Miniaturized electromagnetic absorber for millimeter-wave RADAR systems

This research investigates the design of a novel planar millimeter (mm)-wave absorber for RADAR application. The proposed mm-wave absorber is constructed using integrated and distributed elements to reduce the complexity of the design. The proposed absorber exhibits a dual resonance by exploiting the mutual coupling between two concentric square rings. The impedance matching is achieved by introducing corrugations between the square rings. The mm-wave absorber operates in the frequency range of 31.4–33 GHz (1.64 GHz) with a minimum absorptivity of 95–100%, respectively. The performance of the proposed absorber is demonstrated using equivalent circuit modelling. Owing to the symmetric nature of the unit cell, the proposed absorber offers stable performance for both TE and TM modes of operation. The prototype of the proposed absorber is fabricated on a single-layered FR-4 substrate with a thickness of λ 0 5.97 and periodicity of λ 0 1.91 , where λ 0 is free space wavelength at the lowest resonant frequency. The observed result is validated using experimental measurements in free space and has good agreement with the simulated results. Hence, the proposed mm-wave absorber is a promising entity for stealth engineering in military and defense systems.