Broadband omnidirectional antenna

Abstract

The invention provides a broadband omnidirectional antenna which is characterized in that the antenna is composed of two U-shaped modules, a bisection power divider and a coaxial feeder line; each U-shaped module is composed of a U-shaped reflecting plate, a radiation patch and a probe and can form a broadband weak directional wave beam, the two U-shaped modules are arranged back to back at a certain interval, the interval distance is slightly larger than the outer diameter of a coaxial feeder line, and the U-shaped modules are used for collecting the coaxial feeder line and enabling the coaxial feeder line to pass through smoothly. The two U-shaped modules are connected with a bisection power divider through respective coaxial probes and are subjected to in-phase synthesis to obtain a broadband omnidirectional wave beam of which the frequency bandwidth is greater than 85.7%; and a plurality of broadband omnidirectional antennas are linearly arranged, so that a broadband high-gain omnidirectional array is easy to form.

Description

Technical Field

[0001] The present invention relates to an antenna broadband technology, and particularly to a broadband omnidirectional antenna that is easy to array. Background Art

[0002] The beam of an omnidirectional antenna is wide and the coverage range is large. Usually, multiple radiation units are arranged in a linear array to improve the gain. Common omnidirectional antennas in the form of monopoles with a ground plane, loaded dipole oscillators, etc. are easy to achieve broadband, but after arranging multiple radiation units in an array, the influence of the feeder on the antenna performance usually cannot be eliminated, resulting in difficult arraying in most cases, only a single radiation unit working and low gain; an omnidirectional antenna obtained by forming a circular array with multiple directional units and feeding them equally in amplitude and in phase, although it is convenient to increase the gain by arraying, common broadband directional units usually have large sizes and limited bandwidths. These factors make it difficult to obtain a practical high-gain broadband omnidirectional antenna.

[0003] "Practical Antenna Engineering Technology" edited by Ju Xinde et al. mentions a dual-band broadband patch antenna formed by feeding a rectangular patch with a coplanar probe on a U-shaped ground plane, achieving dual-band directional beams with relative bandwidths of 50% and 30%. (Ju Xinde et al. Practical Antenna Engineering Technology [M]. Xi'an University of Electronic Science and Technology Press, 2015: 479-480) Summary of the Invention

[0004] The present invention provides a broadband omnidirectional antenna, which is composed of two U-shaped modules, a two-way power divider, and a coaxial feeder; the U-shaped module is composed of a U-shaped reflector, a radiation patch, and a probe, and can form a broadband weak directional beam. The two U-shaped modules are installed back to back with a certain distance between them, and the distance is slightly larger than the outer diameter of the coaxial feeder, used to accommodate the coaxial feeder and allow the coaxial feeder to pass through smoothly; the two U-shaped modules are connected to a two-way power divider through their respective coaxial probes and synthesized in phase to obtain a broadband omnidirectional beam with a frequency bandwidth greater than 85.7%; multiple broadband omnidirectional antennas are arranged in a straight line, which is easy to form a broadband high-gain omnidirectional array.

[0005] The beneficial technical effects of the present invention are: the broadband omnidirectional antenna obtains a frequency bandwidth greater than 85.7%, and the performance such as standing wave, gain, and radiation pattern within the band is good; the diameter of the antenna is reduced by the chamfering measure of the side plate of the U-shaped reflector; the internal gap of the antenna reserves the wiring space for the coaxial feeder, providing favorable conditions for high-gain arraying. Brief Description of the Drawings

[0006] Figure 1 Schematic diagram of the external shape of the present invention; Figure 2 Three views of the present invention; Figure 3 Voltage standing wave ratio of the antenna Figure 4 and the azimuth plane pattern of the antenna; Figure 5 and the elevation plane pattern of the antenna. Embodiment

[0007] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0008] As Figure 1 , Figure 2 shown, the present invention provides a broadband omnidirectional antenna, which is composed of two identical U-shaped modules, a two-way power divider, and a coaxial feeder; the U-shaped module is composed of a U-shaped reflector, a radiation patch, and a probe, and can form a broadband weak directional beam. The two U-shaped modules are installed back-to-back with a certain distance between them, and the distance is slightly larger than the outer diameter of the coaxial feeder, used to house the coaxial feeder and enable the coaxial feeder to pass through smoothly; the two U-shaped modules are connected to a two-way power divider through their respective coaxial probes and synthesized in phase to obtain a broadband omnidirectional beam; multiple broadband omnidirectional antennas are arranged in a straight line, which is easy to form a broadband high-gain omnidirectional array.

