Millimeter wave circularly polarized substrate integrated waveguide antenna

A millimeter wave circularly polarized substrate integrated waveguide antenna is proposed. The proposed antenna is constructed by a quasi H-type radiating slot on the broad wall of a substrate integrated waveguide and the microstrip stepwise input and output impedance matching networks. Analysis and design approaches are given in the paper. With the help of the electromagnetic simulator, a circularly polarized antenna operated at Ka-band is designed. The designed results show that the centre frequency of the antenna is 30 GHz, the circularly polarized axial ratio at 30 GHz in the main beam direction is 0.36 dB, the 3 dB circularly polarized axial ratio bandwidth is 1.35 GHz, the -10 dB return loss bandwidth is 350 MHz.