Wideband High-Efficiency Circularly Polarized Transmitarray With Linearly Polarized Feed

By using the low-loss element design method, a wideband high-efficiency transmitarray antenna with the linear-to-circular-polarization transformation is presented. The element is composed of a linearly polarized U-slot patch antenna and a circularly polarized single-arm Archimedean spiral antenna, and has the advantages of low insertion loss and good incident angle stability over a wide frequency band. The 0.14-λ
₀
-thick 1613-element transmitarray is fabricated using standard PCB technology, and presents a measured peak gain of 31.8 dBi with the corresponding aperture efficiency of 60.2%. The measured 1 dB gain bandwidth is 15.2% from 18.25 to 21.25 GHz. Simple structure, high performance, and low complexity make it an attractive candidate for the low-cost, high-gain circularly polarized antenna.