Frequency-modulated continuous wave (FMCW) radar systems in the millimeter and submillimeter range are technologically mature for many applicative fields such as automotive and aerospace industries for imaging and nondestructive testing. This work reports on a new implementation of a guided FMCW radar reflectometry unit for sensing and imaging applications. Only a terahertz dielectric waveguide is used for signal transmission between the transceiver module and the sample, thus drastically simplifying the experimental setup. Compared to continuous wave guided systems, one of the main advantages granted by the use of FMCW radars in combination with waveguides, is the differentiation capability between the reflected signals generated along the wave guide as parasitic signals or at its probing end as sensing information and therefore improving the expected signal-to-noise ratio. This innovative approach is demonstrated by using a dielectric hollow-core waveguide integrated with two different radar transceivers; the high-performance, III–V based 100 GHz SynView unit as a reference system and a compact, low-cost, printed circuit board (PCB)-integrated, 122 GHz transceiver developed by silicon-radar GmbH. Both three-dimensional electromagnetic simulations and raster scans are performed to investigate quantitatively the propagation behaviors including the coupling capabilities, dynamic range limitations, beam profile, and induced artefacts of the guided FMCW reflectometry system. The feasibility of a simplified guided terahertz FMCW reflectometry probing unit is proven. The integration of a solid immersion lens at the end of the waveguide is also demonstrated for imaging resolution improvement.

中文翻译：

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使用毫米波 FMCW 雷达的引导反射计成像单元

毫米和亚毫米范围内的调频连续波 (FMCW) 雷达系统技术成熟，适用于许多应用领域，例如汽车和航空航天工业的成像和无损检测。这项工作报告了用于传感和成像应用的制导 FMCW 雷达反射计单元的新实现。收发器模块和样品之间仅使用太赫兹介质波导进行信号传输，从而大大简化了实验设置。与连续波导系统相比，将 FMCW 雷达与波导结合使用的主要优势之一是，是沿波导作为寄生信号或在其探测端作为传感信息生成的反射信号之间的区分能力，因此提高了预期的信噪比。这种创新方法通过使用与两个不同雷达收发器集成的介电空芯波导来证明；高性能、基于 III-V 的 100 GHz SynView 单元作为参考系统和由 Silicon-radar GmbH 开发的紧凑、低成本、印刷电路板 (PCB) 集成的 122 GHz 收发器。执行三维电磁模拟和光栅扫描以定量研究传播行为，包括耦合能力、动态范围限制、光束轮廓和引导 FMCW 反射测量系统的感应伪影。证明了简化的制导太赫兹 FMCW 反射测量探测单元的可行性。还演示了在波导末端集成固体浸没透镜以提高成像分辨率。