A High-Efficiency Transmit–Reflect Array With Independent Beam Control

This communication presents a novel dual-functional transmit-reflect-array (TRA) antenna that allows for independent control of transmission and reflection beams. The TRA antenna operates as a transmitarray with polarization conversion at 17 GHz, converting <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>-polarized incident waves into <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i>-polarized transmissions while providing full 360° phase shift range. Additionally, it functions as a reflectarray at 33 GHz, preserving the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>-polarization properties with full 360° phase coverage. Importantly, the element response in the reflection mode is independent of that in the transmission mode, which is achieved through a dual-band decoupling optimization strategy. Furthermore, the proposed element has a simple triple-layer structure without air gaps or metallic vias, exhibiting enhanced efficiency and reduced fabrication cost. To validate the design concept, a TRA prototype with a diameter of 264 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mm</i> was fabricated and measured. The transmitarray mode achieves a peak gain of 30.91 dBi (with an aperture efficiency of 56.9%) at 17.0 GHz, while the reflectarray mode achieves a peak gain of 35.79 dBi (with an aperture efficiency of 47.5%) at 32.9 GHz. This dual-band, dual-mode TRA antenna enables new possibilities for advanced wireless communication and radar applications.