Low-Profile Dual-Polarization Frequency-Selective Rasorbers Based on Simple-Structure Lossy Cross-Frame Elements

Abstract

The low-profile dual-polarization frequency-selective rasorbers with very simple structures are investigated. Based on an equivalent circuit model, the operating principle and design method are first studied. One rasorber using lossy cross-frame elements and double-square loops is then proposed, which exhibits two absorption bands at the two sides of one passband. Moreover, the rasorbers with reduced cell size are further developed to stabilize the angular response. Under normal incidence, an insertion loss of about 0.26 dB is obtained at 4.25 GHz, the fractional bandwidth for reflection less than -10 dB is over 100%, and the thickness is around 0.1λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> .For demonstration, the rasorber prototypes are fabricated and measured, while reasonable agreements are observed accordingly.