In this letter, a new polarization-insensitive, low profile frequency-selective rasorber (FSR) is presented with a switchable transmission band. This FSR consists of a lossy layer, a bandpass layer, and a switchable layer where p-i-n diodes are mounted and parallel fed. The lossy layer is composed of compact fractal elements with lumped resistors, which miniaturizes the unit dimensions. The bandpass layer is composed of a grided square loop and the switchable layer is integrated by coaxial hybrid square loops with an embedded bias network, whose configuration reduces the impact of bias lines on high-frequency transmission and, consequently, achieves polarization insensitivity. A prototype was fabricated and measured, which verified that the 3 dB transmission window covers 8.9–9.8 GHz, and the −10 dB wideband absorption covers 2.3–8.2 GHz. Good agreement is obtained between the numerical simulation and measurement results.

中文翻译：

---

具有可切换传输带的薄型基于 FSS 的偏振不敏感 Rasorber

在这封信中，提出了一种新的偏振不敏感、低剖面频率选择吸收器 (FSR)，它具有可切换的传输频带。该 FSR 由有损层、带通层和可切换层组成，其中安装了 pin 二极管并并联馈电。有损层由具有集总电阻器的紧凑分形元件组成，从而缩小了单元尺寸。带通层由网格方环组成，可切换层由同轴混合方环集成，嵌入偏置网络，其配置减少了偏置线对高频传输的影响，从而实现了极化不敏感。制造并测量了原型，验证了 3 dB 传输窗口覆盖 8.9-9.8 GHz，-10 dB 宽带吸收覆盖 2.3-8.2 GHz。