MXPA99001096A - Dual-band coupled segment helical antenna - Google Patents

Abstract

A dual-band coupled-segment helical antenna is provided operating in two frequency bands. The dual-band coupled-segment helical antenna (1200) includes a radiator portion (1202) having two sets of one or more helically wound radiators (1204, 1212) extending from one end (1234) of the radiator portion (1202) to the other end (1232) of the radiator portion (1202). Radiators of the firs set of radiators (1204) are comprised of two segments:a first radiator segment (1208) extends in a helical fashion from one end of the radiator portion (1202) toward the other end of the radiator portion (1202);and a second radiator segment (1210) is U-shaped and extends in a helical fashion from the first end of the radiator portion (1202) toward the second end of the radiator portion (1202). Radiators of the second set of radiators (1212) are comprised of a radiator (1212) disposed within said U-shaped segment (1210). The first set of radiators (1204) resonates at a first frequency and the second set of radiators (1212) resonates at a second frequency thereby providing dual-band operation, with minimal coupling between the frequency bands.

Description

HELICOIDAL ANTENNA WITH SEGMENTS COUPLED FOR DUAL BAND BACKGROUND OF THE INVENTION I. Field of the Invention The invention relates generally to helical antennas and more specifically to a helical antenna for dual band having radiator segments.

II. Field of the Invention Contemporary personal communication devices enjoy widespread use in numerous mobile and portable applications. With traditional mobile applications, the desire to minimize the size of the communication device, such as a mobile phone, led to a moderate level of size reduction. However, as hand-held, portable applications grew in popularity, the demand for smaller and smaller devices increased dramatically. Recent improvements in processor technology, battery technology and communications technology have allowed the size and weight of the portable device to be drastically reduced in recent years. An area in which reductions of P1121 / 99MX size is in the antenna of the devices. The size and weight of the antenna play an important role in decreasing the size of the communication device. The total size of the antenna can impact the size of the body of the device. Antennas of smaller diameter and shorter length may allow smaller sizes of the complete device as well as smaller body sizes. The size of the communication device is not the only factor that needs to be considered in the design of antennas for portable applications. Another factor to be considered in antenna design is the attenuation and / or blocking effects that result from the proximity of the user's head to the antenna during normal operations. Still another factor are the radiation patterns and the desired operating frequencies. An antenna that finds wide use in satellite communication systems is the helical antenna. One reason for the popularity of the helical antenna in satellite communication systems is its ability to produce and receive circularly polarized radiation used in such systems. Additionally, because the helical antenna is capable of producing a radiation pattern that is almost hemispherical, the helical antenna is particularly well suited for P1121 / 99MX applications in satellite communication systems and in navigational satellite systems. Conventional helical antennas are made by rotating the radiators of the antenna towards a helical structure. A common helical antenna is the quadrilateral helical antenna that uses four radiators equally spaced around a core and excited in quadrature phase (ie, the radiators are excited by signals that differ in phase by 1/4 of a period or 90 °) . The length of the radiators is typically an integral multiple of the quarter wavelength of the operating frequency of the communication device. The radiation patterns are typically adjusted by varying the inclination of the radiator, the length of the radiator (in whole multiples of a quarter wavelength), and the diameter of the core. Conventional helical antennas can be made by the use of wire or tape technology. With tape technology, the radiators of the antenna are recorded or deposited on a thin, flexible substrate. The radiators are placed in such a way that they are parallel to each other, but at an obtuse angle towards the sides of the substrate. The substrate is then formed, or rolled up, into a cylindrical, conical or other suitable shape which causes the ribbon radiators to form a helix.

P1121 / 99MX However, this conventional helical antenna also has the characteristic that the radiators are an integer multiple of a quarter wavelength of the desired resonant frequency, resulting in a total antenna length that is greater than desired for some portable or mobile applications. Additionally, in applications where the transmission and reception of communications occurs at different frequencies, antennas for double band are desirable. However, dual-band antennas are often only available in fewer configurations than desirable. For example, one way in which an antenna can be made for dual band is to stack two tetrafilar propeller antennas of a single end to end band, in such a way that they form a single cylinder. However, a disadvantage of this solution is that the antenna is larger than would otherwise be desired for portable or hand held applications. Another technique for providing dual band execution has been to use two separate antennas of a single band. However, for units held by the hand, the two antennas would have to be placed in close proximity to each other. The two single-band antennas, placed in close proximity in a portable unit or held by the hand, would cause the coupling between the two antennas, P1121 / 99MX leading to degraded execution as well as undesirable interference.

