Research On 2D Planar Beam Scanning Array Antenna Technology

With the development of 5G communication,radar detection and automotive electronic technology in the microwave and millimeter wave band,the electronic scanning array antenna which can search,detect and track multiple targets quickly has been deeply researched and widely used.The two-dimensional planar beam scanning array antenna has attracted more and more attention due to its advantages of wide scanning range,low profile,easy processing,low cost and easy integration.Based on the application background of C-band detection radar and24 GHz automotive anti-collision radar,this paper studies and designs C-band plane reflection beam scanning array antenna and 24 GHz beam scanning grid array antenna.The main research contents of this paper are as follows:1.This article first briefly reviews the development status,application background and working mechanism of beam scanning antennas,then emphatically introduces two types of beam scannable two-dimensional planar array antennas with different application scenarios,and finally describes the research content and work arrangement of the paper.2.A C-band 2D planar beam scanning reflective antenna array applied to detection radar is designed.In this paper,a reflection array antenna unit is proposed,which is composed of a square metal ring and a square patch.At the same time,a varactor and an inductive metal cylinder are loaded between the ring and the patch,as well as between the ring and the metal ground respectively,besides,the amplitude and phase information of the unit are extracted based on the parallel-plate waveguide model.After optimization,when the antenna works within 6.6–7.05 GHz,the phase adjustment range of the unit is greater than 320°,and the reflection efficiency is higher than-0.375 dB.Then a 12×12 plane reflection array antenna is designed based on the optimized array unit,the plane reflection array antenna can achieve a beam scanning of±60°in two-dimensional space.The side lobe level of the bistatic RCS is less than-10 dB,and the reflection efficiency is higher than-3 dB within the beam scanning range of±55°.3.A 24 GHz beam scanning microstrip grid array antenna for automotive collision avoidance radar is proposed.For the first time,beam scanning is achieved by combining a 4×4 substrate integrated waveguide?SIW?Butler matrix with a microstrip grid array.According to the relevant theories in the design of SIW-microstrip transition structure,the distance between the feeding via of the grid array antenna and the short circuit end of the SIW is determined.Then the non-radiating edges at both ends of the grid array are removed and the array structure is optimized to improve the gain of the antenna and reduce the side lobe level when the scanning angle increases.According to the simulation results,the operating bandwidth of the antenna array is 22.52–26.1 GHz(|S_ij|<-10 dB,i=1–4,j=1–4),and the antenna can achieve a beam of±20°within its bandwidth Scanning,the maximum gain can reach 14.6 dBi,and the side lobe level is lower than-10.7 dB.When the antenna works at 24 GHz,the reflection coefficient of each input port and the isolation between the ports are less than-17.2 dB,and the cross-polarization ratio is greater than 16.93 dB.In addition,the antenna has a low profile and low cost,with a thickness of only 1.27 mm.