown in fig. 7.

The antenna 700 also includes a delay stub 718 that is generally rectangular in shape. Both the delay loop 716 and the delay stub 718 are used to adjust the delay between the horizontal electric field radiator 704 and the vertical backside patch 708, which is the second electric field radiator.

In each of the embodiments of the antenna shown above, the magnetic loop as a whole has a first inductive reactance, and this first inductive reactance must match the combined capacitive reactance of the other components of the antenna, such as the first capacitive reactance of the first electric field radiator, the second capacitive reactance of the physical arrangement between the first electric field radiator and the magnetic loop, the third capacitive reactance of the second electric field radiator, and the fourth capacitive reactance of the physical arrangement between the second electric field radiator and the magnetic loop. Likewise, it should be understood that other elements may contribute inductive and capacitive reactance that must be matched or balanced throughout the antenna to achieve proper performance.

One embodiment is directed to a single-sided circularly polarized self-contained composite loop antenna, comprising: a magnetic loop located on a plane and configured to generate a magnetic field, wherein the magnetic loop has a first inductive reactance that adds to a total inductive reactance of the composite loop antenna; a first electric field radiator located on a plane and configured to emit a first electric field orthogonal to the magnetic field, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance; a second electric field radiator located on the plane and configured to emit a second electric field out of phase with the first electric field, the second electric field orthogonal to the magnetic field and orthogonal to the first electric field, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, wherein the second electric field radiator has a third capacitive reactance that adds to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance that adds to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

The present embodiment may further include a counterpoise formed on the magnetic ring and having a counterpoise width greater than a width of the magnetic ring, the counterpoise positioned at a location selected from the group consisting of: opposite the first electric field radiator, opposite the second electric field radiator, and opposite the first and second electric field radiators.

The present embodiment may also include a transition piece formed on the magnetic loop and positioned along the magnetic loop ahead of the counterpoise, the transition piece having a transition piece width greater than a width of the magnetic loop and substantially creating a phase delay of approximately 180 degrees relative to the counterpoise.

This embodiment may also include a balun that cancels the common mode current and adjusts the antenna to a desired input impedance.

In this embodiment, the first electric field radiator may be directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection. The first electric field radiator may also be coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

In this embodiment, the second electric field radiator may be directly coupled to the magnetic loop at a point where the current flowing through the magnetic loop is substantially at a minimum of reflection. The second electric field radiator may also be coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

In this embodiment, the first electric field radiator may be directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

In this embodiment, the first electric field radiator may be coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to match an electrical length of the second electric field radiator.

In this embodiment, the antenna may further include one or more delay loops formed on one or more sides of the magnetic loop, the one or more delay loops introducing an electrical delay between the first and second electric field radiators, wherein the electrical delay ensures that the first and second electric fields are transmitted out of phase. The delay rings of the one or more delay rings may be substantially rectangular in shape or substantially smoothly curved in shape.

In this embodiment, the antenna may further include one or more delay stubs formed at one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

In this embodiment, the magnetic ring may be substantially rectangular in shape with one or more corners cut at an angle. In the present embodiment, the first electric field radiator may be vertically oriented and the second electric field radiator may be horizontally oriented, or the first electric field radiator may be horizontally oriented and the second electric field radiator may be vertically oriented.

Yet another embodiment is directed to a multi-layer circularly polarized self-contained composite loop antenna, comprising: a magnetic loop located on a first plane and configured to generate a magnetic field, wherein the magnetic loop has a first inductive reactance that adds to a total inductive reactance of the composite loop antenna; a first electric field radiator located on a first plane and configured to emit a first electric field orthogonal to the magnetic field, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance; a second electric field radiator located on the first plane and configured to emit a second electric field out of phase with the first electric field, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, the second electric field orthogonal to the first electric field and the magnetic field, wherein the second electric field radiator has a third capacitive reactance adding to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance adding to the total capacitive reactance; and a patch located on a second plane below the first plane, the patch having a third orientation parallel to the first orientation and orthogonal to the second orientation, the patch configured to emit a third electric field orthogonal to the magnetic field and the second electric field, the third electric field being emitted in phase with the first electric field and out of phase with the second electric field, wherein the patch has a fifth capacitive reactance added to the total capacitive reactance, wherein a third physical arrangement between the patch and the magnetic loop produces a sixth capacitive reactance added to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

In this embodiment, the antenna may further include a substantially rectangular portion cut out of the patch to reduce capacitive coupling between the patch and the second electric field radiator or the first electric field radiator. The antenna may further include a counterpoise formed on the magnetic loop and having a counterpoise width greater than a loop width of the magnetic loop, the counterpoise positioned at a location selected from the group consisting of: opposite the first electric field radiator, opposite the second electric field radiator, and opposite the first and second electric field radiators. The antenna may also include a transition formed on the magnetic loop and positioned along the magnetic loop in front of the counterpoise, the transition having a transition width greater than the loop width and producing a phase delay of substantially 180 degrees with respect to the counterpoise.