SUMMARY OF THE INVENTION The present invention is a helical antenna for dual band, novel and improved having two sets of one or more helically wound radiators. The radiators are wound in such a way that the antenna is in a cylindrical, conical or other suitable shape to optimize or otherwise obtain the desired radiation patterns. According to the invention, a set of radiators is provided for operation at a first frequency and the second set is provided for operation at a second frequency that is different from the first frequency. In the first set of one or more radiators, each radiator consists of two radiator segments. A radiator segment extends in a helical shape from one end of a radiator portion of the antenna to the other end of the radiator portion. A second radiator segment extends in a helical form from the first end of the radiator portion to the second end of the radiator portion. This second radiator segment is preferably U-shaped. The term "U-shape" is used in P1121 / 99MX this document to refer to a U shape, v-shape, fork shape, horseshoe shape or other similar or similar shape. As a result of this structure, the electromagnetic energy from the first segment of a radiator in the first assembly engages in the second segment of that radiator. The effective electrical length of these combined segments causes the radiator in the first set of one or more radiators to resonate at a given frequency. Because the segments physically separate but electromagnetically couple together, the length at which the radiator resonates for a specific frequency can be made shorter than that of a conventional helical antenna radiator. In the second set of one or more radiators, each radiator is placed in such a way that it is surrounded by the U-shaped segment. This has the effect of electromagnetically insulating or coating the radiator in the first assembly from the first radiator segment in the first set. An advantage of the invention is that for a specific operating frequency, the first set of radiators can be made to resonate at a shorter physical length and / or at a smaller volume than conventional helical antenna radiators with the same length of P1121 / 99MX effective resonance. In this way, the size of the antenna required for operation on the first frequency is smaller than that of conventional antennas. Another advantage of the helical antenna of coupled segments for double band is that the second set of one or more radiators for operation at the second frequency is provided without increasing the total length of the antenna. This is because the second set of one or more of the radiators is intercalated with the one or more radiators of segments coupled in the first set. Another advantage of the coupled multi-segment helical antenna is that it can easily be tuned to a specific frequency by adjusting or adjusting the length of the radiator segments in the first set of radiators or by adjusting the length of one or more of the radiators in the second set. Because one or more of the radiators in the first set are not in a single contiguous length, but rather are made from a set of two or more overlapping segments, the length of the segments can be easily mortified after the antenna has been developed to properly tune to the frequency of the antenna by adjusting the radiators. Additionally, the total radiation pattern of the antenna is essentially not modified by tuning because the length P1121 / 99MX total physics of the radiator portion of the antenna is not modified by the adjustment. Still another advantage of the invention is that its directional characteristics can be adjusted to maximize the resistance of the signal in a preferred direction along the axis of the antenna. In this way, for certain applications, such as for example satellite communications, the directional characteristics of the antenna can be optimized to maximize the resistance of the signal in the upward direction, away from the ground. The additional features and advantages of the present invention, as well as the structure and operation of the various embodiments of the present invention, are described below in detail in the following with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The features, objects and advantages of the present invention will become more apparent from the following detailed description established when taken in conjunction with the drawings in which the same reference numbers are consistently used and where: Figure 1A is a diagram illustrating a P1121 / 99MX conventional wire tetrafilar helical antenna. Figure IB is a diagram illustrating a conventional tape tetrafilar helical antenna. Figure 2A is a diagram illustrating a planar representation of an open circuit tetrafilar helical antenna. Figure 2B is a diagram illustrating a planar representation of a short circuit four-wire helical antenna. Figure 3 is a diagram illustrating the distribution of current in a radiator of a short-circuited four-wire helical antenna. Figure 4 is a diagram illustrating a far surface of an etched substrate of a helical ribbon antenna. Figure 5 is a diagram illustrating a close surface of an etched substrate of a helical ribbon antenna. Figure 6 is a diagram illustrating a perspective view of an etched substrate of a helical ribbon antenna. Figure 7A is a diagram illustrating a radiator of multiple segments coupled in open circuit, having five segments coupled. Figure 7B is a diagram illustrating a pair of P1121 / 99MX multi-segment radiators coupled in short circuit. Figure 8A is a diagram illustrating a planar representation of a quadrilateral helical antenna of multiple segments coupled in short circuit. Figure 8B is a diagram illustrating a quadrilateral helical antenna of multiple coupled segments, shaped into a cylindrical shape. Figure 9A is a diagram illustrating the overlap d and spacing s of the radiator segments according to one embodiment of the invention. Fig. 9B is a diagram illustrating exemplary current distributions in radiator segments of the coupled multi-segment helical antenna. Figure 10A is a diagram illustrating two point sources that radiate signals that differ in phase by 90 °. Figure 10B is a diagram illustrating field patterns for the dot origins illustrated in Figure 10A. Figure 11 is a diagram illustrating a mode in which each segment is equidistant to the segments on each side. Figure 12A is a diagram illustrating a P1121 / 99MX flat representation of a helical antenna with coupled segments where one segment of each radiator is U-shaped. Figure 12B is a diagram illustrating a planar representation of a helical antenna of coupled segments for double band according to an embodiment of the invention. Fig. 13 is a diagram illustrating an exemplary current distribution in a portion of a helical antenna of coupled segments for double band. Figure 14A is a diagram illustrating a far surface of a helical antenna of coupled segments for double band according to an embodiment of the invention. Figure 14B is a diagram illustrating a close surface of a helical antenna of coupled segments for dual band according to one embodiment of the invention. Figure 15 is a diagram illustrating the superimposed near and far surfaces. Fig. 16 is a diagram illustrating an exemplary schematic distribution (both near and far surfaces) of a helical antenna of coupled dual-band segments according to an embodiment of P1121 / 99MX the invention. Figure 17 is a diagram illustrating an exemplary schematic distribution (both near and far surfaces) of a helical antenna of coupled dual-band segments according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES I. General View and Discussion of the Invention The present invention is directed towards a helical antenna having multiple segment radiators coupled to shorten the length of the radiators for a specific resonant frequency, thereby reducing the total length of the antenna. The manner in which all this is carried out is described below in detail according to various modalities.

