Single-/Dual-Band Linear Polarization Converter With Independently Controllable Passband and High Selectivity

A reflective polarization converter (PC) with independently controllable passband is proposed using two dipole antennas and a bandpass filter. The vertically allocated dipole antennas and the horizontally placed bandpass filter are combined with each other to form an antenna-filter-antenna structure, which can realize polarization conversion and filtering performance simultaneously. Single- and dual-band PCs with controllable filtering responses and high selectivity are designed, where single- and dual-band filtering characteristics can be achieved as long as the microstrip filter structure is changed. To validate the design concept, a dual-band PC is fabricated and measured, where the measurement and simulation results are in good agreement. The measured lower and upper band-edge roll-off rates of the dual-band PC are 234 dB/GHz and 95 dB/GHz, and 93 dB/GHz and 69 dB/GHz, respectively, featuring high selectivity. The proposed PC will have significant potential applications in wireless communication systems.