A Low-Cost High-Performance Dual-Band Diaphragm Circular Polarizer

In this paper, a novel dual-band dielectric-diaphragm circular polarizer with simple structure and good performance is presented, which can effectively improve the return loss and bandwidth characteristics through innovation in its structure. Simulation and experiment results show that the circular polarizer can decompose an incident linearly polarized wave into two components whose phase difference ranges from 85° to 95° and amplitudes are equal in dual frequency bands of 19.6-21.2GHz and 29.4-31.0GHz. Simulated return loss is better than -30dB, while the experiment one is below -10dB. By cascading the polarizer with a corrugated horn antenna, simulation results of axial ratio are less than 2dB at the center frequencies of the dual band, i.e., 20.4GHz and 30.2GHz.