A Ka-band Electromagnetic Absorber based on Loaded Ring Slots

This paper presents the design of a frequency-selective absorber based on resistive loaded ring slots. The absorber consists of two layers separated by a dielectric substrate. One layer contains periodic annular ring slots loaded with four lumped resistors symmetrically distributed along the ring, while the second layer consists of a metallic screen. Simulation results show that the designed Ka-band absorber provides an absorption coefficient higher than 0.9 from 31.8 to 34.1 GHz and is suitable for both linear and circular polarizations of the incident electromagnetic wave.