A WIDEBAND TRANSMITARRAY USING DOUBLE-PETAL LOOP ELEMENTS

In this letter, a four-layer transmitarray operating at 9.5 GHz is designed using a double- petal loop element as the unit cell. A configuration of the double-petal loop elements is used to increase transmission phase variation while maintaining a wide transmission magnitude bandwidth of the unit cell, and a full transmission phase range of 360 ◦ is achieved for a transmission magnitude equals to or better than −2.4 dB. Furthermore, the oblique performance of the unit cell is also good. Then, a prime- focus 676-element microstrip transmitarray with the proposed element is fabricated and measured. The highest measured gain is about 22.15 dBi at 9.8 GHz, resulting in a 31% aperture efficiency. The antenna bandwidth of 10.2% (from 9.3 to 10.3 GHz) for 1-dB gain is achieved in this design.