A comparative study between different approaches to improve the RCS of a compact double-layer absorber

Abstract

In this paper, straightforward and efficient techniques have been addressed into double-layer structure to enlarge the operating bandwidth to include the X, Ku and K bands, in addition to increase the electromagnetic wave absorption for wide varieties of incident angles and both polarization types. To increase the band-stop resonating frequency up to 26 GHz, an additional layer of meta-surface, circuit analog radar absorber material (CAR), or a thin radar absorber material (RAM) layer is engineered. The synthesized layers are designed based on optimization process with genetic algorithm (GA) through numerical technique (Ansoft design software HFSS) for both transmission line (T.L) and the free space method to get optimal material properties suitable for the design. For different approaches, the designed structures achieved a reflectivity value less than −16 dB on average in the desired bandwidth from 8 to 26 GHz for TE/TM modes with incidence angle up to 50̂.

Design of compact multi-layer microwave absorber for ultra-wide band applications thru shaping and RAM technologies

“…The first layer is a rubber ferrite composites made up of ferrimagnetic powders and rubber as a host material used for confining incident wave through the overall structure. The second one is composed of a rubber compounds loaded with a conductive powders to have specular RCS attenuation properties over a wide frequency range (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). The measurements of the third layer material properties are compared to the numerical results for both WR-90 and microstrip line models to check the validity of the design.…”

“…In order to improve the designed compact double-layer structure absorptivity presented in [14,15], three significant approaches with illustrative RCS for both normal and oblique incident angles, have…”

Passive techniques for target radar cross section reduction: A comprehensive review

“…Recently, in Reference 12, Ji et al have used plasma and metamaterial as coating layers defined and analyzed by finite‐difference time‐domain (FDTD) method for RCSR of a cylinder. Similar to the shaping methods, coatings suffer from narrow RCSR bandwidth and high fabrication complexity. Using absorbent materials : absorbent materials (ie, radar absorbent material (RAM), 13‐22 microwave‐absorbing material (MAM), 21,23‐27 high impedance surface (HIS), 28‐30 and metamaterial absorber (MA)/ perfect metamaterial absorber (PMA) 31‐45 ) have been studied since 1950s 1 . These materials are lossy layers loaded on the target 46 which absorb the incoming EM energy and transform it into heat so that the backscattered EM wave to the radar receiver is decreased.…”

“…Afterward, several RAM and MAM structures have been proposed and developed for RCSR in a wider range of frequency with different numbers of layers 19,20,26 . Recently, a comparative study has been conducted in Reference 21 between different approaches of RAM structures whose reflectivity value was less than −16 dB on average in a frequency band of 8 to 26 GHz for TE/TM modes and incident angles up to 50°.…”

Low radar cross section microstrip antenna based on left‐handed material

“…Several methods have been proposed recently to reduce antenna RCS, including metamaterials, loading PIN diodes, frequency selective reflector, characteristic mode analysis, shaping methods, and so on. Metamaterials offer the advantage of controllable electromagnetic properties and have been widely used to reduce antenna RCS.…”