II. Exemplary Environment In the broadest sense, the invention can be implemented in any system for which helical antenna technology can be used. An example of such an environment is a communications system in which users who have landline, mobile and / or portable telephones communicate with other parties through a satellite communication link. In this environment For example, P1121 / 99MX requires that the telephone has an antenna tuned to the frequency of the satellite communication link. The present invention is described in terms of this exemplary environment. The description in these terms is provided solely for convenience. The invention is not intended to be limited to the application in this exemplary environment. In fact, after reading the following description, it will become apparent to a person skilled in the relevant art how to implement the invention in alternative environments.

III. Conventional Helical Antennas Before describing the invention in detail, it is useful to describe the radiator portions of some conventional helical antennas. Specifically, this section of the document describes radiator portions of some conventional tetrafilar helical antennas. Figures IA and IB are diagrams illustrating a portion of radiator 100 of a conventional wire-shaped tetrafilar helical antenna and ribbon-shaped, respectively. The radiator portion 100 illustrated in Figures IA and IB is that of a tetrafilar helical antenna, meaning that it has four radiators 104 operating in quadrature of phase. As illustrated in P1121 / 99 X Figures IA and IB, the radiators 104 are wound to provide circular polarization. Possible signal feed points for the radiators of figure IB are shown. Figures 2A and 2B are diagrams illustrating planar representations of a radiator portion of conventional tetrafilar helical antennas. In other words, Figures 2A and 2B illustrate the radiators as they would appear if the antenna cylinder were "unrolled" on a flat surface. Figure 2A is a diagram illustrating a tetrafilar helical antenna that is open circuit at the far end. For such a configuration, the resonant length de of the radiators 208 is an odd integer multiple of a quarter wavelength of the desired resonant frequency. Figure 2B is a diagram illustrating a tetrafilar helical antenna that is short-circuited at the far end. In this case, the resonant length i of the radiators 208 is an even integral multiple of a quarter wavelength of the desired resonant frequency. Note that in both cases, the established resonant length i is approximate, because a small adjustment is usually needed to compensate for short non-ideal and open terminations. Figure 3 is a diagram illustrating a P1121 / 99MX flat representation of a radiator portion of a tetrafilar helical antenna 300, which includes radiators 208 having a length l =? / 2, where? is the wavelength of the desired resonant frequency of the antenna. Curve 304 represents a current of a signal in a radiator 208 that resonates at a frequency of = v / ?, where v is the speed of the signal in the medium. Exemplary implementations of a tetrafilar helical antenna implemented by the use of printed circuit board techniques (a ribbon antenna) are described in more detail with reference to Figures 4-6. The quadrilateral helical ribbon antenna is comprised of radiators of tape 104 recorded on a dielectric substrate 406. The substrate is a thin flexible material that is wound into a cylindrical shape in such a way that the radiators 104 are wound helically around a central axis of the cylinder. Figures 4-6 illustrate the components used to fabricate a tetrafilar helical antenna 100. Figures 4 and 5 present a view of a far surface 400 and a near surface 500 of the substrate 406, respectively. The antenna 100 includes a radiator portion 404 and a feed portion 408. In the embodiments described and illustrated herein, the antennas are described as being processed.

P1121 / 99MX by forming the substrate in a cylindrical shape, with the near surface on the outer surface of the formed cylinder. In the alternative modalities, the substrate is formed in the cylindrical form, the far surface being found on the external surface of the cylinder. In one embodiment, the dielectric substrate 100 is a thin, flexible layer of polytetrafluoroethanol (PTFE), a PTFE / glass compound, or other dielectric material. In one embodiment, the substrate 406 is of the order of 0.005 inches, or 0.13 mm thick, although other thicknesses may be chosen. Traces of the signal and traces of the soil are provided by the use of copper. In alternative modes, other conductive materials can be chosen instead of copper, depending on cost, environmental considerations and other factors. In the embodiment illustrated in Figure 5, the supply network 508 is recorded on the feed portion 408 to provide the signals in quadrature phase (ie, the signals of 0o, 90 °, 180 ° and 270 °) which are provide the radiators 10. The feed portion 408 of the far surface 400 provides a terrestrial plane 412 for the feed circuit 508. The traces of the signal for the feed circuit 508 are recorded on the near surface 500 of the portion Feed P1121 / 99MX 408. For discussion purposes, the radiator portion 404 has a first end 432 adjacent to the feed portion 408 and a second end 434 (at the opposite end of the radiator portion 404). Depending on the embodiment of the antenna implemented, the radiators 104 can be etched on the far surface 400 of the radiator portion 404. The length at which the radiators 104 extend from the first end 432 to the second end 434 is approximately a multiple. an entire quarter wavelength of the desired resonant frequency. In such a mode where the radiators 104 are an integer multiple of? / 2, the radiators 104 are electrically connected to each other (ie, shortened or short-circuited) at the second end 434. This connection can be made by a conductor through the second end 434 which forms a ring 604 around the circumference of the antenna when the substrate is formed into a cylinder. Figure 6 is a diagram illustrating a perspective view of an etched substrate of a tape helical antenna having a shortening ring 604 at the second end 434. A conventional tetrafilar helical antenna is described in U.S. Patent No. 5,198,831, from P1121 / 99MX Burrell et al., (Referred to as the 831 patent), which is incorporated herein by reference. The antenna described in the '831 patent is a printed circuit board antenna having the antenna radiators etched or otherwise deposited on a dielectric substrate. The substrate is formed into a cylinder which results in the helical configuration of the radiators. Another conventional tetrafilar helical antenna is disclosed in U.S. Patent No. 5,255,005 to Terret et al., (Referred to as the "x005 patent") which is incorporated herein