Modern aircraft is exposed to a variety of risks from electromagnetic environment (EME), and electromagnetic shielding is a useful method for protecting electronic equipment from the severe EME. In the meanwhile, aircraft employs more integrated modular avionics, whose enclosures are much smaller than conventional ones. Therefore, it is critical to invent new equipment for measuring the shielding effectiveness (SE) of small enclosures. This article proposes an integrated switching antenna composed of a square wave generator, switching circuit, impedance matching circuit, compact monopole, and battery. The SE of a tiny enclosure at several frequencies can be tested with an integrated switching antenna in a single test. Furthermore, the proposed construction does not require an external signal generator, which eliminates the need for any enclosure cuts for attaching a coaxial cable or soldering an antenna. To test the feasibility of the proposed antenna, a prototype is built to measure the SE of a tiny enclosure. The measurement shows a good agreement between the measured and simulated results. Furthermore, using the inverse fast Fourier transform, the time-domain SE may be determined from the frequency-domain measurements in the frequency range of 1 to 100 MHz. The calculated time-domain SE results could be useful for determining the amount of protection against lightning and high-altitude electromagnetic pulse.

中文翻译：

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用于 1 MHz 至 100 MHz 小型外壳屏蔽效能测试的集成开关天线设计

现代飞机面临电磁环境（EME）带来的各种风险，电磁屏蔽是保护电子设备免受严重EME影响的有效方法。与此同时，飞机采用了更加集成的模块化航空电子设备，其外壳比传统的小得多。因此，发明测量小型外壳屏蔽效能（SE）的新设备至关重要。本文提出了一种集成开关天线，由方波发生器、开关电路、阻抗匹配电路、紧凑单极子和电池组成。可以使用集成开关天线在一次测试中测试微型外壳在多个频率下的 SE。此外，所提出的结构不需要外部信号发生器，这消除了用于连接同轴电缆或焊接天线的任何外壳切口的需要。为了测试所提出的天线的可行性，我们构建了一个原型来测量微型外壳的 SE。测量结果表明测量结果与模拟结果非常吻合。此外，使用快速傅里叶逆变换，可以根据1至100MHz频率范围内的频域测量来确定时域SE。计算出的时域 SE 结果可用于确定针对雷电和高空电磁脉冲的防护量。