An FSS-Backed Broadband Phase-Shifting Surface Array With Multimode Operation

This paper presents a novel broadband phase-shifting surface (PSS) element with frequency-selective surface (FSS) backing, which could independently control the phase of transmitted/reflected waves at high/low frequencies. Using the appealing features of basic building block, a high gain planar array antenna is designed and implemented by employing a set of these spatially varied phase-shifting elements. Fed by a Vivaldi antenna, the fabricated array is composed of 9 × 9 elements, each carefully designed to exhibit the desired transmission/reflection phase at high/low frequencies. Numerical and experimental results indicate that the fabricated array is capable of showing the functionalities of transmitarray and reflectarray at different frequencies. The peak gain of either transmission or reflection beam was found to be 18.8 dB, which was at least 10 dB higher than that of bare feed source.