A Design of Dual-Band Dual-Sense Circularly Polarized Folded Transmitarray Antenna for Ku-Band Satellite Communications

This paper introduces a design of dual-band dual-sense circularly-polarized (CP) folded transmitarray antenna (FTA) for Ku-band satellite communications. It consists of a single linearly-polarized (LP) source, a polarization-rotation reflecting surface (PRRS), and a receiver (Rx)-transmitter (Tx) meta-surface (RTMS). The PRRS composed of step-shaped patches is used to reflect x-polarized waves and convert <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> to y-polarization over a wide frequency range. The Rx layer of RTMS is an array of rectangular patches, which completely reflects the x-polarized waves, but allows the y-polarized waves to pass through. The Tx layer of RTMS is an array of slotted circular patches, which is designed for LP-to-CP conversion and phase compensation. The Rx and Tx patches are connected together by metallic vias and they are adjusted to generate right-hand CP at 12 GHz and left-hand CP at 14 GHz. The final design reduces the height-to-diameter (H/D) ratio by 2/3 compared to the traditional transmitarray antenna, while achieving the peak realized gains of 16.76 and 19.4 dBi at the lower and upper bands, respectively.