Circular polarization microstrip antenna at W band

A circular polarization array antenna at W band is designed by analyzing and comparing different feeding forms, using constant amplitude and in-phase feeding and waveguide-microstrip transition. According to the theoretical analysis and simulation results, the loss of W band antenna can be reduced, good axial ratio and suitable arrangement of feeding network can be realized by choosing proper dielectric, using waveguide-microstrip transition and constant amplitude and in-phase feeding of each unit radiation patch, which is ideal for the realization of circular polarization array antenna at W band. The bandwidth of the 8×8 array antenna are 4.3% when S(1, 1)<-15 dB. The beamwidth of the antenna is 11° when axial ratio is below 3 dB. And the maximum achievable gain of this antenna is 20.6 dB. Test and simulation results are in good agreement.