CN216624582U

CN216624582U - Compact broadband grid array antenna

Info

Publication number: CN216624582U
Application number: CN202122570174.XU
Authority: CN
Inventors: 刘宇峰; 郝刚; 张骄; 韩国瑞; 陈新伟
Original assignee: Shanxi University
Current assignee: Shanxi University
Priority date: 2021-10-25
Filing date: 2021-10-25
Publication date: 2022-05-27
Anticipated expiration: 2031-10-25

Abstract

The utility model discloses a compact broadband grid array antenna, which comprises an upper dielectric substrate, an upper metal patch, a lower dielectric substrate, a lower metal patch, a metal ground plate and a coaxial probe, the upper metal patch is attached to the upper surface of the upper dielectric substrate and comprises an upper rectangular patch and an upper bending transmission line which is bent inwards, the lower metal patch and the metal ground plate are respectively attached to the upper surface and the lower surface of the lower dielectric substrate, the lower layer metal patch is provided with a concentric double-ring broadband AMC unit which comprises a large ring patch and a small ring patch, an air layer is arranged between the upper-layer dielectric substrate and the lower-layer dielectric substrate, and a coaxial probe is arranged between the edge of the upper-layer rectangular patch near the center and the lower-layer dielectric substrate in a penetrating manner. The utility model can solve the problem of insufficient bandwidth of the existing grid array antenna.

Description

Compact broadband grid array antenna

Technical Field

The utility model relates to the technical field of antennas in wireless communication, in particular to a compact broadband grid array antenna.

Background

A grid array antenna is a planar array antenna having a plurality of rectangular wire loops or microstrip wire loops. It was proposed by Kraus in 1964 as a frequency scanning antenna for the line waves, and then gradually developed into a standing wave antenna of a microstrip version. Typically, the radiating edge of the grid is about half a wavelength and the transmission line connecting the radiating edges is about one wavelength to ensure that the electric fields at the radiating edges are in phase to form a main radiation beam and to produce low cross-polarization in the direction of the transmission line perpendicular to the radiating edges.

The advantages of the grid array antenna are:

1. the gain of the antenna is high and is obviously higher than that of the patch array antenna with the same number of units, and the control of cross polarization can be realized by adjusting the width of the long edge of each unit.

2. The feeding technology is simple, and a coaxial probe is generally used for feeding in the center of the antenna.

3. The antenna has a lower profile and can be attached to the surface of a carrier to form a conformal antenna.

However, due to the narrow-band nature of microstrip lines, the bandwidth of a lattice array antenna is typically less than 10%, limiting its usefulness. With the rapid development of wireless systems and the increasing demand of various wireless applications, it is important to design a wide-band, high-gain antenna to cover a wider frequency range.

In recent years, scholars at home and abroad propose grid array antennas with improved bandwidth. For example, in 2014, Khan o, et al, in the paper "antenna band variable width microstrip grid array antenna array", proposed a structure of a multi-layer grid array, where a feed network is designed separately, which facilitates impedance matching between a port and an antenna input, and an impedance bandwidth reaches 10.7%, but a 3-dB gain bandwidth is only 5.1%; in 2019, Wai Yan Yong et al in the paper "Wideband Grid Array Antenna for 28GHz 5G Base Station" improved the shape of the Grid unit, loaded a diamond patch on the short side of the Grid, and adjusted the diamond width by using a taper distribution method, the impedance bandwidth was increased to 16.07%, but the peak gain only reached 14.8dBi (13 radiating units). Methods for increasing antenna bandwidth generally include: the thickness of the antenna is increased to reduce the Q value of the antenna so as to improve the bandwidth; smoothing the outline of the radiating patch to obtain a flat impedance frequency characteristic, and the like. However, these methods usually cause a large reduction in gain, and the bandwidth is not significantly increased, which is still lower than 20%; further, many of the improved antennas have complicated structures or too high profiles, which are not easy to manufacture and debug, and are difficult to be put into practical use. Therefore, poor bandwidth performance is a key factor limiting the wide application of grid array antennas.

SUMMERY OF THE UTILITY MODEL

To overcome the disadvantages and shortcomings of the prior art, a compact wideband grid array antenna is provided to solve the problem of insufficient bandwidth of the prior grid array antenna.

