A ring probe fed metallic cavity antenna for circular polarization

A ring probe fed metallic cavity antenna for circular polarization is proposed in this paper. The aim is to increase the size and improve the bandwidth of satellite antennas working in the Ku-band and other higher-frequency bands through low cost and easy fabrication. A brass C-band antenna prototype is designed and simulated for concept verification. The overall dimensions of the antenna are 0.73λ₀ × 0.73λ₀ × 0.90λ₀ at the working frequency. The resonant mode and circular polarization of the proposed cavity antenna is excited by a coaxial feeding ring probe. The simulated impedance bandwidth for |S₁₁| ≤ - 10 dB and 3-dB axial-ratio bandwidth are 1.01 GHz (7.01 GHz to 8.02 GHz) and 0.82 GHz (7.11 GHz to 7.93 GHz) respectively. The simulated 3-dB axial-ratio beamwidths at the central frequency are 160° and 156° in the x-z and the y-z planes, respectively, which is wide enough to cover the >; 0 dBi gain beamwidths of 120° for practical engineering applications.