Great Wall-like Water-based Switchable Frequency Selective Rasorber with Polarization Selectivity

TL;DR

This paper introduces a water-based, switchable frequency selective rasorber with polarization selectivity, capable of operating in four states, verified through prototype testing for potential radome applications.

Contribution

It presents a novel water-based, reconfigurable FSR with polarization control and switchability among four states, including a prototype validation.

Findings

Achieved polarization-intensive FSS with -0.42 dB passband at 3.75 GHz.

Demonstrated FSR with -10 dB band from 6.8 to 18.8 GHz and polarization selectivity.

Developed an automatic control system for water-based reconfiguration.

Abstract

A water-based switchable frequency selective rasorber with polarization selectivity using the Great Wall structures is presented in this paper. The proposed structure comprises a container containing horizontal and vertical channels enabling dividable injection of water, and a cross-gap FSS. The novelty of the design lies in its switchability among four different operating states by injecting water or not into the water channels. When the container is empty, the structure acts as a polarization-intensive FSS with a -0.42 dB insertion loss passband at 3.75 GHz. When the horizontal channel is filled with water and there is no water in the vertical channel, this structure can be used as an FSR with single polarization selectivity. The FSR with -10 dB absorption band from 6.8 GHz to 18.8 GHz only allows certain polarized electromagnetic (EM) waves to pass at 3.1 GHz with an insertion loss of -0.78 dB, while another polarized EM wave cannot pass. When the container is full of water, the structure operates as an absorber with a reflection band below the absorption band, where neither of polarization EM waves can transmit. Besides, a reconfigurable water-based FSR automatic control system is built to achieve state switching and temperature constancy of the water within the container. Ultimately, a prototype of the presented design is fabricated, simulated and measured to verify the feasibility. This work has potential application in radome design to realize the out-of-band RCS reduction.