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, H., Abdul Latef, T., Yamada, Y., Hassan, T., Wan Mahadi, W. N. L., Othman, M., Kamardin, K., Hussein, M. I.
• Format: Article
• Language: English
• Published: Institute of Electrical and Electronics Engineers Inc. 2021
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/94353/1/TarikAbdulLatef2021_FabryPerotAntennaEmployingArtificial.pdf; http://eprints.utm.my/id/eprint/94353/; http://dx.doi.org/10.1109/ACCESS.2021.3076913

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 0.33lambda , 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° 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 0.3lambda . 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° tilt angle. Simulations are presented for Ant-2. Compared to literature, both antennas show various improved results.