by reference. The antenna described in the patent x 005 is a tetrafilar helical antenna formed by two bifilar helices placed orthogonally and excited in quadrature phase. The exposed antenna also has a second tetrafilar helix that is coaxial and electromagnetically coupled with the first helix to improve the ribbon pitch of the antenna. Still another conventional tetrafilar helical antenna is set forth in U.S. Patent No. 5,349,365, Ow and co., (Referred to as the 365 patent) which is incorporated herein by reference. The antenna described in the? 365 patent is a tetrafilar helical antenna designed in wire form as described above with reference to FIG.P1121 / 99MX IV. Multi-Segment Helical Antenna Coupled One variation of the conventional helical antenna is a helical antenna with multiple coupled segments, which is now described in terms of various modalities. In order to reduce the length of the radiator portion 100 of the antenna, the invention utilizes coupled multiple-segment radiators that allow resonance at a specific frequency in shorter lengths than would otherwise be necessary for a conventional helical antenna with an equivalent resonant length. Figures 7A and 7B are diagrams illustrating planar representations of exemplary embodiments of coupled segment helical antennas. Figure 7A illustrates a radiator of multiple coupled segments 706 terminated in an open circuit according to a monofilar modality. An antenna terminated in an open circuit such as this can be used in a monofilar, bifilar, tetrafilar, or other x-filar implementation. The embodiment illustrated in Figure 7A is comprised of a single radiator 706. The radiator 706 is comprised of a set of radiator segments. This set is comprised of two end segments 708, 710 and p intermediate segments 712, where p - 0,1,2,3 ... (the case where p = 3 is illustrated). The intermediate segments P1121 / 99MX are optional (that is, p can equal zero). The end segments 708, 710 physically separate, but they are electromagnetically coupled to each other. The intermediate segments 712 are placed between the end segments 708, 710 and provide an electromagnetic coupling between the end segments 708, 710. In the open circuit mode, the length of the segment 708 is an odd integer multiple of a quarter. of wavelength of the desired resonant frequency. The length _. of segment 710 is an integer multiple of one half the wavelength of the desired resonant frequency. The length i of each of the p intermediate segments 712 is an integer multiple of one half of the wavelength of the desired resonant frequency. In the illustrated embodiment, there are three intermediate segments 712 (ie, p = 3). Figure 7B illustrates the radiators 706 of the helical antenna when terminating in a short circuit 722. This short circuit implementation is not suitable for a monofilar antenna, but can be used for bifilar, tetrafilar or other x-filar antennas. As with the open circuit mode, the radiators 706 are comprised of a set of radiator segments. This set is comprised of two end segments 708, 710 and p intermediate segments 712, where p = 0,1,2,3 ... (is P1121 / 99MX illustrates the case where p = 3). The intermediate segments are optional (that is, p can equal zero). The end segments 708, 710 physically separate, but they are electromagnetically coupled to each other. The intermediate segments 712 are placed between the end segments 708, 710 and provide an electromagnetic coupling between the end segments 708, 710. In the short circuit mode, the length x 8 of the segment 708 is an odd integer multiple of a quarter of wavelength of the desired resonant frequency. The length "sl" of segment 710 is an odd integer multiple of a quarter wavelength of the desired resonant frequency. The length l of each of the p intermediate segments 712 is an integer multiple of one half of the wavelength of the desired resonant frequency. In the illustrated embodiment, there are three intermediate segments 712 (ie, p = 3). Figures 8A and 8B are diagrams illustrating a quadrilateral helical antenna radiator portion of multiple coupled segments 800. Figures 8A and 8B illustrate an exemplary implementation of the antenna illustrated in Figure 7B, where p = zero (ie, no there are intermediate segments 712) and the lengths of the segments 708, 710 are one quarter wavelength. The radiator portion 800 illustrated in the figure P1121 / 99MX 8A is a planar representation of a tetrafilar helical antenna having four coupled radiators 804. Each coupled radiator 804 in the coupled antenna is actually comprised of two radiator segments 708, 710 positioned in close proximity to each other, such that the energy in the radiator segment 708 is coupled to the other radiator segment 710. More specifically, according to one embodiment, the radiator portion 800 can be described in terms as having two sections 820, 824. The section 820 is comprised of a plurality of radiator segments 708 extending from a first end 832 of the radiator portion 800 to the second end 834 of the radiator portion 800. The section 824 is comprised of a second plurality of radiator segments 710 extending from the second end 834 of the radiator portion 800 to the first end 832. To the central area of the radiator portion 800, a part of each segment 708 is located near an adjacent segment 710 such that energy from one segment is coupled to the adjacent segment in the proximity area. This relative proximity is referred to in this document as overlay. In one embodiment, each segment 708, 710 is of a length of approximately l = l -? / 4. The length P1121 / 99 X total of a single radiator comprising two segments 708, 710 is defined as "tot. The amount that a segment 708 overlays to another segment 710 is defined as d = ^ + i. - tot. For a resonant frequency = v /? The total length of a radiator is tot is less than half the wavelength of? / 2. In other words, as a result of a coupling, a radiator, comprising a pair of coupled segments 708, 710, resonates at a frequency / = v /? although the total length of that radiator is less than the length of? / 2. Accordingly, the radiator portion 800 of a quadrilateral helical antenna of multiple coupled segments, half wavelength, is shorter than the radiator portion of the conventional half wavelength tetrafilar helical antenna 800 for a specific frequency. . For a clearer illustration of the size reduction gained by using the coupled configuration, the radiator portions 800 illustrated in FIG. 8 are compared with those illustrated in FIG. 3. For a specific frequency / = v / ?, the length de of the radiator portion 300 of the conventional antenna is / / 2, while the length τ tot of the radiator portion 800 of the coupled radiator segment antenna is < ?/2. As stated in the above, in one embodiment, segments 708, 710 are of length t = l.

