Low-Cost Wide-Angle Beam-Scanning Transmitarray Antennas Using Lens-Loaded Patch Elements: A Proof-of-Concept Study

Abstract

In this letter, a novel design concept to achieve a low-cost wide-angle beam-scanning transmitarray (TA) using lens-loaded patch (LLP) elements is presented. In this design, each TA element consists of a beam switchable transmitting element, a group of receiving elements, and a signal via. The received powers of a 2×2 subarray are first combined and then transmitted to the corresponding LLP element, where the phases of the transmitted signals are manipulated for beamforming. Compared with the conventional designs, the phase shifters (PSs) can be multiplexed and the number of PSs is effectively eliminated by 75%, which significantly decreases the hardware cost. By employing multiple patches as the feed of the lenses, reconfigurable radiation patterns are obtained, and by properly choosing the transmitting patches, the developed TA achieves a wide-angle two-dimensional beam scanning within ±60° with stable gains. To validate the design concept, passive prototypes with a center frequency of 12.5 GHz are simulated, fabricated, and tested. The measured results show that the aperture efficiency is 30.1%, 19.4%, and 14.1% for beams steered to 0°, 30°, and 60° at 12.5 GHz, respectively. The beam coverage of ±60° with a less than 3.5 dB scanning loss in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -plane is obtained.