A Dual-Polarized Broadband Switchable Frequency Selective Rasorber/ Absorber

Abstract

In this paper, a dual-polarized active switchable frequency selective structure loaded with PIN diodes has been designed. The proposed geometry switches the working states between a rasorber and an absorber during OFF and ON states of the diode, respectively. The topology is double-layered; the top lossy layer is made of a swastika-shaped cross-dipole geometry with embedded lumped resistors, whereas the bottom layer has a slot geometry loaded with PIN diodes. These diodes are soldered across the slot to exhibit the switching property. During absorption mode, a wide bandwidth having absorptivity above 90% is achieved for the range 4.39 GHz to 13.16 GHz. During the rasorber mode, the absorption bandwidth remains almost constant, whereas an additional transmission peak appears at 12.78 GHz. The proposed design is also made compact, with the unit cell dimensions $0.145 \lambda_{L} \times 0.145 \lambda_{L}$, where $\lambda_{L}$ designates the operating wavelength at the lowest absorption frequency (4.39 GHz).