Substrate integrated waveguide circularly polarized antenna

A novel circularly polarized array antenna based on substrate integrated waveguide (SIW) is presented in this paper. The array element, a circularly polarized radiator, consists of two 45° inclined radiating slots. Its feeding port is very simple. The axial ratio in the main beam direction is less than 3dB. And the gain of one unit cell is around 4dBi. To increase the gain, antenna array is used. The investigation on Four-Element array antenna is studied, which can achieve a gain of 6.8dBi.