A Circuit-Based Model for the Interpretation of Perfect Metamaterial Absorbers

作者：Costa, Filippo^*; Genovesi, Simone; Monorchio, Agostino; Manara, Giuliano

来源：IEEE Transactions on Antennas and Propagation, 2013, 61(3): 1201-1209.

DOI：10.1109/TAP.2012.2227923

• Electromagnetic absorbers
• high-impedance surfaces (HIS)
• infrared
• metamaterial absorbers
• radar absorbing material (RAM)
• terahertz absorbers

A popular absorbing structure, often referred to as Perfect Metamaterial Absorber, comprising metallic periodic pattern over a thin low-loss grounded substrate is studied by resorting to an efficient transmission line model. This approach allows the derivation of simple and reliable closed formulas describing the absorption mechanism of the subwavelength structure. The analytic form of the real part of the input impedance is explicitly derived in order to explain why moderate losses of the substrate is sufficient to achieve matching with free space, that is, perfect absorption. The effect of the constituent parameters for tuning the working frequency and tailoring the absorption bandwidth is addressed. It is also shown that the choice of highly capacitive coupled elements allows obtaining the largest possible bandwidth whereas a highly frequency selective design is achieved with low capacitive elements like a cross array. Finally, the angular stability of the absorbing structure is investigated.

• 出版日期2013-3