Fabry-Perot antenna employing artificial magnetic conductors and phase gradient metasurface for wideband monostatic RCS reduction and high gain tilted beam radiation

• Main Authors: Umair, Hassan, Latef, Tarik Bin Abdul, Yamada, Yoshihide, Hassan, Tayyab, Mahadi, Wan Nor Liza Binti Wan, Othman, Mohamadariff, Kamardin, Kamilia, Hussein, Mousa I.
• Format: Article
• Published: Institute of Electrical and Electronics Engineers 2021
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/34059/

Platforms with low radar signatures require compatible antennas (low scattering) for communication purposes. Under this context, the article presents two Fabry-Perot (FP) Cavity antennas (Ant-1 and Ant-2). Ant-1's aperture is an integrated design of artificial magnetic conductor (AMC) surface and a phase gradient metasurface (PGM), incorporating three unit-cell structures. The antenna achieves reduced monostatic scattering over broad bandwidth, and simultaneously obtains high gain as well as tilted beam peak radiation. Patch radiating at 7 GHz forms excitation source of the cavity, and cavity height is 0.33 lambda, smaller than the heights of conventional cavity designs (lambda/2). RCS reduction is obtained over a bandwidth of 105.8% (4-13 GHz) for arbitrary polarizations, covering C/X bands. Antenna gain is 12 dB, and peak radiation tilt is -60 degrees in elevation plane. Simulations have been verified through fabricated prototype. Ant-2 is a modification of Ant-1. Ant-2's aperture is constructed from two unit-cell structures, and its aperture size is 41% smaller than Ant-1. Its cavity height is 0.3 lambda. Ant-2 also achieves wideband backscattering reduction; however, due to asymmetric layout of unit-cell elements over the aperture, radar cross section (RCS) reduction bandwidth is different for the two polarizations. For vertically polarized (VP) incident wave, RCS reduction bandwidth is 105.8% (4-13 GHz), but for horizontally polarized (HP) wave, it is 85.7% (5.2-13 GHz). Nevertheless, broadband RCS reduction is still achieved for both polarizations. Peak gain is 11.73 dB, achieved at -37 degrees tilt angle. Simulations are presented for Ant-2. Compared to literature, both antennas show various improved results.