In order to protect the electronic equipment from high-power microwave (HPM), this article proposes an ultra-wideband strong field protection device, which is composed of a bandpass metasurface cascaded with an active metasurface. When the active metasurface is illuminated by low-power signals, its transmission passband overlaps with that of the bandpass metasurface. So working signals can pass through the protection device. However, when HPM is incident, the resonant frequency of the active metasurface moves to the stopband of bandpass metasurface. Therefore, both in-band and out-of-band HPM are reflected. The steady-state and transient-state characteristic of the device are analyzed. Results indicated that the insertion loss of the device is less than 1.5 dB over the range of 3.38–4.33 GHz (relative bandwidth reaches 24.6%). Also, it has the shielding effectiveness better than 13 dB for HPM in the range of 0–20 GHz.

中文翻译：

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基于超表面的超宽带强场保护装置

为了保护电子设备免受高功率微波（HPM）的影响，本文提出了一种超宽带强场保护装置，它由带通超表面和有源超表面级联而成。当有源超表面被低功率信号照射时，其传输通带与带通超表面的传输通带重叠。所以工作信号可以通过保护装置。然而，当 HPM 入射时，有源超表面的谐振频率移动到带通超表面的阻带。因此，带内和带外 HPM 都被反射。分析了器件的稳态和瞬态特性。结果表明，器件在 3.38-4.33 GHz 范围内的插入损耗小于 1.5 dB（相对带宽达到 24.6%）。还，