Analysis and design of wideband transmitarray antennas with different unit-cell phase ranges

Despite the numerous advantages of planar transmitarray antennas over conventional lens antennas, transmitarrays have a narrow bandwidth. The goal of this paper is to present a design methodology for improving the bandwidth of transmitarray antennas through control of the transmission phase range of the transmitarray elements. Two Ku-band transmitarrays using quad-layer double-square loop elements, which differ in the transmission phase ranges, have been designed and compared. It is shown that the transmitarray antenna designed using the proposed methodology achieves a 10.1% bandwidth as compared to the 7.0% bandwidth of the conventional design.