Vehicle-mounted communication antenna

Abstract

The invention relates to the technical field of vehicle-mounted antennas, and discloses a vehicle-mounted communication antenna which is mainly composed of a bottom plate, a base, a UHF low-frequency antenna element, a substrate plate, a main conductor radiation patch array and a reflection conductor radiation patch array, the main conductor radiation patch array comprises a feed-in part and a radiation part, the feed-in part comprises a first feed-in connecting part, and the radiation part comprises a second feed-in connecting part. The two ends of the first feed-in connecting part are symmetrically connected with second feed-in connecting parts, the reflection conductor radiation patch array comprises a feed-in part and a radiation part, the feed-in part comprises the first feed-in connecting part, and the two ends of the first feed-in connecting part are symmetrically connected with the second feed-in connecting parts. And the center of the main conductor feed-in connecting part I and the center of the reflection conductor feed-in connecting part I are respectively connected with the probe of the coaxial feed element and the metal conducting layer. According to the antenna structure, different radiation patches are designed, the radiation bodies are asymmetrically arranged, and ports are physically isolated, so that the characteristics of linear gain, omnidirectional high gain and high isolation can be met at the same time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle-mounted antennas, in particular to a vehicle-mounted communication antenna. BACKGROUND

[0002] Currently, the demand for communication bandwidth, signal quality and multi-scene adaptability in the automotive industry continues to increase, especially with the popularization of 5G technology and the landing of vehicle-road cooperation (V2X) applications, requiring vehicle-mounted antennas to have wider working frequency bands, higher gain, better omnidirectional coverage capability and lower inter-antenna interference to meet the real-time data interaction needs in complex driving environments.

[0003] In the existing technical field of vehicle-mounted communication antennas, the mainstream scheme still has many performance bottlenecks, which are difficult to match the growing communication needs. For example, the technical scheme proposed in the published patent "Multi-band vehicle-mounted communication antenna (ZL202010174463.5)" has significant frequency-dependent gain performance - only in the high frequency band above 4GHz can it reach 5dB, while in the low frequency band below 2.5GHz, the gain is greatly attenuated to about 1.5dB, and the low frequency band gain fluctuates significantly, resulting in vehicle communication (such as traditional cellular network signals) in weak signal areas such as rural areas and tunnels. prone to interruption or delay. Another published patent "5G full-band vehicle-mounted antenna and shark fin antenna device (ZL202322237151.6)" attempts to cover the 5G frequency band, but its gain characteristics are also limited to the high frequency region, only achieving 5dB gain in the frequency band above 2.5GHz, and the low frequency band gain nonlinearity problem is prominent, and there is no special optimization for the isolation between multiple antenna elements.

[0004] In summary, the existing vehicle-mounted communication antenna technology scheme usually has low gain, no special optimization for isolation, poor omnidirectional gain, and gain nonlinearity. Another disadvantage caused by the above problems is that the antenna has poor actual use effect during operation. SUMMARY

[0005] To solve the above technical problems in the related art, the present application provides a vehicle-mounted communication antenna that can solve the above problems.

[0006] To achieve the above technical purposes, the technical scheme of the present application is as follows: A vehicle-mounted communication antenna comprises a base plate, a UHF low-frequency antenna element is installed in the middle of the upper end surface of the base plate, a seat is installed on the left and right sides of the upper end surface of the base plate respectively, a substrate plate is vertically inserted into the seat, a main conductor radiation patch array and a reflection conductor radiation patch array are respectively arranged on the two side surfaces of the substrate plate, the main conductor radiation patch array comprises a main conductor feed-in part and a main conductor radiation part, the main conductor feed-in part comprises a one-character type main conductor feed-in connecting part one, the two ends of the main conductor feed-in connecting part one are symmetrically connected with a seven-character type main conductor feed-in connecting part two, the reflection conductor radiation patch array comprises a reflection conductor feed-in part and a reflection conductor radiation part, the reflection conductor feed-in part comprises a one-character type reflection conductor feed-in connecting part one, the two ends of the reflection conductor feed-in connecting part one are symmetrically connected with a seven-character type reflection conductor feed-in connecting part two, the center of the main conductor feed-in connecting part one and the center of the reflection conductor feed-in connecting part one are respectively connected with the probe of a coaxial feed element and a metal conductive layer, and the patch width of the reflection conductor feed-in part gradually narrows from the center of the reflection conductor feed-in connecting part one to the distal end.

