CN1365161A - multi-frequency antenna device - Google Patents

Abstract

A multi-frequency antenna device is prepared as forming the first radiation unit by a zigzag extended antenna with the first frequency band and the second radiation unit by a second frequency band, connecting the first radiation unit and the second radiation unit to each other by feed-in radiation unit with two ends, using signal feed-in end as one end and connecting the first radiation unit and the second radiation unit to each other by another end.

Description

multi-frequency antenna device

The present invention relates to an antenna device (antenna), in particular, to a multi-frequency antenna device (antenna operable in multiple frequency bands), which is commonly used in wireless communication transmission equipment (wireless communication device).

In recent years, personal mobile wireless (wireless) communication transmission devices have rapidly increased and become popular. In order to provide consumers with multi-functional wireless communication services, dual-frequency (two frequency bands) or multi-frequency mobile phone module design has become a trend, and the antenna part responsible for signal transmission and reception must also have dual-frequency or multi-frequency characteristics. In terms of appearance, mobile phone antennas can be divided into hidden and non-hidden.

Most non-hidden mobile phone antennas use wire antennas combined with helix antennas to achieve dual-band purposes. In the literature of US Pat. No. 5,926,139, an antenna structure with at least two frequencies is disclosed, as shown in FIG. 1a and FIG. 1b. The antenna structure includes a first antenna element, P2 or P3, and a second antenna element, HX3 or HX4. The first antenna element, P2 or P3, is preferably a straight conductor and the second antenna element, HX3 or HX4, is preferably a conductor wound into a cylindrical coil. The antenna structure 100 has different resonance frequencies. The rod antenna element, P2 or P3, is partially housed in the helical antenna element, HX3 or HX4, and both may contain the same feed point A4, or Separate feed points, A5 and A6. The antenna structure 100 may include a third antenna element (not shown in the figure), the third antenna element preferably has a different resonant frequency from the other two antenna elements and is meandered into a cylindrical coil conductor.

This non-concealed mobile phone antenna structure is used on a mobile phone, and the phone is used in a variety of mobile phone systems using different frequencies. However, this antenna structure needs to be assembled outside the casing of the mobile phone, and the protruding antenna part is likely to be damaged due to user's negligence.

However, the hidden mobile phone antenna is based on the planar inverted F-antenna (planar inverted F-antenna) as its main design principle. In the literature of US Patent 6,054,966, a single planar antenna for dual frequency is disclosed, as shown in FIG. 2 . This planar antenna includes a first radiating portion (radiating portion) 202 and a second radiating portion 204 for dual frequency, the first radiating portion 202 and the second radiating portion 204 are made of a conductive material layer 206 A connecting portion 208 connects it and separates it from a ground plane 210 of conductive material. Each radiation portion is formed on the conductive material layer 206 by a planar inverted-F antenna. A preferred conductive material layer is a metal sheet. The grounding pin (grounding pin) 212 connects the connection part 208 and the ground plane 210 to each other, and a single feed pin (single feed pin) connects the connection part 208 to the input/output port (input/output port) of the transceiver circuit (transceivercircuitry). ). The single planar antenna 200 utilizes the design of slits on the planar metal patch, so that the antenna can have dual-band effects.

However, the disadvantage of this hidden mobile phone antenna is that when the planar metal sheet shrinks, its bandwidth will also be reduced, and it is not easy to balance the size and bandwidth at the same time.

The purpose of the present invention is to provide a multi-frequency antenna device, which can overcome the shortcomings of traditional mobile phone antennas, and has multiple advantages such as double resonance frequency, broadband and concealment, and can be applied to personal wireless communication devices, such as mobile phones, etc. , Short-range wireless communication devices, such as home wireless phones, and wireless local area network communication equipment.

The multi-frequency antenna device of the present invention includes a first radiating element, a second radiating element, and a feeding radiating element. The first radiating unit is made of a conductive material, and is formed by an antenna with a bend wire extension type, and is equipped with a first frequency band (frequency band) to control the characteristics of the first frequency band of the antenna; the second The radiating unit is a conductive material, and is formed by an antenna with a second frequency band, which is used to control the characteristics of the second frequency band of the antenna; the feeding radiating unit has at least two ends, and one end is used as a signal feeding end , so that the signals of the first frequency band and the second frequency band share the same feed, and the other end connects the first radiating unit and the second radiating unit to form a top loaded structure.

