Fully Metallic Dual-Band Linear-to-Circular Polarizer for K/Ka-band

A dual-band polarizer is presented that converts linear polarization into circular polarization with orthogonal handedness in the satcom bands 19.7-20.2 GHz and 29.5-30 GHz. The polarizer consists of three identical cascaded perforated metallic screens, whose perforations are periodically repeated crosses of two sizes. Unlike previously reported dual-band polarizers, our design is fully metallic, which results in low losses and makes it suitable for space applications. A prototype of the polarizer with 20 x 20 unit cells is manufactured, and the measurement results agree well with the simulated results. In the nominal satcom bands, the measured axial ratio and the insertion loss are better than 1.7 and 0.67 dB. In the bands 18.9-20.3 GHz and 29.1-30.1 GHz, the measured axial ratio and insertion loss are below 3 and 1 dB.