Dual Null Detection Points Removal and Time-Domain Sensitivity Analysis of a Self-Injection-Locked Radar for Small-Amplitude Motion Sensing
Dual Null Detection Points Removal and Time-Domain Sensitivity Analysis of a Self-Injection-Locked Radar for Small-Amplitude Motion Sensing
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DOI：
10.1109/tmtt.2022.3186299
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发表时间：
2022-09
影响因子：
4.3
通讯作者：
Dongyang Tang;Davi V. Q. Rodrigues;Michael C. Brown;Changzhi Li
中科院分区：
文献类型：
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作者：
Dongyang Tang;Davi V. Q. Rodrigues;Michael C. Brown;Changzhi Li
与目标位移导致相位调制的传统多普勒雷达相比，基于自注入锁定振荡器（筒仓）的雷达中的目标位移导致频率调制。由于瞬时相位是频率的时间积分，基于SILO的雷达被认为比常规多普勒雷达具有更高的灵敏度。然而，基于SILO的雷达和常规多普勒雷达之间的直接比较仍然需要定量地了解灵敏度的差异。本文提供了一个严格的时域分析的灵敏度的SILO为基础的雷达与基于延迟的频率解调器的小幅度周期运动。该分析遵循与常规多普勒雷达的时域分析类似的方法。结果表明，在基于SILO的雷达系统中，可能出现两种零检测点机制。目标距离可以引入一个零检测点，并且在频率解调器中添加的延迟可以引入另一个零检测点。此外，本文还提出了一种基于SILO的双零检测点消除雷达。与多普勒雷达不同，在多普勒雷达中，$I/Q$解调消除了由目标距离引入的零检测点，在基于SILO的雷达中，$I/Q$解调仅消除了由延迟电缆引入的零检测点。为了克服其他零检测点机制，在LNA之后引入移相器。实验进行了验证所提出的时域分析，并表明，这两种技术需要同时使用，以消除系统中的两个零检测点。灵敏度的比较是使用传统的多普勒雷达和基于SILO的雷达与相同的微波组件。
Compared with a conventional Doppler radar in which target displacement results in phase modulation, target displacement in a self-injection-locked oscillator (SILO)-based radar results in frequency modulation. Since the instantaneous phase is the time integral of frequency, the SILO-based radar is considered to have higher sensitivity than the conventional Doppler radar. However, a direct comparison between the SILO-based radar and the conventional Doppler radar is still needed to quantitatively understand the sensitivity difference. This article provides a rigorous time-domain analysis of the sensitivity of the SILO-based radar with a delay-based frequency demodulator for small-amplitude periodic motions. The analysis follows an approach similar to the time-domain analysis for the conventional Doppler radar. It reveals that two null detection point mechanisms could arise in SILO-based radar systems. The target distance may introduce one null detection point, and the delay added in the frequency demodulator may introduce another. Furthermore, this article also proposes an SILO-based radar with dual null detection points’ removal. Unlike the Doppler radar, where $I/Q$ demodulation eliminates the null detection point introduced by the target distance, $I/Q$ demodulation in the SILO-based radar only eliminates the null detection point introduced by the delay cable. To overcome the other null detection point mechanism, a phase shifter is introduced after the LNA. Experiments were carried out to validate the proposed time-domain analysis and demonstrate that both the techniques need to be used simultaneously to remove both null detection points in the system. The sensitivity comparison was performed using a conventional Doppler radar and an SILO-based radar built with identical microwave components.