Research On Phase Characteristics Of Gan Waveguide And Coupler And Millimeter-wave Antenna Array

The requirement for advanced wireless communication accelerates the improvement of communication technology all the time.The current low-frequency spectrum resources have been unable to satisfy the growing amount of mobile communication transmission data.A new generation of wireless communication system will develop to high-frequency bands,including submillimeter-wave and millimeter-wave bands.In the high-frequency bands,the traditional guiding structures are not suitable.However,the gap waveguide is very suitable for the design of high-frequency RF devices because of its low transmission losses,large power handling capability,low difficulties in processing and assembling,easy integration and so on.Based on the research background and status of gap waveguide,this paper mainly studies the theory and applications of gap waveguide.The work of this thesis mainly includes the following aspects.(1)A fast approximation method for the phase constant and electrical length of ridge gap waveguide(RGW)is proposed.By comparing the electrical length variations of a ridge gap waveguide,a ridge waveguide and an ideal microstrip transmission line,a fast approximation method is proposed to obtain the phase constant and electrical length of ridge gap waveguide.This convenient approximation method is confirmed by making a contrast between the simulated dispersion diagram and the approximate calculation results.This fast approximation method is very suitable for the early design of RGW-based RF devices.(2)A dual-band unequal coupler based on gap waveguide is proposed.By adopting the ridge gap waveguide rather than the microstrip line,the proposed coupler can work in millimeter-wave band with the characteristics of dual-band operation and unequal power division.In this paper,two examples working at 30 GHz and 60 GHz bands are proposed,and the former one is manufactured.The tested data presents that the resonant frequencies of the coupler are 33.6 GHz and 35.3 GHz respectively,and the power-dividing ratio of 2 dB is achieved.(3)A wideband antenna array based on gap waveguide is proposed.Each component of the antenna array is designed separately,including the symmetrical electromagnetic bandgap unit and the double-ridge zero-gap waveguide,the coaxial-to-ridge waveguide transition structure,the antenna array feeding network and the antenna array unit.The above components are integrated in one structure,and the novel antenna array realizes the characteristics of wideband operation,terminal opening radiation,compact structure and easy processing and assembling.The measured operating bandwidth of the antenna array is 24.1-39.7 GHz and the gain within the passband is more than 11.2 dB.