P1121 / 99MX =? / 4. The length of each segment can vary in such a way that lx is not necessarily equal to 22, and in such a way that they are not equal to / / 4. The actual resonant frequency of each radiator is a function of the length of the radiator segments 708, 710, the separation distance s between the radiator segments 708, 710 and the amount to which the segments 708, 710 overlap each other . Note that changing the length of a segment 708 with respect to the other segment 710 can be used to adjust the bandwidth of the antenna. For example, the elongation of ¿1 in such a way that it is slightly greater than? / 4 and the shortening of ¿2 in such a way that it is slightly shorter than? / 4, can increase the bandwidth of the antenna. Figure 8B illustrates the actual helical configuration of a quadrilateral helical antenna of multiple segments coupled according to one embodiment of the invention. This illustrates how each radiator is comprised of two segments 708, 710 in one embodiment. The segment 708 extends helically from the first end 832 of the radiator portion to the second end 834 of the radiator portion The segment 710 extends helically from the second end 834 of the radiator portion toward the radiator portion. first end 832 of the radiator portion Figure 8B further illustrates that a portion of segments 708, P1L21 / 99MX 710 are superimposed in such a way that they are electromagnetically coupled to each other. Figure 9A is a diagram illustrating the spacing s and the overlap d between the radiator segments 708, 710. The spacing s is chosen such that a sufficient amount of energy is coupled between the radiator segments 708, 710 to enable them to function as a single radiator of an effective electric length of approximately? / 2 and whole multiples thereof. Separation of the radiator segments 708, 710 closest to its optimum spacing results in a greater coupling between the segments 708, 710. As a result, for a specific frequency f the length of the segments 708, 710 must be increased to allow resonance at the same frequency. This can be illustrated by the extreme case in which the segments 708, 710 are physically connected (ie, s = 0). In this extreme case, the total length of segments 708, 710 must equal? / 2 for the antenna to resonate. Note that in this extreme case the antenna is no longer really 'coupled' according to the use of the term in this specification, and the resulting configuration is actually that of a conventional helical antenna such as that illustrated in Figure 3. Similarly , by increasing the amount of P1121 / 99MX overlap d of segments 708, 710 coupling is increased. In this way, as the overlap d increases, the length of the segments 708, 710 also increases. To qualitatively understand the optimal overlap and spacing for segments 708, 710, reference is made to Figure 9B. Figure 9B represents a magnitude of the current in each segment 708, 710. The current resistance indicators 911, 928 illustrate that each segment ideally resonates a? / 4, with the maximum signal strength at the outer ends and the minimum at the inner ends. To optimize the antenna configurations for the coupled radiator segment antenna, the inventor used modeling software to determine the correct segment lengths i1, i2, the superposition d and the separation s, among other parameters. One package of such software is the Antenna Optimizer (AO) software package. AO is based on an electromagnetic moments modeling algorithm method. The AO Anntena Optimizer version 6.35, copyright 1994, was written by and is available from Brian Beezley, of San Diego, California. Note that there are certain advantages obtained by using a coupled configuration as described in the foregoing with reference to FIGS. 8A and P1121 / 99MX 8B. With both the conventional antenna and the coupled radiator segment antenna, the current is concentrated at the ends of the radiators. According to the theory of the installation factor, this can be used as an advantage with the radiator segment antenna coupled in certain applications. As an explanation, FIG. 10A is a diagram illustrating two point sources, A, B, where the origin A radiates a signal having a magnitude equal to that of the signal of origin B but which is delayed in phase at 90a (FIG. assumes the convention 'Where origins A and B are separated by a distance of? / 4, the signals are added in phase in the direction that runs from A to B and are added out of phase in the direction from B to A. As As a result, very little radiation is emitted in the direction from B to A. A representative, typical field pattern shown in Figure 10B illustrates this point.Thus, when the origins A and B are oriented in such a way that the direction from points A to B is ascending, away from the ground, and the direction from points B to A is toward the ground, the antenna is optimized for most applications, this is because it is rare for a user to want an antenna that directs the signal resistance to the ground. This configuration is especially useful for satellite communications P1121 / 99MX where you want the majority of the signal resistance to be directed upward, away from the ground. The point origin antenna modeled in Figure 10A is not easily obtained by the use of conventional half wavelength helical antennas. Consider the antenna radiator portion illustrated in Fig. 3. The concentration of current resistance at the ends of the radiators 208 is quite close to a point origin. When the radiators are turned in a helical configuration, one end of the radiator of 902 is placed in line with the other end of the O2 radiator. In this way, this approximates the two point origins in a line. However, these approximate point sources are separated approximately? / 2 as opposed to the desired? / 4 configuration, illustrated in Fig. 10A. However, it should be noted that the coupled radiator segment antenna according to the invention provides an implementation where the approximate point sources are separated by a distance closer to / / 4. Accordingly, the coupled radiator segment