The utility model provides a compact broadband grid array antenna for realizing the aim of the utility model, which comprises an upper dielectric substrate, an upper metal patch, a lower dielectric substrate, a lower metal patch, a metal ground plate and a coaxial probe, the upper metal patch is attached to the upper surface of the upper dielectric substrate and comprises an upper rectangular patch and an upper bending transmission line which is bent inwards, the lower metal patch and the metal ground plate are respectively attached to the upper surface and the lower surface of the lower dielectric substrate, the lower layer metal patch is provided with a concentric double-ring broadband AMC unit which comprises a large ring patch and a small ring patch, an air layer is arranged between the upper-layer dielectric substrate and the lower-layer dielectric substrate, and a coaxial probe is arranged between the edge of the upper-layer rectangular patch near the center and the lower-layer dielectric substrate in a penetrating manner.

The utility model has the beneficial effects that:

compared with the prior art, the compact broadband grid array antenna provided by the utility model has the advantages that when the antenna works, the upper layer rectangular patch positioned in the upper layer horizontal direction serves as a radiating element to generate in-phase horizontal polarized waves, the upper layer bent transmission line connected with the upper layer rectangular patch is equivalent to a transmission line, and the 360-degree resonance phase delay is provided. The antenna produces a directional radiation beam with low cross-polarization in the lateral direction. The large ring patches and the small ring patches positioned on the lower layer are periodically arranged and used as AMC units to perform in-phase reflection on incident waves, and the gain of the antenna is improved.

Compared with the prior art, the utility model has the following advantages:

(1) the upper-layer bent transmission line of the grid array element is bent inwards, and the resonance length is increased while the surface current path is expanded, so that the bandwidth of the antenna is improved, and the radiation aperture is reduced;

(2) the AMC reflector replaces a traditional metal plate reflector, so that the profile height of the antenna is reduced, and the directivity of the antenna is improved;

(3) a concentric double-ring broadband AMC unit is adopted, and the equivalent circuit of the unit is in near-field coupling with the antenna, so that the bandwidth performance of the antenna is further improved;

(4) the antenna has simple structure, good reliability and convenient manufacture and debugging, and provides feasibility for the application of the grid array antenna in a wireless communication system.

Drawings

The following detailed description of embodiments of the utility model is provided in conjunction with the appended drawings, in which:

fig. 1 is a structural diagram of a grid array antenna according to the present invention;

fig. 2 is a side view of a grid array antenna according to the present invention;

FIG. 3 is a reflected phase curve of an AMC unit of a grid array antenna according to the present invention;

FIG. 4 is a graph of the S-parameter of a grid array antenna according to the present invention;

FIG. 5 is a gain curve of a grid array antenna according to the present invention;

FIG. 6 is an E-plane radiation pattern of the grid array antenna of the present invention at 5.8 GHz;

FIG. 7 is an H-plane radiation pattern of a grid array antenna of the present invention at 5.8 GHz;

in the drawings: 1-upper dielectric substrate, 2-air layer, 3-lower dielectric substrate, 4-metal grounding plate, 5-coaxial probe, 6-upper rectangular patch, 7-upper bending transmission line, 8-large circular patch and 9-small circular patch.

Detailed Description

As shown in fig. 1 and 2, the compact broadband grid array antenna provided by the utility model comprises an upper dielectric substrate 1, an upper metal patch, a lower dielectric substrate 3, a lower metal patch, a metal ground plate 4 and a coaxial probe 5, wherein the upper metal patch is attached to the upper surface of the upper dielectric substrate 1, the upper metal patch comprises an upper rectangular patch 6 and an upper bending transmission line 7, the bending distance of the upper bending transmission line 7 is 2.8mm, the lower metal patch and the metal ground plate 4 are respectively attached to the upper surface and the lower surface of the lower dielectric substrate 3, a concentric double-ring broadband AMC unit is arranged on the lower metal patch, the concentric double-ring broadband AMC unit comprises a large ring patch 8 and a small ring patch 9, the outer diameters of the large ring patch 8 and the small ring patch 9 are respectively 4.0mm and 2.5mm, the width of the ring is 0.5mm, the arrangement mode of the large circular ring patches 8 and the small circular ring patches 9 is 14 multiplied by 14, an air layer 2 is arranged between the upper layer dielectric substrate 1 and the lower layer dielectric substrate 3, and a coaxial probe 5 is arranged between the edge of the upper layer rectangular patch 6 near the center and the lower layer dielectric substrate 3 in a penetrating mode.

