A miniaturised frequency selective rasorber with wide transmission band

This paper demonstrates a miniaturised frequency selective rasorber (FSR) that incorporates meander cross-rings to realise a wide transmission band. The FSR comprises a resistive layer and a bandpass frequency selective surface (FSS), which are separated by an air layer. The resistive layer is constructed by employing meander cross-rings equipped with lumped resistances, where the inner arms of cross-rings are bent to obtain a parallel resonant circuit with large inductances and small capacitances to achieve broadband transmission at high frequencies. The bandpass FSS is implemented using a triple-layer metallic structure, where two identical square ring layers are coupled through a central metal grid layer to form the transmission band. The measured results indicate that the absorption band with absorptance exceeding 90% is from 3.5 to 9.4 GHz, and the passband exhibiting insertion loss of less than 1 dB spans from 11.92 to 17.98 GHz with a 40.5% relative bandwidth, which matches well with simulated ones. This FSR has the characteristics of simple structure and high performance, which provides a novel concept of stealth applications.