According to the present invention, the multi-frequency antenna device utilizes the top-loaded structure combined with the design of the zigzag antenna to achieve multiple purposes such as dual resonance frequency (dual resonance frequency), broadband and concealment.

The purpose of the meander antenna is to effectively reduce the overall size of the antenna; the purpose of the top-loaded structure is to change the extension direction of the antenna so that it can be completely placed in the case of the mobile phone to achieve a hidden effect; in addition, the price is low It is also another object of the multi-frequency antenna device of the present invention. Moreover, since the antenna device can be made of common materials, its material and manufacturing costs can be greatly reduced, which is very suitable for mass production and has strong market competitiveness.

In an embodiment of the present invention, the zigzag antenna of the first radiating unit is a metal wire extending in a variety of zigzag shapes such as a square wave, a sawtooth, and a sinusoid, and is used to control The low-frequency band characteristics of this antenna shorten the overall length of the antenna. The central frequency and bandwidth of the antenna can be adjusted by controlling the length of the meandering metal wire and the number of times of meandering. The antenna of the second radiating unit adopts a straight-line extended metal wire segment, and the characteristics of the high-frequency band of the antenna are controlled by changing the length and width of the metal wire segment. In addition, the metal line segment can also be implemented in a meandering and extending manner.

In addition, when used in personal mobile communication transmission equipment, the feeding and radiating unit of the multi-frequency antenna device of the present invention has three preferred implementation modes. One is a metal wire without a base; the other two are metal wires with a base, and the metal wires are respectively placed on the surface and inside of the base. Similarly, antennas in two different frequency bands can also be implemented in three manners. One is a bimetallic wire without a substrate; the other two are bimetallic wires with a substrate. The metal wires are respectively placed on the surface and inside of the substrate, and the two metal wires can be distributed on different levels. In addition, the surface on which the bimetal wires are distributed can be a plane or a curved surface.

The measurement results of the antenna return loss (return loss) characteristics of the multi-frequency antenna device of the present invention are analyzed using a dual-frequency antenna embodiment and a commercial triple-frequency antenna embodiment. The operating range of the dual-band antenna is designed in the GSM900 and DCS800 frequency bands, and its -10dB bandwidth is 130MHz and 230MHz respectively. The high-frequency range of commercial tri-band antennas can even include two frequency bands of DCS1800 and PCS1900.

In conjunction with the detailed description of the following drawings, embodiments and scope of patent application, the above and other purposes and advantages of the present invention are described in detail below, wherein:

1a and 1b are schematic diagrams of a conventional antenna structure for at least two frequencies.

FIG. 2 is a schematic diagram of another conventional single planar antenna for dual frequency.

FIG. 3 is a schematic diagram of a preferred embodiment of the multi-frequency antenna device of the present invention.

4a-4c respectively show three implementations of the antenna of the first radiating unit and the antenna of the second radiating unit according to the present invention.

Figures 5a-5c respectively show three implementations of feeding into the radiation unit according to the present invention.

FIG. 6 is an assembly method in which the multi-frequency antenna device and a printed circuit board of the present invention are applied in a mobile phone case by using the embodiments of FIG. 4a and FIG. 5a.

7a-7c are three implementations of meandering extension of the meandering antenna of the first radiating unit according to the present invention.

FIG. 8 illustrates measurement results of antenna return loss characteristics of an embodiment of a dual-band antenna according to the present invention.

FIG. 9 illustrates the measurement results of the antenna return loss characteristic of an embodiment of a tri-band antenna according to the present invention.

