Self-Generation of Circular Polarization Using Compact Fabry–Perot Cavity Antennas

A new configuration of a compact self-polarizing Fabry-Perot (FP) cavity antenna is presented. It is excited in single-linear polarization at 45^° and radiates in circular polarization. It consists of a polarizing FSS (used to ensure the polarization conversion) and a corrugated ground plane (designed to guarantee the resonance conditions for both incident orthogonal linear polarizations). A compact shielded FP antenna with an aperture of 1.62 λ₀ is optimized and fabricated in S -band to validate the concept at 2.5 GHz. A 3-dB axial-ratio bandwidth of about 1.9% is achieved with an antenna height of only 0.8 λ₀. The experimental results are in good agreement with the simulations. This antenna configuration is attractive for narrowband applications, like the space ones in C- or S-bands.