Executive Summary : | Microwave absorbers find commercial and military applications wherever electromagnetic reflections from surfaces have to be minimized. Ultrathin lightweight materials with high absorption over broad ranges of microwave frequencies such as the C or X bands are an essential part of stealth technologies used to minimize the reflection of the radar beam from an object’s surface. Typical microwave absorbers for stealth consist of rubberized matrices of ferrites/ferroelectrics that pose a large weight and thickness penalty. Recently, metamaterial absorbers have been projected for stealth/camouflage applications. Typical metamaterial absorbers have metallic structures, narrow-band in nature and not applicable to stealth applications. Investigators recently developed novel resistive ink or resistive sheet-based broadband metamaterial absorbers that cover entire C and/or X bands. These absorbers are advantageous as they are very thin, lightweight, compact and inexpensive. Here textile-based metamaterial absorbers are proposed, where the resistive ink would be printed on various types of clothes like cotton, canvas, tarpaulin, army fatigues etc. The metamaterial designs would be developed for different types of clothes and the designs will be screen-printed with conductive inks. These textile absorbers will provide broadband absorption in C and/or X-bands, which are particularly important for ground-based assets. The developed microwave absorbers will be worn by persons / wrapped around vehicles for performing field trials using RADAR / RF motion sensors to validate their use in stealth applications for ground assets. Development of these metamaterials would allow for their incorporation into helmets, bullet-proof jackets, skirting for tanks, armored carriers and other vehicles with the advantage that they can be blended in with presently available optical camouflage patterns. This technology is critically important for our armed forces and DRDO can be involved at a future stage. |