FIG. 3 is a schematic diagram of a preferred embodiment of the multi-frequency antenna device of the present invention. As shown in FIG. 3 , the multi-frequency antenna device 300 includes a first radiating unit 302 , a second radiating unit 304 , and a feeding radiating unit 300 . The first radiating unit 302 is formed with a zigzagging antenna with a first frequency band, and is used to control the characteristics of the first frequency band of the antenna; the second radiating unit 304 is formed with an antenna with a second frequency band The antenna is formed to control the characteristics of the second frequency band of the antenna; this feeding radiation unit 306 is equipped with two ends, and one end is used as a signal feeding end 308, so that the signals of the first frequency band and the second frequency band share the same feeding One end 308 and the other end 310 electrically connect the first radiating unit 302 and the second radiating unit 304 to form a top-loaded structure. The top-loaded structure changes the extension direction of the antenna so that it can be completely placed in the casing of the mobile phone to achieve a hidden effect.

According to the invention, the first frequency band is different from the second frequency band. Moreover, the first radiating unit 302 , the second radiating unit 304 , and the feeding radiating unit 306 are all made of conductive materials, such as metal materials.

4a-4c respectively show three implementations of the antenna of the first radiation unit 302 and the antenna of the second radiation unit 304 according to the present invention. In FIG. 4 a , the antenna of the first radiating unit 302 and the antenna of the second radiating unit 304 are substrate-less double metal wires 412 and 414 . In FIG. 4 b , the dual metal lines 412 and 414 are placed on the top surface 404 of a substrate 402 . In FIG. 4c, two sections of metal lines 412 and 414 are placed inside the substrate, and the two sections of metal lines are distributed on different levels _L1 and _L2 . According to the present invention, the surface on which the double metal wires 412 and 414 are distributed can be a plane or an arc, and the planes shown in FIG. 4b and FIG. 4c are flat.

Similarly, according to the present invention, there are three implementation modes for feeding into the radiation unit 306, as shown in Fig. 5a-Fig. 5c. FIG. 5 a shows the implementation in the form of metal lines 512 without a substrate; FIG. 5 c shows metal lines 512 placed in inner layer 506 of substrate 502 .

In the above-mentioned Fig. 4b and Fig. 4c and Fig. 5b and Fig. 5c, the base material is a dielectric such as ceramic material, FR4 plate and the like.

Figure 6 shows that the multi-frequency antenna device of the present invention and a printed circuit A schematic diagram of board 602 assembled in a mobile phone case. The included angle θ of the plane formed by feeding the radiating metal wire 512 and the double metal wires 412 and 414 can be a right angle, an acute angle or an obtuse angle, so as to avoid protruding antenna parts. A preferred general angle range is between 70 degrees and 180 degrees.

According to the present invention, the meander antenna of the first radiating unit 302 has multiple means of meandering and extending. Figures 7a-7c show three preferred implementations, which are square wave, sawtooth, and sinusoidal shapes, respectively. By utilizing the meandering extension method, the present invention can shorten the overall length of the antenna. Moreover, the zigzag extension of the first radiating unit 302 can also be formed by combining these zigzag shapes, and the curves of each zigzag shape can also use different periods. In addition, the central frequency and bandwidth of the antenna can be investigated by controlling the length of the meandering metal wire and the number of times of meandering. On the other hand, for the second radiating unit 304 (implemented with metal wires in the present invention) used to control the characteristics of the high-frequency band of the antenna, it is better designed in a straight line, by changing its length and width to adjust the center frequency and bandwidth of the antenna. In addition, this section of metal wire can also be implemented in a meandering and extending manner.

The present invention uses a dual-frequency antenna embodiment and a commercial triple-frequency antenna embodiment respectively to analyze the operational benefits of the multi-frequency antenna device of the present invention. The measurement results of the antenna return loss characteristics of these two embodiments are shown in Fig. 8 and Fig. 9 respectively, wherein, the abscissa represents the resonant frequency (unit is GHz) of the antenna, and the ordinate represents the value of the S-parameter S ₁₁ (unit price is dB), this parameter S ₁₁ describes the ratio of the RF power (radio frequency power, RF power) from the antenna port (antenna port) back to the feed circuit to the original feed power, that is, the return loss of the antenna.

In Fig. 8, the operating range of this dual-band antenna is designed in the GSM900 and DCS1800 frequency bands. When S ₁₁ is equal to -10dB, the bandwidths are 130MHz and 230MHz respectively, that is, from 841MHz to 971MHz, and from 1671MHz to 1901MHz. In this embodiment, the metal lines are fabricated on the surface of an FR4 substrate.

