Sliding the Radiating Aperture of Multi-Beam Transmitarray with Low Scan Loss

Abstract

The transmitarray plays an important role in high gain antennas with beam steering abilities. However, multi-beam transmitarray suffers high scan loss when identical radiating aperture is shared among multiple feeding ports, i.e., lower gain is achieved with larger beam steering angle away from the normal direction to the transmitarray. For this reason, the sliding aperture technique is adopted and discussed in this paper. Each feeding port illuminates a segment of the overall aperture, and each segment is with nearly perfect transmitting phase distribution according to its feeding port for low scan loss, i.e. stable gain. Then, a linear multi-beam transmitarray based on the sliding aperture technique is numerical studied for the first time, to the best of the authors' knowledge. The numerical results show that the antenna can generate six beams covering $\pm 32.5^{\text{o}}$ azimuthal area with gain variation less than 1 dB, and all ports have good matching and high isolation in operating band.