In this embodiment, the antenna may include a balun that cancels the common mode current and adjusts the antenna to a desired input impedance.

In this embodiment, the first electric field radiator may be directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and wherein the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

In this embodiment, the first electric field radiator may be coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to substantially match an electrical length of the second electric field radiator.

In this embodiment, the antenna may include one or more delay stubs formed on one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

In this embodiment, the magnetic ring may be substantially rectangular in shape with one or more corners cut at an angle. The first electric field radiator may be vertically oriented and the second electric field radiator may be horizontally oriented, or the first electric field radiator may be horizontally oriented and the second electric field radiator may be vertically oriented.

While the invention has been shown and described herein with several alternatives, it should be understood that the techniques described herein may have a number of additional uses and applications. Therefore, the present invention should not be limited to the specific description, embodiments and drawings contained in this specification which illustrate only the preferred embodiments, alternatives and application of the principles of the present invention.

The claims (modification according to treaty clause 19)

1. A single-sided non-linearly polarized self-contained composite loop antenna, comprising:

a magnetic loop located on a plane and configured to generate a magnetic field, wherein the magnetic loop has a first inductive reactance that adds to a total inductive reactance of the composite loop antenna;

a first electric field radiator located on the plane and configured to emit a first electric field orthogonal to the magnetic field at a first frequency, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance; and

a second electric field radiator located on the plane and configured to emit a second electric field at the first frequency, the second electric field orthogonal to the magnetic field and orthogonal to the first electric field, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, wherein the second electric field radiator has a third capacitive reactance that adds to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance that adds to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

2. The antenna as recited in claim 1, further comprising a counterpoise formed on the magnetic loop and having a counterpoise width that is greater than a width of the magnetic loop, the counterpoise being positioned at a location selected from the group consisting of: opposite the first electric field radiator, opposite the second electric field radiator, and opposite the first and second electric field radiators.

3. The antenna as recited in claim 2, further comprising a transition formed on the magnetic loop and positioned along the magnetic loop in front of the counterpoise, the transition having a transition width greater than a width of the magnetic loop and producing substantially an approximately 180 degree phase delay to the counterpoise.

4. The antenna of any preceding claim, further comprising a balun that cancels common mode currents and adjusts the antenna to a desired input impedance.

5. The antenna as recited in claim 1, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

6. The antenna as recited in claim 1, wherein the first electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

7. The antenna as recited in claim 1, wherein the second electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

8. The antenna as recited in claim 1, wherein the second electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

9. The antenna as recited in claim 1, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and wherein the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

10. The antenna as recited in claim 1, wherein the first electric field radiator is coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to match an electrical length of the second electric field radiator.

11. The antenna as recited in claim 1, further comprising one or more delay loops formed on one or more sides of the magnetic loop, the one or more delay loops introducing an electrical delay between the first and second electric field radiators, wherein the electrical delay ensures that the first and second electric fields are transmitted out of phase.

12. The antenna of claim 11, wherein a delay loop of the one or more delay loops is substantially rectangular in shape or is substantially smoothly curved in shape.

13. The antenna as recited in claim 1, further comprising one or more delay stubs formed on one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

14. The antenna as recited in claim 1, wherein the magnetic loop is substantially rectangular in shape with one or more corners cut at an angle.

15. The antenna of claim 1, wherein the first electric field radiator is oriented vertically and the second electric field radiator is oriented horizontally.

16. A multilayer non-linearly polarized self-contained composite loop antenna comprising:

a magnetic loop located on a first plane and configured to generate a magnetic field, wherein the magnetic loop has a first inductive reactance that adds to a total inductive reactance of the composite loop antenna;

a first electric field radiator located on the first plane and configured to emit a first electric field orthogonal to the magnetic field at a first frequency, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance; and

a second electric field radiator located on the first plane and configured to emit a second electric field at a second frequency different from the first frequency, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, the second electric field orthogonal to the first electric field and the magnetic field, the first frequency different from the second frequency, wherein the second electric field radiator has a third capacitive reactance that adds to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance that adds to the total capacitive reactance.