It can be seen from Figure 9 that the high-frequency range of this commercial tri-band antenna can even include the two frequency bands of DCS1800 & PCS (personal communication system) 1900.

It can be seen from the above that the multi-frequency antenna device of the present invention not only overcomes the shortcomings of traditional mobile phone antennas, but also has multiple advantages such as double resonance frequency, broadband and concealment, and can be applied to personal wireless communication devices, such as mobile phones, etc., for short-distance Wireless communication devices, such as home wireless phones, and wireless local network communication equipment.

However, what is described above is only a preferred embodiment of the present invention, and should not limit the implementation scope of the present invention. That is, all equivalent changes and modifications made according to the scope of the patent application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims (18)

1. A multi-frequency antenna device for wireless communication transmission equipment, characterized in that, the multi-frequency antenna device includes: A first radiating unit, the first radiating unit is made of a conductive material, and is formed with a meandering extension type and equipped with an antenna of a first frequency band to control the characteristics of the first frequency band: A second radiating unit, the second radiating unit is made of a conductive material and is formed by an antenna with a second frequency band for controlling the characteristics of the second frequency band, the first frequency band being different from the second frequency band ;as well as, A feed-in radiating unit, the feed-in radiating unit is equipped with at least two ends, one end is used as a signal feed-in end, so that the signals of the first frequency band and the second frequency band share the same feed-in, and the other end uses the first The radiating unit and the second radiating unit are interconnected and form a top-loaded structure. 2 . The multi-frequency antenna device according to claim 1 , wherein the feeding radiation unit is realized by using a metal conductor. 3 . 3 . The multi-frequency antenna device according to claim 1 , wherein the feeding radiating unit is realized by using a substrate made of a dielectric material and a metal conductor. 4 . 4. The multi-frequency antenna device according to claim 3, wherein the base has a top surface, and the metal conductor is placed on the top surface of the base. 5. The multi-frequency antenna device according to claim 3, wherein the base has an interior, and the metal conductor is placed in the interior of the base. 6 . The multi-frequency antenna device according to claim 1 , wherein the first radiating unit and the second radiating unit are realized by using a dielectric material substrate and a bimetallic conductor. 7. The multi-frequency antenna device as claimed in claim 6, wherein the base has a top surface, and the bimetallic conductor is placed on the top surface of the base. 8. The multi-frequency antenna device according to claim 6, wherein the base has an interior, and the bimetallic conductor is placed in the interior of the base. 9 . The multi-frequency antenna device according to claim 8 , wherein at least two layers are provided inside the substrate, and the bimetallic conductors are respectively placed on different layers inside. 10 . 10 . The multi-frequency antenna device according to claim 1 , wherein the first radiating unit and the second radiating unit share a same plane and have an included angle with the feeding radiating unit. 11 . 11. The multi-frequency antenna device according to claim 10, wherein the included angle is between 70 degrees and 180 degrees. 12. The multi-frequency antenna device according to claim 1, wherein the second radiating unit is placed on a curved surface. 13 . The multi-frequency antenna device according to claim 1 , wherein the first radiating unit uses a square-wave zigzag extension to shorten the overall length of the antenna. 14 . 14 . The multi-frequency antenna device according to claim 1 , wherein the first radiating unit uses a zigzag extension in a sawtooth shape to shorten the overall length of the antenna. 15 . 15 . The multi-frequency antenna device according to claim 1 , wherein the first radiating unit uses a sinusoidal extension in a sinusoidal shape to shorten the overall length of the antenna. 16 . 16. The multi-frequency antenna device according to claim 1, wherein the second radiation unit is a linear conductor. 17. The multi-frequency antenna device according to claim 1, wherein the second radiation unit is a meandering and extending conductor. 18. The multi-frequency antenna device according to claim 1, wherein the meandering extension of the first radiating element is shortened by using a combination selected from a square wave shape, a sawtooth wave shape, and a sine wave shape. The overall length of the antenna.

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