A dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios

Abstract

The present invention discloses a dual-polarized, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios, comprising a guiding assembly, a cross-dipole feed and a reflector. The guiding assembly comprises three equally spaced directors, each of which comprises a guiding main pole and a plurality of guiding units arranged on the guiding main pole, and each guiding unit comprises four antenna arms; the cross-dipole feed comprises a printed substrate, a floor, a support bar and two coaxial cables; a radiation assembly is printed on the surface of the printed substrate, and the upper and lower ends of the support bar are respectively connected to the printed substrate and the floor; the coaxial cable is passed through a pre-opened perforation in the floor and then connected to the printed substrate; the floor is fixed to the reflector. The above does not require an impedance transformer to achieve impedance conversion, effectively improving the problem of narrow bandwidth of traditional Yagi antennas.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communication systems, and in particular to a dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios. Background Art

[0002] With the large-scale commercialization of 5G, the use of 5G antennas has become widespread. However, many current communication systems only cover the 2G / 3G / LTE frequency bands, necessitating the addition of systems that include 5G antennas. Tunnel communication scenarios require narrow-beam, high-gain antennas for signal transmission. Therefore, developing narrow-beam, high-gain antennas for the 5G frequency band holds great promise. Existing Yagi antennas, with their simple structure and strong directivity, are widely used in various wireless communication systems and are also suitable for tunnel communication scenarios. However, existing Yagi antennas are generally single-polarized. To maximize spectrum utilization, dual-polarization is generally adopted to increase antenna channel capacity. The narrow bandwidth of traditional Yagi antennas severely limits their application in some communication environments, making coverage of the 14% (3.3GHz-3.8GHz) 5G frequency band a challenge. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a dual-polarization wide-bandwidth high-gain quasi-Yagi antenna for tunnel communication scenarios, which has the characteristics of dual polarization, high gain, narrow beam and simple structure.

[0004] To achieve the above-mentioned objectives, the solution provided by the present invention is a dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios, comprising a guiding assembly, a cross-dipole feed and a reflector, wherein the guiding assembly comprises three equally spaced directors, each of the directors comprising a guiding main pole and a plurality of guiding units arranged on the guiding main pole, and each guiding unit comprises four antenna arms; the cross-dipole feed comprises a printed substrate, a floor, a support bar and two coaxial cables, a radiation assembly is printed on the surface of the printed substrate, and the upper and lower ends of the support bar are respectively connected to the printed substrate and the floor; the coaxial cable is connected to the printed substrate after passing through a pre-opened hole in the floor; the floor is fixed on the reflector.

[0005] Furthermore, the four antenna arms are respectively arranged with the main pole as the center and extending in azimuths of 45°, 135°, 225°, and 315° in a clockwise direction, wherein the two antenna arms located at the 45° and 135° azimuths form a group, and the two antenna arms located at the 225° and 315° azimuths form a group.

[0006] Furthermore, the guiding units on the same guide are arranged at equal intervals along the length direction of the guiding main rod.

[0007] Furthermore, each of the antenna arms has a sheet-like structure.

[0008] Furthermore, the radiation component includes four radiation units arranged in a matrix, and the four radiation units are divided into a first dipole and a second dipole in a central vertical cross shape according to a diagonal relationship.

[0009] Furthermore, the two coaxial cables are connected to the feeding strips of the first dipole and the second dipole respectively.

[0010] Furthermore, each radiation unit is composed of a radiation ring and a radiation block, wherein the radiation ring is arranged adjacent to the periphery of the radiation block.

[0011] Furthermore, both ends of the reflective plate are bent upward to form reflective fences.

[0012] The beneficial effects of the present invention are: 1) the use of a cross-dipole feed enables the antenna to have dual polarization and wide bandwidth, expanding the channel capacity, and no impedance transformer is required to achieve impedance transformation, effectively improving the narrow bandwidth problem of the traditional Yagi antenna; 2) the antenna structure is stable; 3) by introducing a reflector to reflect electromagnetic waves, the antenna gain is improved, and good directional radiation characteristics are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of the Yagi antenna.

[0014] Figure 2 Schematic diagram of the structure of a single director.

[0015] Figure 3 Schematic diagram of the structure of the guidance unit.

[0016] Figure 4 Schematic diagram of the structure of the crossed dipole feed and reflector.

[0017] Figure 5 A top view of the crossed-dipole feed and reflector.

[0018] Figure 6 Schematic diagram of the structure of the reflector.

