Millimeter Wave Slot Array Antenna Based On Micro-Waveguide

The W band covers 75 GHz to 110 GHz and has abundant spectrum resources.Among them,94 GHz is an atmospheric window,and the attenuation of radio wave propagation is small,which is an ideal choice for radar applications.This paper focuses on the requirements for high gain,low profile,light weight,high isolation,and precise beamforming proposed by the antenna for airborne SAR applications.The design is completed by choosing a high-precision processing technology and a reasonable antenna element.1)A W-band two-dimensional low side-lobe micro-waveguide slot array antenna is researched and designed.Firstly,in view of the design contradiction between the array antenna beamwidth and antenna gain under area constraints,loading a stepped radiating cavity on the micro-waveguide radiating slot is proposed.Through reasonable design,the linear array gain can be increased without changing the H-plane beamwidth.Secondly,the equal power divider is used to form an unequal feeding network,and the E-plane low side-lobe beamforming is realized.Finally,based on the MEMS(MEMS: Micro Electromechanical System)bulk silicon process,the 20?8 elements two-dimensional low side-lobe micro-waveguide slot array antenna is processed and measured.The measured results show that the operating bandwidth is 92 GHz to 96 GHz.The effective gain in working band is 27.5 dBi with the antenna radiation efficiency is greater than 85%.The side-lobe levels of E-plane and H-palne are less than-19 dB,and the 3 dB beamwidths of them are 3.4° and 12.5°.The measured isolation in working band is greater than 60 dB.2)A W-band one-dimensional scanning four-channel phased array antenna based on micro-ridge waveguide is researched and designed.Firstly,the problem of difficult matching of micro-ridge waveguide slot array antenna is solved by introducing a parasitic slot.Then,the transition structure from standard waveguide to non-standard waveguide to micro-ridge waveguide is proposed,and the radiation pattern asymmetry of the micro-ridge waveguide linear array can be eliminated by staggered layout topology.Finally,based on the MEMS bulk silicon process,the four-channel one-dimensional scanning phased array antenna is processed and measured.The measured results show that the operating bandwidth is greater than 2 GHz.The effective gain in the working band of the single-channel antenna is 16.6 dBi.The measured scanning range of the phased array attains ± 30°.