Design of Polarization-Insensitive Dual band Microwave Absorber for EMI/EMC Applications

A novel design of miniaturized dual-band microwave absorber is introduced in this work. The absorber unit cell is comprised of the two metal-based structures placed on the top of a metal-backed dielectric substrate. The structure gives two transmission nulls and two reflection nulls at 3.52 GHz and 7.48 GHz that exhibiting two absorption peaks at those frequencies which correspond to Wi-MAX and X-band satellite/spacecraft communication frequencies accordingly. The size of the microwave absorber unit cell has dimensions of 0.258λ × 0.258λ, where λ indicates the wavelength of the free space associated with the resonance of lowest frequency. The structure is insensitive to polarization and shows stable response for the propagation of electromagnetic wave in both TE mode and TM mode under oblique incidence up to 900. The proposed design will be useful for effective electromagnetic shielding thus finding its application in electromagnetic interference (EMI) and Electromagnetic compatibility (EMC) cases.