[0007] Further, the front and rear sides of the upper end surface of the seat are respectively provided with a connecting block one and a connecting block two, and the connecting block one and the connecting block two are respectively provided with an installation slot one and an installation slot two matched with the substrate plate.

[0008] Further, the substrate plate is made of TU865 plate material with a dielectric constant of 4.3, a loss tangent angle of 0.01 and a magnetic permeability of 1.

[0009] Further, the included angle between the two substrate plates is 10°, and the included angle between the substrate plate and the vertical bisector of the base plate is 5°.

[0010] Further, the UHF low-frequency antenna element is a 400 MHz low-frequency antenna, and the UHF low-frequency antenna element is a cylindrical structure.

[0011] Further, the side surface of the substrate plate close to the UHF low-frequency antenna element is provided with the reflection conductor radiation patch array, and the side surface of the substrate plate away from the UHF low-frequency antenna element is provided with the main conductor radiation patch array.

[0012] Further, the patch width of the main conductor feed-in part is constant, and the main conductor radiation part comprises a T-shaped main conductor radiation subpart one and a one-character type main conductor radiation subpart two vertically connected to the end of the main conductor feed-in connecting part two.

[0013] Further, the reflection conductor radiation part comprises a T-shaped reflection conductor radiation subpart one and a one-character type reflection conductor radiation subpart two vertically connected to the end of the reflection conductor feed-in connecting part two.

[0014] Further, the coaxial feed element comprises a cylindrical feed body, an outer sidewall of the feed body is provided with a metal conductive layer, one end surface of the feed body is provided with a probe, the reflection conductor radiation patch is connected with the metal conductive layer of the coaxial feed element, and the main conductor radiation patch is connected with the probe of the coaxial feed element.

[0015] The application has the advantages that the antenna structure can meet the requirements of linear gain, omnidirectional high gain and high isolation by designing different radiation patches, using asymmetric arrangement of the radiation body and physically isolating the ports. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0017] The present application will be further described in detail below according to the drawings.

[0018] Figure 1 is a structural schematic diagram of a vehicle-mounted communication antenna according to an embodiment of the present application; Figure 2 is an exploded view of a vehicle-mounted communication antenna according to an embodiment of the present application; Figure 3 is a top view of a vehicle-mounted communication antenna according to an embodiment of the present application; Figure 4 is a structural schematic diagram of the connection of a main conductor radiation patch, a reflection conductor radiation patch and a coaxial feed element according to an embodiment of the present application; Figure 5 is a plan view of a reflection conductor radiation patch according to an embodiment of the present application; Figure 6 is a surface current distribution diagram of a reflection conductor radiation patch according to an embodiment of the present application; Figure 7 is a plan view of a main conductor radiation patch according to an embodiment of the present application; Figure 8 is a far-field directional diagram obtained by the single radiation of a radiation body of a feed port one according to an embodiment of the present application; Figure 9 is a far-field directional diagram obtained by the single radiation of a radiation body of a feed port two according to an embodiment of the present application; Figure 10 is a far-field directional diagram obtained by the simultaneous radiation of two radiation bodies of a feed port one and a feed port two according to an embodiment of the present application; Figure 11 This is the reflection coefficient frequency curve (S-parameter amplitude-frequency diagram) of antenna feed ports one and two as described in the embodiment of the present invention. Figure 12 This is the amplitude-frequency curve (crosstalk suppression curve) of the S21 parameter between the dual-feed ports of the antenna described in this embodiment of the invention. Figure 13 This is the amplitude-frequency curve (crosstalk suppression curve) of the S12 parameter between the dual-feed ports of the antenna described in this embodiment of the invention. Figure 14 This is the gain-frequency curve of the vehicle-mounted communication antenna described in the embodiment of the present invention.

