Three-Dimensional Microwave Absorber based on Lossy Notch-Slot Resonator with Coupled Microstrip Line

A three-dimensional microwave absorber based on a lossy notch-slot resonator is proposed in this paper. Utilizing the resistor-loaded microstrip line coupling to the notch-slot, dualresonance can be obtained with a wide absorption band. The two resonances can be independently tuned by varying the length of the notch slot and the microstrip line. The proposed absorber exhibits an absorption band $(\vert \mathrm{S}_{11}\vert \leq-10\text{dB})$ from 3.7 GHz to 5.9 GHz, which is 46% FBW.