Abstract

A tunable polarization-insensitive absorber based on an active frequency-selective surface is proposed for electromagnetic (EM) wave absorption in the L and S bands. The frequency-selective surface consists of a diamond-shaped loop that is interconnected by varactor diodes. The proposed design is significant because of its inclusion of wideband tuning and its ability to easily change from single-band tunable absorption to dual-band absorption. The simulation results demonstrate that the absorption response (> 80%) can vary from 1.62 GHz to 3.66 GHz under the reverse bias voltage, thus creating a tunable range of 125.9%. The absorption region (> 90%) spans from 1.86 GHz to 3.31 GHz and generates a 78% tunable range. The single-band tunable absorber is characterised by an equivalent circuit model to obtain the circuit parameters and predict the absorption frequency. Furthermore, a dual-band absorbing structure is obtained by adding a metasurface directly to the single-layer structure, which can easily be changed from single-band absorption to dual-band absorption by separately controlling the bias voltages of the upper and lower unit cells. The two fabricated prototypes were measured using free-space technology, and the experimental results closely mirror the simulation results. Results show that the proposed structure achieves the dynamic control of EM wave absorption.

中文翻译：

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使用有源频率选择表面的L和S波段可调谐偏振不敏感吸收器的设计

摘要

提出了一种基于有源选频表面的可调谐极化不敏感吸收器，用于吸收L和S波段的电磁（EM）波。频率选择表面由菱形的环路组成，该环路由变容二极管互连。所提出的设计具有重要意义，因为它包含宽带调谐功能，并且能够轻松地从单波段可调吸收变为双波段吸收。仿真结果表明，在反向偏置电压下，吸收响应（> 80％）可以在1.62 GHz至3.66 GHz之间变化，从而产生了125.9％的可调范围。吸收区域（> 90％）的范围从1.86 GHz到3.31 GHz，并产生78％的可调范围。单频带可调吸收器的特征在于等效电路模型，以获取电路参数并预测吸收频率。此外，通过将超表面直接添加到单层结构中来获得双带吸收结构，通过分别控制上下单元电池的偏置电压，可以容易地将超表面从单带吸收改变为双带吸收。 。两个制造的原型使用自由空间技术进行了测量，实验结果与仿真结果非常相似。结果表明，该结构实现了电磁波吸收的动态控制。通过分别控制上下单元电池的偏置电压，可以很容易地将其从单频带吸收改变为双频带吸收。两个制造的原型使用自由空间技术进行了测量，实验结果与仿真结果非常相似。结果表明，该结构实现了电磁波吸收的动态控制。通过分别控制上下单元电池的偏置电压，可以很容易地将其从单频带吸收改变为双频带吸收。两个制造的原型使用自由空间技术进行了测量，实验结果与仿真结果非常相似。结果表明，该结构实现了电磁波吸收的动态控制。