近年，自我注入鎖定雷達已經被證明對於微弱震動的訊號例如人體的心肺運動具有良好的靈敏度，同時能抑制靜止物體產生的靜態雜波干擾。然而先前的研究結果指出，受限於自我注入鎖定狀態下非線性失真的問題，傳統的自我注入鎖定雷達僅能在物體位移量小於λ/25時，也就是滿足小角度近似時偵測待測物的位移量。本論文首先提出一種正交自我注入鎖定雷達，使用一正交相移器調制注入訊號，並在後端使用兩階段的反正切解調獲得無失真的都普勒訊號。此外由於注入鎖定機制為一相位轉頻率調制的過程，待測物的位移量在注入鎖定狀態下會造成一頻寬不固定的頻率調制訊號，容易對其他無線系統造成電磁干擾。本論文接著提出可以穩定輸出頻率的頻率偏移式自我注入鎖定雷達，此架構透過兩個下混頻器與一個上混頻器將兩組獨立的自我注入鎖定路徑結合，適當地調整相移器以及衰減器可以分別控制注入訊號的相位以及頻率鎖定範圍，如此便可以達到頻率穩定的輸出訊號。此外，其低中頻的頻率解調器改善了諸多傳統延遲線頻率鑑別器的限制，與傳統架構相比有28 dB的訊雜比增益。本論文最後提出一種單次頻率轉換的自我注入鎖定雷達架構並討論在不同應用下效能的提升。當操作頻率降低時 (5.8 GHz到0.433 GHz)，電磁波在介質中有較佳的穿透性，故此架構可以利用將高頻段的自我注入鎖定振盪器降頻，使系統具有低的插入損耗同時保有高的頻率鎖定範圍，在透地和穿牆應用中具有良好的感測靈敏度。另一種是當操作頻率提升時 (2.4 GHz到5.8 GHz)，更高的中心頻率以及調制頻寬使頻率調制模式下的自我注入鎖定雷達有更好的距離解析度，當兩鄰近的物體距離大於距離解析度時，此架構的迴路相位差與頻譜峰值下的相位應保持一致，若物體間彼此的距離小於距離解析度，上述的相位判別則失效，故此架構可以用來判斷距離解析度發生的位置。而距離解析度的問題則可以透過本篇提出的頻率估計演算法來進一步提升至原先之40%–70%。本論文研究的實驗結果皆與理論預測吻合，驗證了相位和頻率偏移技術之先進自我注入鎖定雷達的性能。

The self-injection-locked (SIL) radar has been proved to be sensitive to tiny movement such as respiration and cardiopulmonary activities and good stationary clutter immunity. However, nonlinear distortion originated from the SIL phenomenon results in the difficulty detecting the motion which exceeds λ/25. In the first experiment, the quadrature SIL (QSIL) radar uses an additional phase shifter to repeatedly switch the phase delay of injection signals between quadrature interval, and a two-stage arctangent demodulation after frequency demodulation and coherent sampling are used to obtain a non-distortion Doppler signal. In addition, since the injection-locked mechanism is a phase-to-frequency modulation process, the displacement of the subject will cause a frequency modulation signal with an irregular bandwidth, which is likely to cause electromagnetic interference (EMI) to other wireless devices. The following presents a frequency-offset SIL (FOSIL) radar which combines two independents SIL path through two down-mixers and an up-mixer. By properly adjust the phase shifter and attenuator, the injection phase difference and locking range of the SIL oscillator (SILO) can be determined, respectively. Once combining these two SIL paths, a stabilized output signal can be achieved and resolve the EMI issue. Furthermore, the digital frequency demodulation at low-intermediate frequency (IF) end improves the shortcoming of the conventional delay discriminators. Last, this dissertation proposed single-conversion SIL (SCSIL) radar architectures and discussed the performance in different applications. The down-converted SCSIL radar outputs the low-frequency ISM band signal while having a high-frequency SILO with its better locking range. Therefore, this radar system achieves good sensitivity in through-wall detection or ground-penetrating applications. When the output frequency is increased from 2.4 to 5.8 GHz and operated in frequency-modulated continuous-wave mode by the frequency-converter unit. The frequency-phase relationship is used to determine the position of the range resolution issue happened, which can further alleviate the computation cost of the frequency estimation algorithm. The experimental results agree with the theoretical predictions, verifying the performance of the improved SIL radar using phase- and frequency-offset techniques.

論文審定書 i
摘要 iii
Abstract iv
List of Figures vii
List of Tables xi
Chapter 1Introduction1
1.1Research Motivation 1
1.2CW Radar for Noncontact Detection2
1.3SIL Radar System6
1.4Dissertation Overview8
Chapter 2Quadrature SIL Radar9
2.1Nonlinear Distortion of Conventional SIL Radar9
2.2Quadrature SIL Radar Front-End12
2.3Two-Stage Arctangent Demodulation14
2.3.1Measurement-Based DC Offset Calibration15
2.3.2Differential-Based DC Offset Calibration17
2.4Experimental Setup and Verification20
2.5Monitoring Vital Sign Using QSIL Radar28
2.6Comparison of Radar-Based Displacement Systems30
Chapter 3Frequency-Offset SIL Radar33
3.1Frequency-Offset SIL Radar Front-End33 
3.2Frequency Demodulation38
3.2.1Two Frequency Demodulator39
3.2.2Low-IF Architecture with Digital Frequency Demodulation40
3.3Experimental Setup and Verification45
3.3.1Single-Radar Experiment47
3.3.2Two-Radar Experiment51
3.4Comparison of SIL Radar for Vital Sign Detection55
Chapter 4Single-Conversion SIL Radar59
4.1System Architecture59
4.2Down-Converted SCSIL Radar61
4.2.1Problem Formulation61
4.2.2Detection Principle62
4.2.3Experimental Setup and Verification65
4.3Up-Converted SCSIL Radar67
4.3.1Detection Principle68
4.3.2Frequency Estimation Algorithm73
4.3.3Experimental Setup and Verification77
4.3.4Range and Doppler Signal Monitoring Using SCSIL Radar83
4.4Comparison of Radar-Based Range and Vital Sign Detection System89
Chapter 5Conclusions92
Bibliography95
Vita109

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