A Miniaturized Low-profile Dual-polarization Frequency-selective Rasorber with Swastika Structure and Interdigital Resonator

The miniaturized dual-polarization low-profile frequency selective rasorber (FSR) with interdigital resonator is proposed, which exhibits two absorption bands on either side of the pass band. The lossy layer is a cross-shaped structure that two resistive sheets are loaded on both sides of the interdigital resonator. The lossless layer is a square ring gap structure. The design guideline is proposed to analyze its operating principle with the aid of an equivalent circuit model. The methods of meandering and interdigital resonator are used to achieve miniaturization. The dimension of element is
$0.087\lambda_{L}$
and the thickness is
$0.084\lambda_{L}$
where
$\lambda_{L}$
is the wavelength corresponding to the lowest working frequency. It is shown that an insertion loss of about −0.38dB is obtained at 10.6 GHz under normal incidence. The −3 dB transmission bandwidth is about 17% and the fractional bandwidth for reflection less than −10 dB is about 103%. The FSR show stable incident angles response from 0 to 30 degrees for both TE and TM polarizations.