A multiple-frequency continuous-wave (MFCW) agile radar system has the ability to cope with various physiological conditions of a human subject. Following the mathematic model, a favorable carrier frequency for detection is pursued by analyzing the amplitude and composition of the baseband signal. In Experiment-1, a CMOS dual-band transceiver prototype emulate searching a subject from a distance. The frequencies of the dual-band system are 4.26–4.95 GHz and 17.06–19.79 GHz. During the experiment, the respiratory signal could be detected up to 12 m, and the heartbeat signal up to 6 m. Even with a wooden or a brick barrier in the path, the vital-sign detection remained satisfactory. Later, a concurrent MFCW detection is performed in Experiment-2 for more precise analyses. From the concurrent results, the breathing status can be inferred, and by cross-correlating the results after the ensemble empirical mode decomposition (EEMD) and principal component analysis (PCA), the nonlinear effects of respiratory harmonics or intermodulation tones are reduced, resulting in an accurate heart rate extraction. The receiver front-end and the signal source are manufactured using a 180-nm CMOS process, both packaged on an RO4003C printed-circuit board (PCB).

中文翻译：

---

用于各种胸部运动下生命体征检测的宽带 MFCW 敏捷雷达概念

多频连续波 (MFCW) 敏捷雷达系统具有应对人体各种生理状况的能力。依据数学模型，通过分析基带信号的幅度和成分，寻找有利的检测载频。在实验 1 中，CMOS 双频收发器原型模拟从远处搜索目标。双频系统的频率为 4.26-4.95 GHz 和 17.06-19.79 GHz。实验过程中，呼吸信号可检测到12 m，心跳信号可检测到6 m。即使路径上有木头或砖头屏障，生命体征检测仍然令人满意。稍后，在实验 2 中执行并发 MFCW 检测以进行更精确的分析。从并发结果可以推断出呼吸状态，通过对集成经验模态分解 (EEMD) 和主成分分析 (PCA) 后的结果进行互相关，减少了呼吸谐波或互调音调的非线性效应，从而实现了准确的心率提取。接收器前端和信号源采用 180-nm CMOS 工艺制造，均封装在 RO4003C 印刷电路板 (PCB) 上。