A Linear to Circular Polarization Converter with Angular Stability for K/Ka Applications

This paper presents a novel dual-band linear to circular polarization converter, operating at 19.6 to 20.3 GHz and 29.8 to 36.2 GHz, especially for satellite communication applications. Based on the theory of resonant circuits, the unit cell consists of two identical rectangular strips with thin split slots arranged in four layers, which are separated by the air space. The design realizes the conversion of the Linearly Polarized (LP) wave to the Right-Hand Circular Polarized (RHCP) wave at the lower band and the Left-Hand Circular Polarized (LHCP) wave at the upper band. Under normal incidence, the simulated insertion loss of the passbands is no more than 1 dB. The frequency range of the axial ratio on the threshold of 1 dB covers the operated bands. Furthermore, the performance against large incident angles is also demonstrated. An AR lower than 3 dB across the targeted frequency bands is achieved under incident angles up to 45°.