Absorptive Frequency-Selective Reflection and Transmission Structures

Abstract

Tailoring methodology is proposed in this communication to achieve arbitrary frequency response within a wide absorption band. An ultra-wideband absorber utilizing multiple resonances in the unit cell of 3-D frequency-selective structure is utilized as the textile for the proposed designs. Two types are proposed; one is absorptive frequency-selective reflection structure and the other is absorptive frequency-selective transmission structure. These structures have reflection/transmission band within a wide absorption band. Two prototypes are designed, fabricated, and measured to validate the proposed methodology. The first one is an ultra-wideband absorber with 155.7% absorption bandwidth from 1.8 GHz to 14.4 GHz with structure’s thickness of 0.12 λ0 at the lowest absorption frequency. The second one is an absorptive frequency-selective transmission structure with wide absorption bands at both sides of its transmission window. It exhibits 54% and 76% for the lower and upper absorption bands, respectively, with 1 dB insertion-loss in the transmission window. A good agreement is achieved between simulated and measured results.