Design of a Circular Polarized Filter-antenna

This article presents a design of a circular patch filter-antenna featuring left-hand circular polarization, high directionality, and a gain exceeding 6dB. It aims to simulate excellent performance metrics: S
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< 10dB, axial ratio AR < 3dB at the center frequency of 5.8GHz. Achieving this filter-antenna involves integrating a third-order Chebyshev bandpass filter with a circular patch antenna, enabling left-hand circular polarization. The antenna design incorporates two slots in the circular patch to induce circular polarization, while the bandpass filter utilizes a square open-loop resonator (SOLR) for its design. The result is a filter-antenna configuration that delivers circular polarization across a wide angular range.