[0019] Figure 7 This is the S-parameter diagram of the antenna.

[0020] Figure 8 is the antenna gain diagram.

[0021] Figure 9 This is the directional pattern of 45° polarization.

[0022] Figure 10 This is the directivity pattern for -45° polarization.

[0023] Figure 11 The before-and-after diagrams for the two polarizations.

[0024] Among them, 11-director, 111-director main pole, 112-director unit, 2-cross dipole feed source, 21-printed substrate, 211-radiation unit, 212-first feeding hole, 213-second feeding hole, 214-jack, 22-floor, 23-support bar, 24-coaxial cable, 3-reflection plate, 31-reflection fence. DETAILED DESCRIPTION

[0025] To facilitate understanding of the present invention, a more comprehensive description of the present invention is provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention. It should be noted that the terms "first" and "second" in the present invention do not represent specific quantities or orders, but are merely used to distinguish between names.

[0026] In this embodiment, a dual-polarized wide-bandwidth high-gain quasi-Yagi antenna for tunnel communication scenarios includes a guiding assembly, a cross-dipole feed 2, and a reflector 3. The guiding assembly includes three equally spaced directors 11, each of which includes a guiding main pole 111 and seven guiding units 112 arranged on the guiding main pole 111. Each guiding unit 112 includes four antenna arms. Specifically, refer to the attached Figure 2 As shown, the four antenna arms of this embodiment are respectively arranged with the main pole 111 as the center and extending in azimuths of 45°, 135°, 225° and 315° in a clockwise direction, wherein the two antenna arms at the azimuths of 45° and 135° are a group, and the two antenna arms at the azimuths of 225° and 315° are a group, thereby forming a ±45° dual-polarization director 11 and also being able to achieve high gain characteristics of the antenna.

[0027] Furthermore, each antenna arm of this embodiment has a sheet-like structure, which not only retains the guiding performance of the director 11 but also simplifies the processing and can be obtained by cutting and stamping, thereby reducing costs.

[0028] In this embodiment, the cross-dipole feed source 2 includes a printed circuit board 21, a floor 22, two support bars 23, and two coaxial cables 24. The printed circuit board 21 is positioned above the floor 22, and a radiating component is printed on its surface. The radiating component includes four radiating elements 211 arranged in a matrix, with gaps formed between any two adjacent radiating elements 211. The four gaps combine to form a cross slot. The four radiating elements 211 are divided diagonally into a first dipole and a second dipole, each arranged in a central, perpendicular cross pattern. Specifically, a first feed strip is provided between the two radiating elements 211 of the first dipole. One end of the first feed strip is connected to one of the radiating elements 211, and the other end has a first feed hole 212 formed therein. A second feed strip is provided between the two radiating elements 211 of the second dipole. One end of the second feed strip is connected to one of the radiating elements 211, and the other end has a second feed hole 213 formed therein. The first and second feed strips are vertically intersecting and offset from each other. Two insertion holes 214 are provided on the printed circuit board 21 at positions away from the first feeding hole 212 and the second feeding hole 213 .

[0029] In this embodiment, two support bars 23 are vertically and parallelly arranged on the floor 22. That is, the lower ends of the support bars 23 are connected to the floor 22. The upper ends of the two support bars 23 are respectively connected to the two sockets 214 of the printed circuit board 21 (perhaps by welding, etc.). The support bars 23 are made of metal. The two support bars 23 are respectively connected to the first dipole and the second dipole, and are connected to the floor 22 to form a communication, thereby achieving a short circuit effect and supporting the printed circuit board 21.

[0030] In this embodiment, two through-holes are provided on the floor 22 for the passage of two coaxial cables 24 . The two coaxial cables 24 are respectively passed through the two through-holes and connected to the first feeding hole 212 and the second feeding hole 213 . The inner conductor of the coaxial cable 24 is connected to the first dipole and the second dipole, and the outer conductor of the coaxial cable 24 is connected to the printed circuit board 21 . Thus, the coaxial cable 24 now has a feeding function and serves to support the printed circuit board 21 .

[0031] In this embodiment, each radiating unit 211 is composed of a radiating ring and a radiating block, and the radiating ring is arranged adjacent to the outer periphery of the radiating block. The above-mentioned cross-dipole feed 2 has the characteristics of simple structure, stable radiation and wide bandwidth.

