Broadband Polarization Insensitive Angular Stable Cross Dipole Loaded Circular Ring Circuit Analog Absorber (CAA) for X to K-Band Applications

This work presents a single-layered broadband polarization-insensitive circuit analog absorber for X to K-band applications. The design is made of a circular ring resonator loaded with four lumped resistors and a circular-split cross dipole, printed on the top of a dielectric substrate terminated with the ground. In the azimuthal plane, the proposed structure is insensitive to different polarization angles of the electric field due to the four-fold symmetry, and it also demonstrates a stable absorptivity up to 45° for both Transverse Electric (TE) and Transverse Magnetic (TM) incidences in the elevation plane. Multiple plasmonic resonances are responsible for the broadband behaviour, and the ohmic losses in lumped elements are the reason for near-unity absorption over the broadband. The response of the proposed equivalent transmission line model is validated with the full-wave analysis up to a reasonable extent. To the best of authors knowledge, this design is angular stable absorbing metasurface operational with limited chip resistors over broadband without compromising the performances, and it is suitable for the applications like Radar Cross Section (RCS) reduction and RF energy harvesting.