antenna allows users to take advantage of the directional characteristics of the antenna illustrated in Figure 10A. The radiator segments 708, 710, illustrated in P1121 / 99MX Figure 8 show that segment 708 is very close to its associated segment 710, yet each pair of segments 708, 710 are relatively far from the pair of adjacent segments. In an alternative embodiment, each segment 710 is placed at the same distance from the segments 708 on each side. This embodiment is illustrated in Figure 11. Referring now to Figure 11, each segment is substantially equidistant from each pair of adjacent segments. For example, segment 708B is equidistant to segments 710A, 710B. That is, s? = s2. Similarly, segment 710A is equidistant to segments 708A, 708B. This modality is contrary to intuition, in which it seems as if the unwanted coupling existed. In other words, a segment corresponding to a phase would be coupled not only to the appropriate segment of the same phase, but also to the adjacent segment of the displaced phase. For example, segment 708B, segment 90e, would be coupled to segment 710A (segment 02) and segment 710B (segment 90 e). Such coupling is not a problem because the radiation from the upper segments 710 can be considered in two separate ways. Resulting one mode of linkage to segments adjacent to the left and other mode of P1121 / 99MX coupling to the adjacent segments on the right. However, both modes are in phase to provide radiation in the same direction. Therefore, this double coupling is not harmful to the operation of the antenna of multiple coupled segments. An additional advantage of the segmented radiator helical antenna is that it is very easy to tune after it has already been manufactured. The antenna can be tuned simply by adjusting segments 708, 710. Note that if desired, this can be done without changing the total length of the antenna.

V. Antenna of Coupled Segments for Dual Band In some applications, it is desirable to have an antenna that operates at two frequencies. An example of such an application is a communication system that operates at a frequency to transmit and a second frequency to receive. A conventional technique for carrying out the execution of the dual band is to stack two quadrilateral helical antennas of a single end-to-end band to form a single large cylinder. For example, a system designer can stack an L-Band and an S-Band antenna to achieve operational characteristics in both the L-Band and the S-Band. However, such a stack increases the overall length of the P1121 / 99MX antenna. To reduce the total length of the antenna for double band, the inventors have developed an antenna of coupled segments for double band that does not require the stacking of two helical antennas. The antenna of coupled segments for double band, according to the invention, effectively "overlaps" the two antennas of a single band, one on the other. Figure 12A is a diagram illustrating a planar representation of an antenna of multiple coupled dual-band segments 1200 having a U-shaped segment. In this embodiment, the radiator 1204 comprises a straight segment 1208 and a segment 1210 in the form U in a radiator portion 1202. The straight segment 1208 extends from a second end 1234 of the radiator portion 1202 to a first end 1232, while the U-shaped segment 1210 extends from the first end 1232 of the radiator portion 1202 to the second end 1234. The U-shaped segment 1210 may consist of a variety of different shapes approaching coarsely in a "U" or other partially close-up manner, such as: a fork, a horseshoe or another similar way. In the illustrated embodiment, the U-shaped segment 1210 can be described by having three sections: P1121 / 99MX first section 1262 extending from the first end 1232 to the second end 1234, a second section 1264 which is adjacent to the first section 1262 and a third section 1266 connecting the first and second sections 1262, 1264. The segment straight 1208 is in proximity with the U-shaped segment 1210 such that the segments 1208, 1210 are physically separated, but electromagnetically coupled together. In the illustrated embodiment, the vertices of the U-shaped segment 1210 are relatively sharp. In alternative embodiments, the vertices may be rounded, tapered, or in some other alternative way. To carry out the double band operation, a second helical antenna of a single segment is incorporated into the structure of the helical antenna of multiple coupled segments for a single band 1200. The helical antenna of coupled segments for dual band 1220 resulting is illustrated in Figure 12B according to one embodiment. The embodiment illustrated in Figure 12B is also a tetrafilar modality, although the dual-band antenna can be implemented in monofilar, bifilar and other x-filar modalities. Figure 12B is a planar representation of a helical antenna of coupled segments for double band, according to one embodiment of the invention. The antenna P1121 / 99MX 1220 consists of two sets of radiators 1204, 1212 that extend through a portion of radiator 1202. Each of the radiators 1204 and 1212 resonate at a designed operating frequency, thus providing dual-band operation. Radiators 1204 consist of segments 1208, 1210 as described above with reference to Figure 12A. Radiators 1204 resonate at a first operating frequency v /? 1. A supply network 1272 provides the quadrature signals of phase (ie, the signals of 0o, 90 °, 180 ° and 270 °) of the first frequency f = v /? 1 towards the radiators 1204. The radiators 1212 are arranged within the U-shaped segments 1210. Radiators 1212 resonate at a second operating frequency v / 2. A power supply network 1274 provides the phase quadrature signals (ie, the 0, 90, 180 and 270 degrees signals) of the second frequency f. - v / 2 towards the radiators 1212. Because the U-shaped segments 1210 surround the radiators 1212, the U-shaped segments 1210 serve to isolate the two frequency bands. The structure and operation of the helical antenna of coupled segments for dual band 1220 is now described. Figure 13 is a diagram illustrating the distribution of current in segment 1210 and the radiator P1121 / 99MX 1212. In the illustrated embodiment, the radiator 1212 is? 2/4 and is fed from the first end 1232. Sections 1262, 1264, 1266 are a total of? 2 in length. The current in the radiator 1212 (illustrated by the distribution curve 1304) is coupled in the first section 1262. Because the total length of the sections 1262, 1264, 1266 is? 2, the remaining wave is folded around the segment. 