The fiber-optic extrinsic Fabry–Perot interferometer (EFPI) is one of the simplest sensing configurations and is widely used in various applications. Inspired by the EFPI, we report a novel and universal ultra-sensitive microwave sensing platform based on an open-ended hollow coaxial cable resonator. Two highly-reflective microwave reflectors were fabricated in a coaxial cable to form a microwave Fabry–Perot etalon. Although the operating wavelength of the proposed device is increased by five orders of magnitude compared to the fiber-optic EFPI (e.g., from 1500 nm to 150 mm), the resolution regarding the “pseudo cavity length” of the proposed device is as high as 0.6 nanometer, which is comparable to that of the EFPI. The resolution can be further increased by high-precision machining of the device. Due to its low cost, high sensitivity, all-metal structure, robustness, and ease of signal demodulation, it is envisioned that the proposed device will revolutionize the sensing field and enable many important sensing applications that take place in harsh environments.

中文翻译：

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受光纤外在法布里-珀罗干涉仪启发的微波器件：一种新型的超灵敏传感平台

光纤外部法布里-珀罗干涉仪 (EFPI) 是最简单的传感配置之一，广泛用于各种应用。受 EFPI 的启发，我们报告了一种基于开放式空心同轴电缆谐振器的新型通用超灵敏微波传感平台。在同轴电缆中制造两个高反射微波反射器，形成微波法布里-珀罗标准具。尽管与光纤 EFPI 相比，所提出器件的工作波长增加了五个数量级（例如，从 1500 nm 到 150 mm），但所提出器件的“伪腔长度”的分辨率高达0.6纳米，与EFPI相当。通过设备的高精度加工可以进一步提高分辨率。由于成本低、灵敏度高，