17. The antenna as recited in claim 16, further comprising a counterpoise formed on the magnetic loop and having a counterpoise width that is greater than a loop width of the magnetic loop, the counterpoise being positioned at a location selected from a group consisting of: opposite the first electric field radiator, opposite the second electric field radiator, and opposite the first and second electric field radiators.

18. The antenna as recited in claim 17, further comprising a transition formed on the magnetic loop and positioned along the magnetic loop in front of the counterpoise, the transition having a transition width greater than the loop width and substantially creating a phase delay of approximately 180 degrees for the counterpoise.

19. The antenna of claim 16, further comprising a balun that cancels common mode currents and adjusts the antenna to a desired input impedance.

20. The antenna as recited in claim 16, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

21. The antenna as recited in claim 16, wherein the first electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

22. The antenna as recited in claim 16, wherein the second electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

23. The antenna as recited in claim 16, wherein the second electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

24. The antenna as recited in claim 16, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and wherein the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

25. The antenna as recited in claim 16, wherein the first electric field radiator is coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to substantially match an electrical length of the second electric field radiator.

26. The antenna as recited in claim 16, further comprising one or more delay loops formed on one or more sides of the magnetic loop, the one or more delay loops introducing an electrical delay between the first and second electric field radiators, wherein the electrical delay ensures that the first and second electric fields are transmitted out of phase.

27. The antenna of claim 26, wherein a delay loop of the one or more delay loops is substantially rectangular in shape or is substantially smoothly curved in shape.

28. The antenna as recited in claim 16, further comprising one or more delay stubs formed on one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

29. The antenna as recited in claim 16, wherein the magnetic loop is substantially rectangular in shape with one or more corners cut at an angle.

30. The antenna of claim 16, wherein the first electric field radiator is oriented vertically and the second electric field radiator is oriented horizontally.

31. The antenna as recited in claim 16, further comprising a patch located on a second plane below the first plane, the patch having a third orientation parallel to the first orientation and orthogonal to the second orientation, the patch configured to emit a third electric field orthogonal to the magnetic field and the second electric field, the third electric field being emitted in phase with the first electric field and out of phase with the second electric field, wherein the patch has a fifth capacitive reactance that adds to the total capacitive reactance, wherein a third physical arrangement between the patch and the magnetic loop produces a sixth capacitive reactance that adds to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

32. The antenna of claim 31, further comprising a generally rectangular portion cut from the patch to reduce capacitive coupling between the patch and the second electric field radiator.

Claims

1. A single-sided circularly polarized self-contained composite loop antenna, comprising:

a first electric field radiator located on the plane and configured to emit a first electric field orthogonal to the magnetic field, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance; and

a second electric field radiator located on the plane and configured to emit a second electric field out of phase with the first electric field, the second electric field orthogonal to the magnetic field and orthogonal to the first electric field, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, wherein the second electric field radiator has a third capacitive reactance adding to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance adding to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

5. The antenna as recited in any one of the preceding claims, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

6. The antenna as recited in any one of claims 1 to 4, wherein the first electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

7. The antenna as recited in any one of the preceding claims, wherein the second electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

8. The antenna as recited in any one of claims 1 to 6, wherein the second electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

9. The antenna as recited in any one of claims 1 to 4, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and wherein the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

10. The antenna as recited in any one of claims 1 to 8, wherein the first electric field radiator is coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to match an electrical length of the second electric field radiator.

11. The antenna as recited in any one of the preceding claims, further comprising one or more delay loops formed on one or more sides of the magnetic loop, the one or more delay loops introducing an electrical delay between the first and second electric field radiators, wherein the electrical delay ensures that the first and second electric fields are transmitted out of phase.

13. The antenna as recited in any one of the preceding claims, further comprising one or more delay stubs formed on one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

14. An antenna as claimed in any preceding claim, wherein the magnetic loop is substantially rectangular in shape with one or more corners cut at an angle.

15. The antenna according to any of the preceding claims, wherein the first electric field radiator is oriented vertically and the second electric field radiator is oriented horizontally.