1210 as illustrated by the current distribution curve 1308. Because the current in section 1262 is equal and opposite to the current in section 1264, these currents are canceled in the radiator 1208, effectively isolating the frequency radiation. /? x of the frequency v /? 2. In one embodiment, the double-band coupled segment helical antenna 1220 is implemented by using printed circuit card techniques or other similar techniques (a tape antenna). This embodiment is described in more detail with reference to Figures 14A and 14B. The helical antenna of coupled segments for double band tape mode consists of tape radiators 1204, 1212 recorded on a dielectric substrate. This substrate is a flexible, thin material that is wound into a cylindrical, conical or other suitable shape such that the radiators are wound helically (preferably symmetrically) with P1121 / 99MX with respect to the central axis of the form. Figures 14A and 14B illustrate the components used to manufacture a double-band coupled segment helical antenna 1220. Figures 14A and 14B present a view of a far surface 1400 and a close surface 1402 of a substrate, respectively. The double-band coupled segment helical antenna 1220 ines a radiator portion 1404 a first feed portion 1406 and a second feed portion 1408. For analysis purposes, the radiator portion 1404 has a first end 1232 adjacent to the portion of feed 1408 and a second end 1434 adjacent feed portion 1406 (at the opposite end of radiator portion 404). In the embodiments described and illustrated herein, the antennas are described as being made by shaping the substrate into a cylindrical, conical or other suitable shape with the near surface that is on the outer surface of the formed cylinder. In alternative embodiments, the substrate is shaped in the proper manner with the far surface being on the external surface of the form. In one embodiment, the dielectric substrate is a thin, flexible layer of polytetrafluoroethanol (PTFE), a PTFE / glass composite, or other dielectric material P1121 / 99MX as provided in the conventional helical antennas described above. In the embodiment illustrated in Figures 14A and 14B, the supply network 1272 is recorded on the feed portion 1406 on the far surface 1400. That is, the traces of the signal for the supply network 1272 are recorded on the far surface 1400 of the feed portion 1406. A land plane 1476 is provided for the feed network 1272 on the near surface 1402 of the feed portion 1406. The feed network 1274 is recorded on the feed portion 1408 on the nearby surface 1402 A land plane 1478 is formed for the supply network 1274 in the feed portion 1408 of the far surface 1400. In the illustrated embodiment, the segments 1208 consist of two components or sections, the section 1208B deposited on the far surface 1400 and the section 1208C deposited on the near surface 1402. The point at which the segments 1208A and 1208B meet is the feeding point for the radi 1204. A power line 1208A is used to transfer signals to and from the radiator segment 1208 at the end of the radiator section 1208B on the far surface 1400. The length by which the power line P1121 / 99 X 1208A, 'the, reception,' extends from the terrestrial flag 1476, 'is selected to perfect the equal impedance of the antenna for the supply network 1272. The length of the power supply line 1208A it is selected to be slightly larger than the radiator section 2108C. Specifically, in one embodiment, this is 2.5 mm (0.01 inches) shorter than the 1208A power line, such that there is an opening between the ends of the radiator sections 1208B and 1208C in which the 1208A power line crosses or extends over them. In the illustrated embodiment, the radiators 1212 consist of two components or sections, the section 1212B deposited on the far surface 1402 and the section 1212C deposited on the far surface 1402. The point at which the segments 1212B and 1212C meet is the point 1212A power supply for the radiator 1212A is used to transfer the signals to and from the radiator segment 1212 at the end of the radiator section 1212B at the near surface 1402. The power lines 1208A and 1212A are generally arranged on the substrate such that they are opposite and substantially centered on the radiator sections 1208C and 1212C, respectively. While the position of the power lines 1208A and 1212A on the land planes 1476 and 1478 can P1121 / 99MX follow the angle of the radiator sections 1208C and 1212C, respectively, this is not a condition and can be connected to the supply networks 1272 and 1274 at a different angle, as shown in Figure 15. Figure 15 is a diagram that effectively illustrates figures 14A and 14B superimposed one upon the other. Figure 15 illustrates how the components or sections 1208B, 1208C overlap the feed line 1208A and how the sections 1212B, 1212C overlap the feed line 1212A. Figure 16 is a diagram illustrating an exemplary schematic distribution of a helical antenna of coupled dual band segments, according to one embodiment of the invention. Note that in the illustrated embodiment, the U-shaped segment 1210 extends beyond the length of the radiators 1212. In this embodiment, the U-shaped segment 1210 can be described as having two parts. A first part consists of two adjacent sections 1610A, 1610B deposited on the substrate and separated by a width that is sufficient to accommodate the radiator 1212. A second part of the segment 1210 extends beyond the first part and also consists of two adjacent sections 1610C, 1610D. However, in the illustrated embodiment, these sections 1610C, 1610D are separated so that they remain P1121 / 99MX more together than sections 1610A, 1610B and preferably could not accommodate the deposition of radiator 1212 therebetween. As a result of the illustrated structure, segments 1208, 1210 overlap each other without having segment 1208 superimposed on radiator 1212. Note also that due to this structure, the interleaving of segments 1208, 1210 occurs over a portion of segment 1210 that it is narrower, thus decreasing the diameter of the antenna. Figure 17 illustrates an example of a mode where the U-shaped segments 1210 are asymmetric. In this embodiment, the U-shaped segment 1210 does not extend all the way to the feeding portion in both sections. Here, segments 1610A, 1610C and 1610D are again used without the extension of segments 1212A, 1212B or 1212C in the region surrounded by segments 1610C and 1610D. In this embodiment, segment 1610C is omitted for each portion of radiator 1210. An advantage of the embodiments illustrated in FIGS. 16 and 17 is that for a specific radiator portion width, the width of segment 1210 can be increased. In this way, the embodiment illustrated in Figure 17 can offer tape width operation P1121 / 99MX increased for the second frequency. The prior description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. The various modifications of these modalities will be readily apparent to those skilled in the art without the use of the inventive faculty. In this way, the present invention is not intended to be limited to the embodiments shown herein, but will be in accordance with the broadest scope compatible with the principles and novel features described herein.

P1121 / 99MX

Claims (10)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following CLAIMS is claimed as property; A helical antenna for dual band comprising a portion of radiator having a first set of one or more radiators and a second set of one or more radiators, a radiator of the first set of radiators comprising: a first radiator segment which extends in a helical form from the second end of the radiator portion towards the first end of the radiator portion; and a U-shaped radiator segment extending in a helical shape from the first end of the radiator portion to the second end of the radiator portion; and a radiator of the second set of radiators comprising: a third segment disposed within the U-shaped segment; whereby the first set of radiators resonates at a first frequency and the second set of P1121 / 99MX radiators resonates at a second frequency thus providing dual band operation.
2. 2. The helical antenna according to the claim 1, wherein the radiator segments consist of tape segments deposited on a dielectric substrate, wherein the dielectric substrate is configured in such a way that the radiators are wound in a helical manner.
3. 3. The helical antenna according to the claim 2, wherein the dielectric substrate is formed into a cylindrical shape or a conical shape. The helical antenna according to claim 1, wherein the U-shaped radiator segment comprises: a first section extending from the first end of the radiator portion towards the second end of the radiator portion; a second section adjacent to the first portion and extending from the second end towards the first end of the radiator portion; and a third section connecting the first portion and the second portion. The helical antenna according to claim 1, wherein the U-shaped radiator segment comprises: a first part comprising two first P1121 / 99MX sections extending from the first end of the radiator portion to the second end of the radiator portion, wherein the first two sections are separated by a width such that the third segment may be disposed therebetween; and a second part comprising two second sections extending from the first two sections and separating at "a width that is narrower than the width of the first sections" 6. The helical antenna according to claim 1, wherein the U-shaped radiator segment is asymmetric. 7. The helical antenna according to claim 1, wherein the first segments are? X / 4 in length, where? is the wavelength of a resonant frequency of the anten. The helical antenna according to claim 1, wherein the combined length of the sections of the second segment is? L t where? ^^ is the wavelength of a resonant frequency of the antenna. The helical antenna according to claim 1, wherein each of the first and second sets of radiators consists of four radiators and the antenna further comprises a supply network for each of the first and second sets of radiators. P1121 / 99MX 10. The helical antenna according to claim 1, further comprising a feed point for each radiator of the first set of radiators, the feed point is positioned at a distance from the second end along the first segment, in where the distance is selected to equalize the impedance of the radiator with a supply network. P1121 / 99MX SUMMARY OF THE INVENTION A helical antenna with coupled segments for dual band or dual band operating in two frequency bands is provided. The helical antenna with dual band coupled segments (1200) includes a radiator portion (1202) having two sets of one or more helically wound radiators (1204)., 1212) extending from one end (1234) of the radiator portion (1202) to the other end (1232) of the radiator portion (1202). The radiators of the first set of radiators (1204) comprise two segments: a first radiator segment (1208) extending helically from one end of the radiator portion (1202) to the other end of the radiator portion (1202). ); and a second radiator segment (1210) that is U-shaped and extends helically from the first end of the radiator portion (1202) to the second end of the radiator portion (1202). The radiators of the second set of radiators (1212) comprise a radiator (1212) disposed or located within the U-shaped segment (1210). The first set of radiators (1204) resonates at a first frequency and the second set of radiators (1212) resonates at a second frequency thereby providing a dual band or dual band operation, with a P1121 / 99 X minimum coupling between the frequency bands. P1121 / 99MX