Dual Circularly Polarized Antena With Bandpass Filtering Response

A novel dual circularly polarized filtering antenna by seamlessly integrating a substrate integrated waveguide dual-mode filter with a dual-port patch antenna is proposed in this paper. Owing to the characteristics of the dual-mode cavity, different circular polarization (RHCP and LHCP) could be achieved by switching between the different feeding ports of antenna. This developed antenna exhibits a simulated impendence bandwidth of 4% and an axial ratio bandwidth of 2% at 5 GHz. In addition, a bandpass filtering response is achieved resulting from a TE
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dual mode operation. The antenna prototype is fabricated and tested. The measured results are in good agreement with simulation.