Design of a Broadband Polarization Insensitive Circuit Analog Absorber for C, X and Ku- Band Applications

This work presents a broadband, polarization insensitive circuit analog absorber (CAA) featuring wide angular stability. Each unit cell of the proposed absorber consists of a simple ring-shaped geometry loaded with lumped resistors. The proposed design exhibits −10 dB absorption bandwidth from 6.26 to 17.89 GHz(11.63 GHz bandwidth and 96.31% fractional bandwidth), falling within the C, X and Ku frequency bands. The unit cell has circular symmetry, making it insensitive to polarization, and exhibits good angular stability up to 50° for both Transverse Electric (TE) as well as Transverse Magnetic (TM) modes. The design is compact, featuring periodicity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.219 \lambda_{L}$</tex> and thickness of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.089 \lambda_{L}$</tex>, where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{L}$</tex> represents the wavelength corresponding to the lowest operational frequency.