Profile-Reduced S/X-Band Shared-Aperture Antenna Array with Frequency-Selective Surfaces

Shared-aperture antennas (SAAs) are becoming more popular due to their desirable traits such as miniaturization and multi-band operation. However, achieving adequate SAA performance often requires a high total antenna profile or costly manufacturing. In this work, we review the state-of-the-art SAAs and present the design concept and simulation results of a novel dual-circularly polarized SAA for satellite communications. The S-band element is realized with a band-to-band isolating dipole, and the steerable X-band array utilizes slot antennas as radiating elements. An artificial magnetic conductor (AMC) reflector is employed to manage reflection phases, enabling a reduced total antenna profile of 0.083λ at the lowest operation frequency, and co-planar placement of the S-band and X-band elements. This architecture utilizes a single, cost-effective two-layer PCB shared by both the low-band and high-band radiating elements, reducing manufacturing costs and time. The SAA simulations indicate a −10-dB total active reflection coefficient bandwidths of 20.7% for the S-band and 13.7% for the X-band array broadside
beam. The axial ratio (AR) is less than 1 dB for the broadside beam across the target band for both the S-band and X-band, and the AR remains below 3 dB for the X-band array when steering ±40° in the principal and diagonal planes.