Design of a Single-Layer Circuit Analog Absorber Using Double-Circular-Loop Array via the Equivalent Circuit Model

A broadband Circuit Analogue (CA) absorber using double-circular-loop array is investigated in this paper. A simple equivalent circuit model is presented to accurately analyze this CA absorber. The circuit simulation of the proposed model agrees well with full-wave simulations. Optimization based the equivalent circuit model, is applied to design a single-layer circuit analogue absorber using double-circular-loop array. Simple guidelines for designing the CA absorber are then formulated. It is demonstrated that the fractional bandwidth of 125.7% is realized for at least 10 dB reflectivity reduction with angular stability to 40˚ for both TM and TE modes. The total thickness of the absorber design is 0.093λL at the lowest operating frequency.