Research On Millimeter-wave Gap Waveguide Filter And Multi-beam Antenna Array

In the current years,the fifth generation mobile communication network(5G)has entered people’s life in an all-round way.It can well meet people’s needs for high-speed,broadband,high-capacity information transmission and exchange.The vigorous development of 5G technology also encourages the iteration and upgrading of related industrial technologies,especially the device system of RF(Radio Frequency)frontend,including the filter and multi-beam antenna array of the important passive devices in the RF system.Based on this research background,the millimeter-wave filter,crossover structure,and millimeter-wave multibeam antenna array are selected as the research objects in this thesis based on the gap waveguide technology.The main research work of this thesis includes:1.A millimeter-wave bandpass filter with high selectivity based on the gap waveguide technology is proposed.By adding multiple centralposts in the gap waveguide resonator,multiple resonant modes can be introduced.By using the mutual coupling between the dual-mode,a transmission zero with flexible position can be created.This is a combination design of frequency dependent coupling method and dualmode resonance method,which achieves the predetermined goal of miniaturization,and has the function of flexibly controlling the transmission zero position and bandwidth.The 17-dB impedance matching range of the bandpass filter is from 58.61GHz to 63.36 GHz,and the inband insertion-loss is 0.6 dB±0.2 dB.The prototype of the bandpass filter with high selectivity is fabricated and tested.2.A wideband crossover structure with low insertion-loss based on the ridge gap waveguide technology is proposed.The crossover structure can achieve good transmission performance by crossing two ridge waveguide transmission lines and widening the central-overlapping part.Two ridge waveguide transmission lines are in the same plane,and the 10dB impedance matching bandwidth of the crossover structure is from 42 GHz to 51 GHz,which can be flexibly used as a component in Butler matrix and other structures.By adding multi-stage impedance matching structure to this crossover structure,the prototype is processed and terminated with WR-22 waveguide port for testing.3.A multi-beam antenna array fed by 4×4 Butler matrix based on the groove gap waveguide technology is proposed.Based on the gap waveguide technology,each structure,including coupler,crossover and phase shifter of components of Butler matrix feed structure,and 1×4 antenna array has been designed.Then we combine the 1 ×4 antenna array with the 4×4 Butler matrix feed structure to obtain a multi-beam phased array antenna with four deflection beams.The beam deflection angles are±6° and ±19°,respectively.The maximum gain is 19.05 dBi and the maximum radiation efficiency is 86.8%,respectively.The physical prototype of the multi-beam antenna array was processed and measured.