16. A multi-layer circularly polarized self-contained composite loop antenna comprising:

a first electric field radiator located on the first plane and configured to emit a first electric field orthogonal to the magnetic field, the first electric field radiator coupled to the magnetic loop and having a first orientation, wherein the first electric field radiator has a first capacitive reactance that adds to a total capacitive reactance of the composite loop antenna, and wherein a first physical arrangement between the first electric field radiator and the magnetic loop produces a second capacitive reactance that adds to the total capacitive reactance;

a second electric field radiator located on the first plane and configured to emit a second electric field out of phase with the first electric field, the second electric field radiator coupled to the magnetic loop and having a second orientation orthogonal to the first orientation, the second electric field orthogonal to the first electric field and the magnetic field, wherein the second electric field radiator has a third capacitive reactance adding to the total capacitive reactance, wherein a second physical arrangement between the second electric field radiator and the magnetic loop produces a fourth capacitive reactance adding to the total capacitive reactance; and

a patch located on a second plane below the first plane, the patch having a third orientation parallel to the first orientation and orthogonal to the second orientation, the patch configured to emit a third electric field orthogonal to the magnetic field and the second electric field, the third electric field emitted in-phase with the first electric field and out-of-phase with the second electric field, wherein the patch has a fifth capacitive reactance adding to the total capacitive reactance, wherein a third physical arrangement between the patch and the magnetic loop produces a sixth capacitive reactance adding to the total capacitive reactance, and wherein the total inductive reactance substantially matches the total capacitive reactance.

17. The antenna of claim 16, further comprising a substantially rectangular portion cut from the patch to reduce capacitive coupling between the patch and the second electric field radiator.

18. The antenna as recited in claim 16 or 17, further comprising a counterpoise formed on the magnetic loop and having a counterpoise width that is greater than a loop width of the magnetic loop, the counterpoise being positioned at a location selected from a group consisting of: opposite the first electric field radiator, opposite the second electric field radiator, and opposite the first and second electric field radiators.

19. The antenna as recited in claim 18, further comprising a transition formed on the magnetic loop and positioned along the magnetic loop in front of the counterpoise, the transition having a transition width greater than the loop width and substantially creating a phase delay of approximately 180 degrees for the counterpoise.

20. The antenna of any one of claims 16 to 19, further comprising a balun that cancels common mode currents and adjusts the antenna to a desired input impedance.

21. The antenna as recited in any one of claims 16 to 20, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

22. The antenna as recited in any one of claims 16 to 20, wherein the first electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

23. The antenna as recited in any one of claims 16 to 22, wherein the second electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

24. The antenna as recited in any one of claims 16 to 22, wherein the second electric field radiator is coupled to the magnetic loop via an electrical trace at a point where current flowing through the magnetic loop is substantially at a reflective minimum.

25. The antenna as recited in any one of claims 16 to 20, wherein the first electric field radiator is directly coupled to the magnetic loop at a point where current flowing through the magnetic loop is substantially at a minimum of reflection, and wherein the second electric field radiator is directly coupled to the first electric field radiator at: at this point, the electrical delay between the feed point of the first electric field radiator and the feed point of the second electric field radiator ensures that the first electric field radiator is out of phase with the second electric field radiator.

26. The antenna as recited in any one of claims 16 to 25, wherein the first electric field radiator is coupled to the magnetic loop on a first side, and wherein a physical length of the first electric field radiator is less than a physical length of the second electric field radiator, the antenna further comprising a substantially rectangular stub directly coupled to a second side of the magnetic loop opposite the first side, the stub adjusting an electrical length of the first electric field radiator to substantially match an electrical length of the second electric field radiator.

27. The antenna as recited in any one of claims 16 to 26, further comprising one or more delay loops formed on one or more sides of the magnetic loop, the one or more delay loops introducing an electrical delay between the first and second electric field radiators, wherein the electrical delay ensures that the first and second electric fields are transmitted out of phase.

28. The antenna of claim 27, wherein a delay loop of the one or more delay loops is substantially rectangular in shape or is substantially smoothly curved in shape.

29. The antenna as recited in any one of claims 16 to 28, further comprising one or more delay stubs formed on one or more sides of the magnetic loop, the one or more delay stubs being generally rectangular, wherein the one or more delay stubs introduce an electrical delay between the first and second electric field radiators to ensure that the first and second electric fields are transmitted out of phase.

30. The antenna as recited in any one of claims 16 to 29, wherein the magnetic loop is substantially rectangular in shape with one or more corners cut at an angle.

31. The antenna according to any one of claims 16 to 30, wherein the first electric field radiator is oriented vertically and the second electric field radiator is oriented horizontally.