Circularly Polarized Fabry–Perot Antenna Using a Hybrid Leaky-Wave Mode

This paper presents the spectral Green's function (GF) to analyze Fabry-Perot antennas to generate circular polarization (CP). The structure consists of a single cavity created between a partially reflective surface and a high impedance surface, fed by a low directive, linearly polarized source. Elements in the antenna are characterized by tensor impedances. It allows conceiving a circularly polarized antenna supporting a single hybrid leaky-wave mode. Residue analysis is used to demonstrate that a single hybrid leaky-wave mode is sufficient to generate CP. The tool is validated by an antenna design matched over a relative bandwidth of 28.5% with an axial ratio lower than 3 dB.