Wide-angle beam-scanning transmitarray antenna with low scan loss

In this letter, a mechanical beam-scanning transmitarray antenna with a wide scan coverage is presented. A wide-band element is designed to provide a linear transmission phase shift with a low transmission loss, which comprises a double-arrow and two orthogonal grid polarizers printed on two substrates. Then, a dual-beam phase matching method is introduced to reduce the scan loss. To verify the design, a 437-element transmitarray with a circular aperture (D = 150 mm) is simulated, fabricated, and measured. The measured results indicate that the transmitarray antenna achieves a +/- 40 degrees scan coverage while keeping a low scan loss (<1.8 dB). The side lobe levels keep lower than -15 dB in the entire scanning range. Moreover, a 1-dB gain bandwidth of 21% (14-17.2 GHz) can be achieved in terms of boresight radiation, and the measured peak gain is 23.5 dBi at 15 GHz.