Profile reduction of folded transmitarray antenna using multiple feeders

In this paper, we introduce a novel design for a high-gain, low-profile quad-feed folded transmitarray antenna (FTA) to enable a more compact system. The proposed antenna system consists of a transmitarray, a reflectarray, and four identical planar microstrip U-slot patch antennas placed on the same surface of the reflectarray with an adjacent distance greater than 1 . To compare the effectiveness of our design, we developed three different antenna array systems with the same aperture size: a single-feed transmitarray antenna (TA) system, the proposed quad-feed FTA system, and a single-feed FTA system. Our experimental results demonstrate that employing four symmetrical feeders with an adjacent distance of 3.2 effectively reduces the height by about 76.7 % in comparison to the height of a single-feed TA, and by 30 % when compared to the height of a single-feed FTA. We also present the design, fabrication, and testing of a prototype of the proposed quad-feed FTA operating in the Ku-band. The measured results of the prototype confirm the effectiveness of our design.