Switchable Low-Profile Broadband Frequency-Selective Rasorber/Absorber Based on Slot Arrays

Switchable low-profile broadband frequency rasorber/ absorber based on slot arrays is presented and investigated. First, an equivalent circuit model is proposed to synthesize a rasorber with the transmission window within the absorption band. Based on the slot arrays, simple design guidelines for rasorber design are further developed. Low-profile broadband rasorber and high-selectivity rasorber are, respectively, designed and analyzed to verify the design strategies. Moreover, by loading the switching diodes, a switchable rasorber/absorber is proposed and analyzed, which exhibits small insertion loss at the transmission window and a bandwidth around 100% while the thickness is less than 10% of the free-space wavelength at the lowest operating frequency. Moreover, one extension of dual-polarized rasorber is also designed and analyzed to further validate the design strategy. For demonstration, the rasorber prototypes are fabricated and measured, good agreement between the simulation and measured results is observed.