Screen-Printed Wideband Absorber for the $X$ and Ku Bands
Avinash Avinash, Nisha Gupta
Abstract
This article presents the design and analysis of a flexible wideband absorber comprising a resistive ring-shaped frequency-selective surface (FSS). In this article, a novel conductive material is used for the designing and fabrication of the absorber. The structure consists of two different-size rings arranged diagonally as an FSS and printed on a flexible photo paper substrate material using screen printing technology and backed with a copper ground plane. The unit cell dimension is 0.64 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\,\lambda _{l}$</tex-math></inline-formula> × 0.64 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\,\lambda _{l}$</tex-math></inline-formula> × 0.088 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\,\lambda _{l}$</tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{l}$</tex-math></inline-formula> is the wavelength at the lowest absorption frequency. The fractional bandwidth of the proposed absorber is 86.2%, which covers <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$X$</tex-math></inline-formula> and Ku bands completely and the lower portion of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> -band. The proposed absorber shows more than 90% absorption in the frequency range of 8–20.12 GHz at different angles of polarization. The effect of various design parameters of the FSS, such as period of unit cell, thickness of the substrate, interelement spacing, and width of the rings, is examined and verified based on the simulation, circuital, and experimental model.