A Dual-Polarization Band-Absorptive Frequency-Selective Rasorber for S-Band Applications

This paper presents a dual-polarized band-absorptive frequency selective rasorber (FSR) for WLAN, Bluetooth, WiMAX, and WiFi applications. The FSR provides an absorption band and a lowpass band with low insertion loss below the absorption band. The structure consists of a lossy layer cascaded with a bandstop frequency selective surface (FSS). A Jerusalem-loaded square ring embedded with lumped resistors composes the top lossy layer. The bandstop FSS is realized by combining a square ring and a cross-dipole. Full-wave simulated results show that the FSR exhibits an absorption band (S
11
≤ −10 dB, S
21
≤ −10 dB) from 1.82-4.01 GHz (75.12%), covering the S-band with a thickness of 0.14λ
a
at 1.82 GHz. At the same time, it is almost transparent to the incident electromagnetic waves below 0.31 GHz (|S
21
| ≥ – 1 dB, S
11
≤ −10 dB). The structure is polarization-insensitive and exhibits a stable performance for oblique incidence up to 30 deg for dual-polarization. The proposed FSR can be deployed as radomes in military communications for low-frequency antennas.