[0019] In the picture: 1. Base plate; 11. Vertical bisecting plane; 2. UHF low-frequency antenna element; 3. Base; 4. Substrate; 5. Main body radiating patch array; 51. Main body feed section; 511. Main body feed connection section one; 512. Main body feed connection section two; 52. Main body radiating section; 521. Main body radiating section one; 522. Main body radiating section two; 6. Reflector radiating patch array; 61. Reflector feed section; 611. Reflector feed connection section one; 612. Reflector feed connection section two; 62. Reflector radiating section; 621. Reflector radiating section one; 622. Reflector radiating section two; 7. Coaxial feed element. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0021] like Figures 1-2 As shown, this invention discloses a vehicle-mounted communication antenna. The overall appearance is U-shaped, with dimensions of 350mm × 100mm × 21mm. The main body consists of a base plate 1, a base 3, a UHF low-frequency antenna element 2, a substrate 4, a metal-structured main body radiating patch array 5, and a metal-structured reflective conductor radiating patch array 6. The thickness of both the main body radiating patch array 5 and the reflective conductor radiating patch array 6 is 0.01mm. The substrate 4 is made of TU865 material with a dielectric constant of 4.3, a loss tangent of 0.01, and a permeability of 1. The UHF low-frequency antenna element 2 is a 400 MHz low-frequency antenna with a cylindrical structure. Figure 3As shown, the two outer antenna radiating structures, composed of two substrates 4 and their radiating patches, are arranged non-parallel on the base 1. The two antenna radiating structures complement each other during radiation to meet the requirement of omnidirectional high gain. The UHF low-frequency antenna element 2 is located between the two antenna radiating structures. In addition to its communication function, the UHF low-frequency antenna element 2 also improves the isolation between the antennas by setting physical barriers in the two antenna radiating structures.

[0022] Example 1: like Figure 4 The diagram shows the structure of the main conductor radiating patch, the reflective conductor radiating patch, and the coaxial feed element. The main conductor radiating patch array 5 and the reflective conductor radiating patch array 6 on both sides of the substrate 4 are fed by the coaxial feed element 7. The energy of the reflective conductor radiating patch array 6 is conducted by the outer metal conductive layer of the coaxial feed element 7, and the energy of the main conductor radiating patch array 5 is conducted by the probe of the coaxial feed element 7.

[0023] like Figure 5 As shown, the width of the reflector feed section 61 gradually narrows from the center of the reflector feed connection section 611 to the far end. At the wider part of the patch, its equivalent impedance is lower. As it gradually narrows to the far end, the impedance increases accordingly. This width change process is equivalent to an impedance transformer. This design can improve the problem of high matching requirements for antennas at high frequencies.

[0024] If the input impedance of the antenna does not match the impedance of the feed line, it will cause signal reflection, thus affecting the actual performance of the antenna. The reflection coefficient can be expressed as:

[0025] Z in Z0 is the antenna input impedance, and Z0 is the transmission line characteristic impedance. Compared to ordinary transmission lines, the antenna in this application, by continuously changing the linewidth (feed section 61 of the reflective conductor), allows the impedance to smoothly transition from the feed patch end to the radiating patch end. This improves the transmission line return loss by approximately 20%, thereby avoiding excessive reflection at the transition point and maintaining a low reflection coefficient over a wider frequency band. The impedance bandwidth is improved by approximately 15%, which helps to extend the antenna's operating bandwidth. Furthermore, this design can optimize current distribution to a certain extent, improve radiation characteristics, and allow energy to be coupled more smoothly into free space, thus being more conducive to achieving high gain. Figure 6 The diagram shows the surface current distribution of the reflective conductor radiating patch. The surface current of the reflective conductor radiating patch array 6 gradually increases with the decrease of width at the transition point of the transmission line (reflective conductor feed part 61). The conduction of the antenna surface current as designed indicates that the fed energy is well converted, the antenna radiation characteristics are improved, and the energy is coupled to free space more smoothly.

