A Low-Profile and Ultrawideband Capacitive Circuit Absorber Empowered by Enlarged Unit Periodicity
Ting Shi, Ming‐Chun Tang, Jianing Yang, Xuesong Yuan
Abstract
In this letter, alow-profile and ultrawideband capacitive circuit absorber with enlarged unit periodicity is developed by using impedance sheet model for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> synthesis and grating lobes suppression. The developed absorber achieves a simulated (measured) 10 dB absorption bandwidth ratio of 12.4:1 (12.5:1) at 0.093 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> , and its unit size is 0.3 × 0.3 × 0.093 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> corresponds to the lowest 10 dB absorption frequency. By taking advantage of the enlarged unit periodicity to directly improve realizable capacitance diversity, the developed absorber can be realized conveniently without high dielectric substrate and complex frequency selective surface patterns, which makes it lightweight, cheap, easy to design, and thus, suitable for many low-frequency applications.