Multistate active control RCS signature for the continuous adjustment absorber/reflector transformation applications

Abstract

Smart structures with tunable electromagnetic characteristics are required for camouflaging high-value targets, such as land warfare moving equipment, in continuously changing complex electromagnetic environments. The targets must control their radar cross section (RCS) to avoid detection and tracking. Frequency selective surfaces (FSSs) are the next-generation smart structures in which active RCS control is realized via impedance loading. In this paper, a multistate transformable FSS absorber/reflector that operates in the 3.9–11.0 GHz band is introduced and analyzed. The reflectivity amplitude of this absorber/reflector could be smoothly changed from 0 to -10 dB in 6.0-8.0 GHz. Each unit cell of the FSS structure consisted of four symmetrical diamond-shaped patterns, and the adjacent units were connected by PIN diodes. The absorption intensity of the FSS could be changed from 0 to -10 dB by adjusting the PIN bias voltage, which was applied via a simple bias network. The multistate switching characteristic of the FSS was verified by simulations and measurements. The results showed that adjustable absorbing intensity and switchable working states are the desirable characteristics that allow high-value targets to adapt to changing electromagnetic environments. Our work will bridge the gap between the available stealth strategies and practical applications, such as moving stealth vehicles.

Design of a broadband multifunctional switchable absorber/reflector based on active frequency selective surfaces

“…Active absorbers based on FSS, which combine two different functions and can generally be switched primarily from the absorbing state to other states, are proposed to obtain dynamic characteristics. As of now, most scholars are working on three types of absorption switches: absorbers/reflectors [15][16][17][18][19][20][21], absorbers/ radiators [22], and absorbers/transmitters [23,24]. Among them, the switchable absorber/reflector integrating two opposite functions plays a vital role in military stealth, which can hide the object in a wide bandwidth to avoid detection by the enemy in the absorbing state and can declare itself by flashing periodically in the reflecting state.…”

“…In recent years, a considerable number of switchable absorber/reflector designs have already been reported [15][16][17][18][19][20][21]. A frequency reconfigurable metamaterial absorber/reflector with eight modes of operation has been proposed in the literature [15], which is based on a strategically arranged structure of three-dimensional feed network and load switching diodes to realize the switching of single-band, dual-band, and triple-band.…”

“…The absorber/reflector's wideband and switchable properties in complex electromagnetic environments make it a promising candidate for stealth systems. The broadband switchable absorbers/reflectors are developed in [17][18][19][20][21], making significant progress in broadband switching characteristics. Nonetheless, these functionalities are limited to specific polarization.…”

Transparent and broadband switchable absorber/reflector based on structured water medium

“…To introduce switching or tuning capabilities, many reconfigurable absorbers are developed based on active frequency selective surfaces (AFSSs) [7][8][9][10][11]. Among them, switchable absorber/reflector devices are highly demanded in smart stealth systems to obtain an intentional modification of the target RCS through switching from a low visibility condition to a high visibility one [12][13][14][15][16][17]. A typical configuration to attain broadband switchable properties relies on AFSSs.…”

Characteristic Mode Design of Dual-Band Multistate Tunable Absorber Based on Programmable Flexible Metasurface

“…Recently, there has been an increasing interest in reconfigurable metasurfaces for variable absorption [19]- [31]. The flow of liquid crystal molecules was employed to switch the absorption and transmission states of visible light [19], [20],…”