# Water-based Reconfigurable Frequency Selective Rasorber with Thermally Tunable Absorption Band

## TL;DR

This paper introduces a water-based reconfigurable frequency selective rasorber with thermally tunable absorption, capable of switching between absorbing and transmitting states, and adjustable absorption bands via water temperature, suitable for microwave applications.

## Contribution

It presents a novel water-based FSR with thermally tunable absorption bands and reconfigurable electromagnetic wave absorption and reflection capabilities.

## Key findings

- Achieves high absorption from 8.3 to 15.2 GHz
- Maintains stable passband at 5.2 to 7.0 GHz
- Prototype experiments confirm simulation results

## Abstract

In this paper, a novel water-based reconfigurable frequency selective rasorber (FSR) at microwave band is proposed, which has a thermally tunable absorption band above the transmission band. The water-based FSR consists of a bandpass type frequency selective surface (FSS) and a 3D printing container. The water substrate is filled into the sealed space constructed by the above two structures. The numerical simulation results show that the FSR can achieve absorption with high absorptivity from 8.3 to 15.2 GHz, and obtain a transmission band of 5.2 to 7.0 GHz. The minimum insertion loss of the transmission band reaches 0.72 dB at 6.14 GHz. In addition, the FSR has the reconfigurable characteristics of absorbing or reflecting electromagnetic waves by filling with water or not. The proposed water-based FSR shows its good transmission/absorption performance under different polarizations and oblique incident angles. Due to the Debye model of water, the absorption band can be adjusted by water temperature, while the passband remains stable. At last, prototype of the FSR based on water has been fabricated, and the experimental results are presented to demonstrate the validity of the proposed structure.

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Source: https://tomesphere.com/paper/1907.02630