Low Profile Polarization-insensitive Multiple-band Metamaterial Absorber using a Slotted Octagonal Unit Cell

Abstract

This paper introduces a thin, polarization-insensitive (PI), and multiple-band electromagnetic metamaterial absorber (MMA). The unit cell of the MMA consists of a slotted octagonal metallic patch printed on an FR4 dielectric substrate, backed by a grounded metallic layer, and notably does not incorporate resistive lumped elements. The proposed MMA exhibits measured absorption, exceeding 75% for normal incidence, across frequency bands ranging from 2.22–2.38 GHz, 6.86–7.24 GHz, 11.68–12.71 GHz, 14.1–14.8 GHz, and 15.47–16 GHz. The proposed MMA unit cell has dimensions of 0.21λ0 × 0.21λ0 and a thickness of 0.001λ0, where λ0 represents the wavelength corresponding to the lowest frequency at 2.22 GHz. The performance of the proposed MMA is simulated using CST Microwave Studio and MATLAB, and subsequently validated through experimental measurements.