[0009] The U-shaped reflector is composed of a bottom plate and two side plates. The two side plates are perpendicular to the bottom plate, and the outer dimensions of the two side plates are the same. The two corners of the side plates that are not connected to the bottom plate are chamfered to reduce the diameter of the overall shape of the antenna. The radiation patch is located inside the U-shaped reflector and parallel to the bottom plate. One end of the probe is connected to the radiation patch, and the other end passes through one side plate of the U-shaped reflector and is soldered to the branch end of the two-way power divider. The two-way power divider is a microstrip T-shaped power divider, and the microstrip line uses a tapered line. The tapered line and the ground layer are respectively laid on the upper and lower layers of the double-sided high-frequency printed circuit board. The ground layer of the power divider printed circuit board is closely attached to the side plate of the U-shaped reflector. The coaxial feeder is located on one side of the ground layer of the power divider printed circuit board. The outer conductor of the coaxial feeder is soldered to the ground layer of the power divider printed circuit board, and the inner conductor of the coaxial feeder passes through the power divider printed circuit board and is soldered to the tapered line.

[0010] A specific embodiment: The operating frequency is 1.0 GHz to 2.5 GHz, and the frequency bandwidth is 85.7%. The size of the bottom plate of the U-shaped reflector is 57 mm in length and 60 mm in width, the size of the side plate is 30 mm in height, 60 mm in width, and the chamfer radius of the two corners is 15 mm. The size of the radiation patch is 24 mm in length and 60 mm in width, and it is 15 mm away from the bottom plate of the U-shaped reflector. The microstrip power divider is laid on a printed circuit board with a dielectric constant of 2.7 and a thickness of 1 mm, and the width of the tapered line varies from 2 mm to 1 mm. The back gap between the two U-shaped modules is 5 mm, and the coaxial feeder uses a No. 3 semi-flexible coaxial cable with an outer diameter of 3.6 mm. The maximum diameter of the antenna shape is 77 mm.

[0011] As Figure 3The voltage standing wave ratio results of the antenna are shown. The abscissa represents the operating frequency, and the ordinate represents the voltage standing wave ratio. Within the range of 1.0 GHz to 2.5 GHz, the voltage standing wave ratio of the antenna is not greater than 1.8:1.

[0012] As Figure 4 , Figure 5 shown are the polar diagrams of the azimuth plane and elevation plane of the antenna respectively. The radial direction represents the gain, with the unit of dBi, and the polar angle represents the azimuth angle or elevation angle, with the unit of °. At 1.0 GHz, 1.5 GHz, 2.0 GHz, and 2.5 GHz, the maximum gains of the antenna at each frequency point are 2.5 dBi, 2.1 dBi, 2.1 dBi, and 2 dBi respectively. The beam non-circularity of the azimuth plane is 1.4 dB, 1.2 dB, 1.6 dB, and 1.8 dB respectively, and the beam widths of the elevation plane are 91°, 96°, 105°, and 112° respectively.

Claims

1. A broadband omnidirectional antenna, characterized in that, It consists of two identical U-shaped modules (1), a two-way power divider (2), and a coaxial feeder (3); the U-shaped module (1) is composed of a U-shaped reflector (4), a radiation patch (5), and a probe (6). The two U-shaped modules are installed back-to-back with a certain distance between them, and the distance is slightly larger than the outer diameter of the coaxial feeder to accommodate the coaxial feeder and allow it to pass through smoothly; the two U-shaped modules are connected to the shunt ports of a two-way power divider through their respective coaxial probes.

2. The antenna according to claim 1, characterized in that, The two side plates of the U-shaped ground plate are perpendicular to the bottom plate, and the outer dimensions of the two side plates are the same. Chamfers are made at the two corners of each side plate that are not connected to the bottom plate, and the chamfer radius is 1 / 2 of the height of the side plate.

3. The antenna according to claim 1, characterized in that, The radiation patch is located inside the U-shaped reflector and parallel to the bottom plate. One end of the probe is connected to the radiation patch, and the other end passes through one side plate of the U-shaped reflector and is soldered to the shunt end of the two-way power divider.

4. The antenna according to claim 1, characterized in that, The two-way power divider is a T-shaped power divider laid on a microstrip board, and the two shunt microstrip lines use tapered microstrip lines to achieve impedance matching.

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