Triband Ultrathin Polarization Converter for X/Ku/Ka-Band Microwave Transmission

In this letter, a polarization converter is proposed for triband simultaneous microwave transmission in X, Ku, and Ka bands. It converts the incident linearly polarized (LP) waves into transmitted circular polarized (CP) waves in three frequency bands. The unit cell of the converter is composed of ultrathin bilayered metasurface having a thickness of about λ/40, patterned with a square ring and five squares conductor patches diagonally intersecting each other. The step-by-step design guideline for LP-to-CP conversion is presented with a converter example whose operational bands are 7.317-9.58, 25.45-31.4, and 35.37-42.167 GHz. To verify the design, a sample consisting of 20 × 20 elements is fabricated using a standard printed circuit board (PCB) fabrication process and tested inside the anechoic chamber. Close agreement between the simulated and measured results depicts the validity and reliability of the proposed design.