Wideband and Polarization Insensitive EM Absorber Using Tightly Coupled Dipole Structure

Abstract

This paper introduces a wideband resistive electromagnetic (EM) absorber surface that is based on a tightly coupled dipole structure with polarization insensitivity. By employing broadband tightly coupled dipoles as the fundamental units, the resulting array is capable of effectively absorbing spatial EM energy, while the incorporated resistors facilitate energy dissipation. To comprehensively understand the operational principles of the absorber surface, an equivalent circuit model is proposed in this study. To validate the absorber surface's absorption capabilities, a 290 mm × 290 mm EM absorber surface was manufactured and subjected to rigorous testing. The test results unequivocally demonstrated that the absorber surface achieved an absorption efficiency surpassing 90% within the frequency range of 3.38 to 10.3 GHz. Furthermore, the proposed absorber surface showcased remarkable insensitivity to changes in the incident wave's polarization angle. As the incident angle varied from 0° to 45°, the absorption efficiency remained consistently stable within the designated operating frequency band.