[0032] In this embodiment, a wire-passing hole is provided in the center of the reflector 3 for the passage of a coaxial cable 24 and other wires (not shown). The floor 22 is fixed to the reflector 3. Furthermore, both ends of the reflector 3 are bent upward to form reflective rails 31, forming a "U"-shaped structure with the two reflective rails 31. This "U"-shaped structure effectively reflects electromagnetic waves, improving the directivity of antenna radiation. The reflector 3 and the two reflective rails 31 can be produced using a stamping process, which is more cost-effective.

[0033] By combining the director assembly, the cross-dipole feed 2 and the reflector 3, a dual-polarization wide-bandwidth high-gain quasi-Yagi antenna capable of covering the 3.3-3.8 GHz frequency band is realized.

[0034] In order to facilitate the understanding of the above-mentioned Yagi antenna, further explanation is given below with reference to specific drawings.

[0035] See also Figure 7 The antenna's S-parameter plot shows that for +45° polarization, S11 is less than -15dB in the 3.3GHz-3.8GHz frequency range, and for -45° polarization, S22 is less than -20dB in the 3.3GHz-3.8GHz frequency range. Both polarizations effectively cover 14% of the 5G-C frequency band (3.3GHz-3.8GHz). Isolation between the two polarizations is greater than 18dB in the 3.3GHz-3.8GHz frequency range.

[0036] See also Figure 8 From the antenna gain diagram shown, it can be concluded that the gain of +45° polarization is 14.2dBi-15.3dBi in the frequency range of 3.3GHz-3.8GHz, and the gain of -45° polarization varies from 14.2dBi-15.1dBi within the effective frequency band.

[0037] See also Figure 9 The directional pattern of the +45° polarization is shown, and Figure 10 From the -45° polarization pattern shown, it can be concluded that the antenna has good directional radiation characteristics.

[0038] See also Figure 11 From the before-after ratio diagram of the two polarizations shown, it can be concluded that the antenna has high gain characteristics.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any person skilled in the art who, without departing from the scope of the technical solution of the present invention, utilizes the technical content disclosed above to make more possible changes and modifications to the technical solution of the present invention, or modifications are all equivalent embodiments of the present invention. Therefore, any equivalent and equivalent changes made in accordance with the ideas of the present invention without departing from the content of the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual-polarized wide-bandwidth high-gain quasi-Yagi antenna for tunnel communication scenarios, comprising a guide assembly, a cross-dipole feed (2) and a reflector (3), characterized in that: The guiding assembly comprises three equally spaced directors (11), each of the directors (11) comprising a guiding main rod (111) and a plurality of guiding units (112) arranged on the guiding main rod (111), and each guiding unit (112) comprising four antenna arms; the cross-dipole feed source (2) comprises a printed substrate (21), a floor (22), a support bar (23) and two coaxial cables (24); a radiation assembly is printed on the surface of the printed substrate (21), and the upper and lower ends of the support bar (23) are respectively connected to the printed substrate (21) and the floor (22); the coaxial cable (24) is connected to the printed substrate (21) after passing through a pre-opened hole in the floor (22); the floor (22) is fixed on the reflector (3); The guide units (112) on the same guider (11) are arranged at equal intervals in the length direction of the guide main rod (111); The radiation component comprises four radiation units (211) arranged in a matrix, the four radiation units (211) being divided into a first dipole and a second dipole in a central vertical cross shape according to a diagonal relationship, and all radiation components are arranged above the printed substrate (21).

2. The dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios according to claim 1, characterized in that: The four antenna arms are respectively arranged with the main pole (111) as the center and extending in the azimuths of 45°, 135°, 225°, and 315° in the clockwise direction, wherein the two antenna arms located at the azimuths of 45° and 135° form a group, and the two antenna arms located at the azimuths of 225° and 315° form a group.

3. The dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios according to claim 1, characterized in that: Each of the antenna arms has a sheet-like structure.

4. The dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios according to claim 1, characterized in that: The two coaxial cables (24) are respectively connected to the feeding strips of the first dipole and the second dipole.

5. The dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios according to claim 1, characterized in that: Each radiation unit (211) consists of a radiation ring and a radiation block, wherein the radiation ring is arranged adjacent to the periphery of the radiation block.

6. The dual-polarization, wide-bandwidth, high-gain quasi-Yagi antenna for tunnel communication scenarios according to claim 1, characterized in that: Both ends of the reflective plate (3) are bent upward to form reflective fences (31); this structure can effectively reflect electromagnetic waves and improve the directivity of antenna radiation.

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