Wide Band Microwave Absorber using Flexible Broadside Coupled Split Ring Resonator Metamaterial Structure

This paper proposes a wide band microwave absorber in a bulk form realized using a Broad Side Coupled Split Ring Resonator (BCSRR) metamaterial structural units fabricated in a novel way which possesses structural flexibility and wide band frequency tunability. Instead of using a conventional structure, the two conducting rings of the structure are prepared separately by photochemical etching using thin copper sheets glued on polypropylene film. The resonant property studies of the BCSRR show a noticeable tunability in resonant frequency with spacing variation, a result not observed using other conventional SRR structures. A spacing variation of 1 mm of a typical BCSRR unit shows around 3 GHz resonant tunability which makes it suitable for materializing various sensor applications. The resonant properties of BCSRR in a bulk form made with specific structural dimensions arranged in periodic manner with progressively varying spacing using layers of cotton fabric, show wide band resonant absorption. By suitably modifying the structural parameters of BCSRR rings, the range of the frequency absorption band can be specifically designed. The result of the study predicts a possibility of using this proposed BCSRR designs in various types of wide band absorbers.