Abstract
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° 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° tilt angle. Simulations are presented for Ant-2. Compared to literature, both antennas show various improved results.
Highlights
With the rapid development in stealth technology, it is becoming increasingly important to develop antennas compatible with low radar cross section (RCS) platforms
The design of Ant-1 is based on three unit-cells, artificial magnetic conductor (AMC)-1, AMC-2 and frequency selective surface (FSS)-grad
Wideband RCS reduction has been achieved for arbitrary polarizations (105.8%)
Summary
With the rapid development in stealth technology, it is becoming increasingly important to develop antennas compatible with low radar cross section (RCS) platforms. Antennas can backscatter large amounts of radar waves and can enhance the likeliness of a stealth target to be captured on a radar [1], [2]. The associate editor coordinating the review of this manuscript and approving it for publication was Chan Hwang See. To outdo this, several techniques have been employed for RCS reduction of antennas. A prime factor to determine the suitability of a technique to be adopted for lowering the RCS of antenna depends on how it affects the antenna’s radiation performance. It is desired that the antenna’s performance remains unaffected/intact, while RCS reduction is achieved over a wideband (in-band + out-of-band frequencies). Artificially engineered surfaces, generally known as metasurfaces, have
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