[0026] like Figure 7 The diagram shows a main conductor radiating patch structure, whose transmission line (main feed section 51) differs from that of a reflective conductor radiating patch. Due to the change in operating frequency, the main conductor radiating patch is relatively larger, resulting in better input impedance matching at the feed point, thus eliminating the need for gradual matching. Furthermore, the fabrication process using a constant-width transmission line is relatively simple. While ensuring dual-band antenna performance, the patch design of this antenna scheme balances performance, cost, and fabrication requirements.

[0027] Example 2: like Figure 3 As shown, the included angle between the two substrates 4 is 10°, and the included angle between the substrate 4 and the perpendicular bisector 11 of the base plate 1 is 5°. That is, the two substrates 4 are placed on the base 3 of the base plate 1 at ±5°. This design can better radiate energy into omnidirectional space. Figure 3 Based on the central arrangement, the coaxial feed element 7 on the right is designated as feed port one, and the coaxial feed element 7 on the left is designated as feed port two, as follows. Figure 8 and Figure 9 The images shown are horizontal cross-sections of the far-field radiation patterns obtained by individual radiation from two radiators (a substrate 4 and its dominant radiating patch array 5 and reflective conductor radiating patch array 6 forming a radiator) at feed ports one and two, respectively. It can be seen that the far-field radiation pattern obtained by a single radiator has relatively poor omnidirectionality. Figure 10 As shown, when the two radiators radiate simultaneously, the all-directional gain consistency of the far-field pattern is significantly improved. The two radiators exhibit a certain degree of complementarity in their radiation directions, thus greatly improving the omnidirectional coverage of the far-field pattern. In addition to its excellent improvement in directional coverage, this design also demonstrates a good effect in gain enhancement. The gain obtained by feeding each of the first and second feed ports individually is 5.56 dBi, while the gain obtained after superposition using digital synthesis technology is 6.99 dBi, representing a gain improvement of more than 1 dBi.

[0028] like Figure 11 As shown, the reflection coefficient bandwidth of the feed ports one and two of the vehicle-mounted communication antenna of this application can achieve 824.2MHz-879.2MHz@-10dB and 1765MHz-1880MHz@-5.5dB. Figure 12 and Figure 13The diagrams S21 (signal transmission coefficient amplitude-frequency curve of "feed port one → feed port two") and S12 (signal transmission coefficient amplitude-frequency curve of "feed port two → feed port one") of the vehicle-mounted communication antenna of this application, respectively, can achieve high isolation of 400MHz-470MHz@-30dB, 824.2 MHz-879.2 MHz@-15 dB, and 1765 MHz-1880MHz@-19.5dB. The vehicle-mounted communication antenna of this application, through physical isolation and optimized arrangement, greatly improves the isolation between antennas. In multi-antenna systems, coupling between antennas can cause crosstalk, the magnitude of which is determined by S... 12 Or S 21 express:

[0029] Where Isolation (dB) represents isolation, referring to the degree of signal attenuation from the output to the input. 12 This indicates how much of the signal leaks or couples to the first feeder port when a matching load is connected to the first feeder port and a signal is input to the second feeder port.

[0030] Higher isolation indicates lower mutual coupling. Compared to existing vehicle-mounted communication antennas, improved isolation reduces mutual coupling interference between antennas, thereby enhancing the stability and robustness of the communication system. Furthermore, good isolation helps increase the system's communication capacity, data transmission rate, and gain stability.

