A Wideband High-Efficiency Circularly Polarized Transmitarray With Linear-to-Circular Polarization Conversion

In this letter, a wideband high-efficiency circularly polarized transmitarray antenna with linear-to-circular polariza-tion (LP-to-CP) conversion is proposed. The element consists of a wideband linearly polarized (LP) receiver and a circularly polar-ized (CP) transmitter, connected through a central metallized via. In the design, the transmission performance of the element is improved by adding parasitic patches to the main radiating patch. Moreover, the element employs a unique top-layer patch rotation method for precise phase compensation. The proposed LP-to-CP transmitarray achieves a 1 dB gain bandwidth of 26.1% and a peak aperture efficiency of 60.9%, outperforming most existing designs in terms of efficiency-bandwidth balance. The entire ar-ray is composed of 400 elements, with a total thickness of only 0.13 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula>. Experimental results demonstrate a peak gain of 26.7 dBic within the operational bandwidth, highlighting its potential for applications in satellite communication, radar, and other wireless systems.