A new method for detecting microwave harmonic Doppler signatures of held objects in cluttered environments is presented. Based on a passive harmonic tag combined with a pulsed microwave radar, the motion of tagged objects held by a person can be detected in high-clutter environments. In this letter, we present a new derivation of the dynamic harmonic signal response of a harmonic tag in motion. Based on a truncated Bessel function expansion, the model predicts the time-frequency signatures of sinusoidally moving objects with high accuracy. We present a pulsed harmonic radar transmitting at 2.51 GHz and receiving at 5.02 GHz, which is capable of measuring the harmonic micro-Doppler response of the tag with better signal-to-noise since the clutter response only exists at 2.51 GHz. The pulse waveform provides detection of the harmonic tag at larger distances than continuous-wave systems by increasing the peak power of the signal incident on the tag, while the average power is fixed with a low level. Measurements of a held tag at a distance of 1 m in a highly cluttered environment are presented, showing a strong match to the simulated results.

中文翻译：

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脉冲谐波多普勒雷达和无源RF标签，用于跟踪所持物体的动态运动

提出了一种在杂波环境下检测被摄物体微波谐波多普勒信号的新方法。基于无源谐波标签和脉冲微波雷达的结合，可以在高杂波环境中检测到人持有的带标签物体的运动。在这封信中，我们提出了运动中谐波标签的动态谐波信号响应的新推导。基于截断的贝塞尔函数展开，该模型可以高精度预测正弦运动对象的时频信号。我们提出了一种脉冲谐波雷达，其发射频率为2.51 GHz，接收频率为5.02 GHz，由于杂波响应仅存在于2.51 GHz，因此能够以更好的信噪比测量标签的谐波微多普勒响应。通过增加入射在标签上的信号的峰值功率，该脉冲波形可以在比连续波系统更大的距离处检测谐波标签，而平均功率则固定在一个较低的水平上。提出了在高度混乱的环境中距离1 m处的固定标签的测量结果，与模拟结果非常匹配。