Research On Ku Band Satellite Communication Array Antenna

Satellite communication has the advantages of wide coverage,high communication capacity,excellent transmission quality and little impact on the geographical environment.These advantages have made satellite communication more and more attention,and it has become the key research object of the majority of scientific researchers.Therefore,in accordance with the needs of satellite communications,this article studies the Ku-band satellite communications dual-circular polarization transceiver antenna.This thesis divides the satellite communication antenna system into three parts: antenna,feeder network and filter.After reading a lot of literature to understand the basic principles of each part of the structure,and then design a miniaturized broadband dual circularly polarized antenna suitable for Ku-band satellite communications based on project indicators.The main work of the thesis includes the following aspects:First of all,the thesis conducts research on satellite communication antennas,and designs a dual circularly polarized antenna that works in the Ku band based on the microstrip antenna.The antenna uses a parasitic patch structure to expand the impedance bandwidth,and the parasitic patch improves the circular polarization axis ratio by cutting corners.Solve the problem of integration of parasitic patch and radiation patch through injection molding process and welding.The simulation results show that the antenna impedance bandwidth of the receiving frequency band is greater than 16%,and the 3dB axial ratio bandwidth reaches18%;the antenna impedance bandwidth of the transmitting frequency band is greater than17%,and the 3dB axial ratio bandwidth reaches 14%,achieving the goal of broadbandization.Secondly,according to the realization of dual circular polarization of the antenna,the branch line type directional coupler is studied,the port parameter matrix of the directional coupler is deduced,and the receiving and transmitting double branch line type directional coupler suitable for the antenna structure is designed.The multi-layer board process is used to integrate the directional coupler and the antenna,which reduces the overall volume of the antenna and the feed network.The amplitude difference of the output ports of the two directional couplers in the working frequency band is less than 0.5dB,and the phase difference is 90°±3°.After cascading the designed antenna and the directional coupler,the overall size is less than 0.25?×0.25?,achieving the goal of miniaturization.Thirdly,in response to the requirement of signal suppression for the transmitting and receiving antennas,a waveguide cavity bandpass filter is designed.The filter is connected to the antenna through the KK connector.The commonly used filter functions are introduced.The insertion loss of the receiving filter designed on the basis of the Chebyshev filter function is less than 0.5dB,the out-of-band rejection is more than 50 dB,the insertion loss of the transmitting filter is less than 1.2dB,and the out-of-band rejection is more than 80 dB.Achieved the goal of high isolation.Finally,a physical processing test is carried out.The test results of each component are basically consistent with the simulation results,which proves the feasibility of the design scheme proposed in this thesis,and provides a certain reference value for the antenna design of the satellite communication system.