A Miniaturized Microwave Absorber based on Interdigital Capacitor and Lumped Resistance for X-Band Radome Applications

In this work, a polarization insensitive compact X-band microwave absorber with miniaturized electric field coupled (ELC) resonator is presented. The ELC resonator is integrated with interdigital capacitor for synthesis of miniaturized unit cell area. The structure is also loaded with lumped resistances to achieve wideband absorption. The absorption band with more than 90% absorption covers mostly X-band frequencies from 8.16 GHz to 12.16 GHz with relative absorption bandwidth (RAB) of 39%. The size of the unit cell is 0.16 λL × 0.16 λL and overall thickness of the structure is only 3 mm (0.08 λL, with respect to lowest resonance frequency). The simulated absorption performances of the proposed miniaturized absorber are analyzed for different incident and polarization angles and found to be insensitive and hence can be well suited for Radome application.