A Simultaneous Beam Steering and Polarization Converting S-Band Transmitarray Antenna

In this paper, a multi-functional transmitarray antenna consisting of miniaturized unit cells for S-band radar applications is proposed. The unit cell size is
$0.4\lambda _{0}\,\,\times \,\,0.4\lambda _{0}$
, and it is composed of a receiving (Rx) antenna, a miniaturized inductively-loaded reflection-type phase shifter, a PIN diode switch for polarization conversion, and a dual-polarization transmitting (Tx) antenna. The types of Rx and Tx antennas are coupled-fed stacked patch antennas. The designed reflection-type analog phase shifter has a 36 % smaller area than the conventional reflection-type hybrid coupler-based phase shifter. It has a 3-bit phase-shifting capability realized with a 0 ~ 330° analog phase shifting. The designed SPDT PIN diode switch can select the polarization of the transmitted wave and accept a high input RF power of 23 dBm. The proposed 8
$\times8$
transmitarray antenna with F/D of 0.33, made from its unit cell, has a gain of about 7.9 dBi and performs 90° 2D beam steering for vertical-to-horizontal and vertical-to-vertical polarization conversions at the center frequency.