Single-Layer Circularly Polarized SIW Horn Antenna Based on Horn Phase Center

A single-layer circularly polarized (CP) substrate integrated waveguide (SIW) horn antenna is proposed. The proposed antenna is the combination of a classic SIW horn antenna and a printed dipole on the same substrate. The distance between the phase centers of the classic SIW horn antenna and the printed dipole contributes to the phase difference between the two orthogonal polarizations. Unlike the traditional antenna array with identical elements, the model in this work is essentially an array consisting of two different elements. The CP generation mechanism of the proposed antenna is discussed from the array perspective and a design guideline is laid down. The CP principle is verified by the simulated and measured results of the proposed antenna. The measured results show that the proposed CP SIW antenna has a 10-dB impedance bandwidth of 8.1% ranging from 10.6 GHz to 11.5 GHz, and its 3-dB AR bandwidth is 4.8% covering 10.73 GHz to 11.26 GHz. The radiation pattern of the proposed antenna is end-fire with a beam parallel with its plane.