Low profile metallic self-polarizing Fabry-Perot cavity antenna

A novel Fabry-Perot cavity resonator is proposed here. It is excited by a simple linearly-polarized waveguide source and it radiates in circular polarization without the need for a special feed system. It consists of a classical FP resonator combined with a polarization twister element. Analytical results, full wave simulations, and measurements are in close agreement. A combined 3 dB gain bandwidth, 3dB axial ratio bandwidth, and -10 dB impedance bandwidth of 3% is measured with a maximum gain of 18 dBi. The size of the antenna is 4.0λ₀ × 4.0λ₀ × λ₀. It is an attractive solution for use in high power transmitters in small satellites where size is a major constraint.