[0031] Figure (14) shows the gain-frequency curve of the vehicle-mounted communication antenna of this application. The antenna gain of this application has the characteristic of linear gain, that is, the antenna gain increases with increasing frequency. The directivity and efficiency of the antenna determine the gain:

[0032] in This refers to the directional gain of the antenna. Antenna directivity coefficient, , , These represent the antenna's elevation angle, azimuth angle, and radiation efficiency in spherical coordinates, respectively.

[0033] In most existing antenna designs, the antenna gain is nonlinear, which may affect communication quality in practical applications.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-mounted communication antenna, characterized in that, The base plate (1) is provided with a UHF low-frequency antenna element (2) installed in the middle of the upper surface of the base plate (1). A base (3) is installed on the left and right sides of the upper surface of the base plate (1). A substrate plate (4) is vertically inserted into the base (3). A main body radiating patch array (5) and a reflective conductor radiating patch array (6) are provided on the two sides of the substrate plate (4). The main body radiating patch array (5) includes a main body feed section (51) and a main body radiating section (52). The main body feed section (51) includes a straight main conductor feed connection section (511). The two ends of the main body feed connection section (511) are symmetrically connected with a figure-7 main conductor feed connection. Part 2 (512), the reflective conductor radiation patch array (6) includes a reflective conductor feed section (61) and a reflective conductor radiation section (62). The reflective conductor feed section (61) includes a line-shaped reflective conductor feed connection section 1 (611). The two ends of the reflective conductor feed connection section 1 (611) are symmetrically connected to a figure-7-shaped reflective conductor feed connection section 2 (612). The center of the main body feed connection section 1 (511) and the center of the reflective conductor feed connection section 1 (611) are respectively connected to the probe of the coaxial feed element (7) and the metal conductive layer. The width of the reflective conductor feed section (61) gradually narrows from the center of the reflective conductor feed connection section 1 (611) to the far end.

2. The vehicle-mounted communication antenna according to claim 1, characterized in that, The base (3) has a connecting block 1 and a connecting block 2 on the front and rear sides of its upper surface, respectively. The connecting block 1 and the connecting block 2 are respectively provided with mounting slot 1 and mounting slot 2 that are compatible with the substrate plate (4).

3. The vehicle-mounted communication antenna according to claim 1, characterized in that, The substrate (4) is made of TU865 material with a dielectric constant of 4.3, a loss tangent of 0.01, and a permeability of 1.

4. The vehicle-mounted communication antenna according to claim 1, characterized in that, The included angle between the two substrate plates (4) is 10°, and the included angle between the substrate plate (4) and the perpendicular bisector (11) of the base plate (1) is 5°.

5. A vehicle-mounted communication antenna according to claim 1, characterized in that, The UHF low-frequency antenna element (2) is a 400 MHz low-frequency antenna, and the UHF low-frequency antenna element (2) has a cylindrical structure.

6. A vehicle-mounted communication antenna according to claim 1, characterized in that, The substrate (4) has a reflective conductor radiating patch array (6) on the side closest to the UHF low-frequency antenna element (2), and a main body radiating patch array (5) on the side away from the UHF low-frequency antenna element (2).

7. A vehicle-mounted communication antenna according to claim 1, characterized in that, The width of the main body feed section (51) is constant, and the main body radiation section (52) includes a T-shaped main body radiation section one (521) and a straight main body radiation section two (522) that are vertically connected to the end of the main body feed connection section two (512).

8. A vehicle-mounted communication antenna according to claim 1, characterized in that, The reflective conductor radiating section (62) includes a T-shaped reflective conductor radiating section one (621) and a straight reflective conductor radiating section two (622) that are vertically connected to the end of the reflective conductor feed connection section two (612).

9. A vehicle-mounted communication antenna according to claim 1, characterized in that, The coaxial feed element (7) includes a cylindrical feed body, the outer side wall of the feed body is provided with a metal conductive layer, one end face of the feed body is provided with a probe, the reflective conductor radiation patch array (6) is connected to the metal conductive layer of the coaxial feed element (7), and the main body radiation patch array (5) is connected to the probe of the coaxial feed element (7).

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