Through numerical calculation and antenna test, the impedance bandwidth of the antenna can be extended from 4.65GHz to 6.07GHz and reaches 24.5%, which far exceeds the bandwidth (lower than 10%) of the prior grid array antenna. The 3dB gain reduction bandwidth is 5.21-6.49GHz and reaches 22.1%. With a 21.9% reduction in the grid element area, the maximum gain at 5.8GHz is obtained, 16.6dBi, which is far in excess of the gain of the existing grid array antenna of the same number of elements (about 14 dBi).

As shown in fig. 3, the reflection phase curve of AMC is very gentle at low frequencies, and as the frequency increases, the electrical size of the cell increases rapidly, the curve trend becomes steep, and the reflection phase reaches a maximum at 7.25 GHz. The reflection phase at +90 deg. to-90 deg. corresponds to a frequency range of the AMC operating bandwidth, i.e. extending from 3.38GHz to 7.17 GHz, and the reflection phase at 0 deg. corresponds to a resonance frequency of 6.28GHz, with a relative bandwidth of up to 60%.

As shown in fig. 4, the reflection coefficient curve of the antenna has 3 resonance points, and the resonance frequencies are 4.70 GHz, 5.10GHz, and 5.71GHz, respectively. The matching effect at 5.71GHz is best, and the amplitude is lower than-40 dB. Corresponding to | S₁₁The bandwidth of | < -10dB is 4.65-6.07GHz, which reaches 24.5%. The improvement in the form of the grid elements in combination with the use of a wideband AMC reflector increases the impedance bandwidth of the antenna.

As shown in fig. 5, the gain curve shows that the antenna has the highest gain at the center frequency and decays away from the center. There is a maximum gain of 16.6dBi at 5.8GHz and a 3-dB gain reduction bandwidth of 5.21-6.49 GHz. In the frequency band range of 5.5GHz to 6.30GHz, the gain curve is relatively flat, and the gain change value is within 1 dBi.

As shown in fig. 6, the main beam of the E-plane pattern is shifted 9 ° to the left because the feed location is offset from the geometric center of the antenna, and thus the phase center of the structure is not the geometric center. The first side lobe level is-25 dB and the half power beamwidth is 31.9 °. The cross-polarization level is low and cannot be shown in the directional diagram.

As shown in fig. 7, the solid black line represents a beam generated by H-plane main polarization, and the dashed black line represents a beam generated by H-plane cross polarization. The main beam points in the direction of the boresight and the directional pattern is completely symmetrical about the main lobe. The first side lobe level is-15 dB and the half power beamwidth is 21.9 °. The cross polarization level is low, and the difference of the main cross polarization is more than 25 dB.

The above embodiments are not limited to the technical solutions of the embodiments themselves, and the embodiments may be combined with each other into a new embodiment. The above embodiments are only for illustrating the technical solutions of the present invention and are not limited thereto, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the technical solutions of the present invention.

Claims

1. A compact broadband grid array antenna characterized by: including upper dielectric substrate, upper metal paster, lower floor's dielectric substrate, lower floor's metal paster, metal ground plate and coaxial probe, upper metal paster pastes the upper surface of adorning in upper dielectric substrate, upper metal paster includes upper rectangle paster and the upper transmission line of buckling inwards, lower floor's metal paster and metal ground plate paste respectively adorn in the upper surface and the lower surface of lower floor's dielectric substrate, be provided with concentric double-ring broadband AMC unit on the metal paster of lower floor, concentric double-ring broadband AMC unit includes big ring paster, small circle ring paster, be provided with the air bed in the middle of upper dielectric substrate and the lower floor's dielectric substrate, link up between the edge that is located near the upper rectangle paster in center and the lower floor's dielectric substrate and be provided with coaxial probe.