與接觸式或者是穿戴式監測生理訊號的裝置相比，遠距離生理訊號監測裝置更受到關注，由於受測者不受連接線的限制以及電池使用時間的影響，生理訊號雷達漸漸受到大家喜愛，因為雷達訊號可以遠距非接觸偵測並能穿透障礙物。然而生理訊號雷達的技術瓶頸在於如何克服身體移動效應。當受測者移動他的身體，雷達偵測所輸出的訊號主要被身體移動效應所主宰，很難過濾出呼吸及心跳訊號。此外，假如能進一步偵測身體的活動及姿態，這樣在監測健康上將扮演更重要的角色。
本論文提出一自我鎖定及交互自我鎖定雷達去偵測身體移動下生物體的呼吸及心跳。為了降低身體移動效應，其中一雷達使用兩個壓控振盪器，各別自我注入鎖定以及交互注入鎖定，並使用兩個不同增益的天線，而能抵銷大部分的身體移動訊號，並保留生理訊號。另一雷達是基於自我注入鎖定技術並利用在受測者前後的兩支天線去發射以及重新發射一連續波至身體的前後兩側，而能克服大擺幅身體移動效應進行即時生理訊號偵測。
本論文最後提出一單脈衝生理訊號雷達，其結合連續波及自我注入鎖定技術而具有高靈敏度去偵測與定位人體上之生理訊號。此雷達利用連續波和場型及自我注入鎖定差場型來接收與處理回波訊號，因此能產出單脈衝比例來決定回波訊號的到達方向，藉此測得人體上之生理訊號的垂直位置做為姿勢分類用途。此外，此雷達可偵測跌倒過程中身體姿勢的變化做為跌倒警報用途。

Compared to the contact or wearable devices to monitor vital signs, remote detection devices attract more attention because the subject to be monitored is not confined to the limitations of wire connections or battery life. Therefore, the radar for monitoring vital signs becomes more and more popular because it is remote, contactless and it penetrates obstacles. However, the bottleneck of the radar technique is how to overcome the random body movement effect. When the subject moves his body, the radar detection output is dominated by the body movement signal and it is difficult to identify the respiration and heartbeat frequencies in the output spectrum. Apart from this, if the radar can further detect body motion and posture, it can monitor health more effectively in our daily life.
This dissertation presents two vital-sign radars for monitoring vital signs of a human subject with random body movements. To detect vital signs with reduced body motion artifacts, one radar uses two voltage-controlled oscillators that are self-injection locked (SIL) to themselves and mutually injection locked to each other. Additionally, it uses two different gain antennas. Consequently, this radar cancels out most of the body motion artifacts while preserving the vital sign signals. The other radar is based on SIL technology with two antennas to transmit and retransmit a continuous wave to opposite sides of a human body for real-time monitoring vital signs with large body movements.
This dissertation finally presents a monopulse radar that combines continuous-wave (CW) and SIL technologies with high sensitivity to detect and localize vital signs of a human subject. The radar utilizes a CW sum pattern and an SIL difference pattern to receive and process the echo signal from the subject, so it can produce a monopulse ratio to determine the direction of arrival of the echo signal. With this capability, this radar can measure the vertical position of the subject’s vital signs for posture classification purpose. Moreover, this radar can be used for a fall alarm by detecting the change of posture during a fall.

Contents


1 Introduction 1
1.1 Research Motivation 1
1.2 Random Body Movement Cancellation 2
1.3 Posture and Fall Detection 3
1.4 Dissertation Overview 4
2 An SMIL Radar with RBMC 6
2.1 SMIL Radar 6
2.1.1 System Architecture 7
2.1.2 Antenna Setup 9
2.1.3 System Model 10
2.2 Experiment on Actuator-Controlled Movement 13
2.2.1 Experimental Setup 13
2.2.2 Comparison of Results 19
2.3 Monitoring Vital Signs with Random Body Movements 23
3 T&RT SIL Radar for Large RBMC 28
3.1 T&RT SIL Radar 28
3.1.1 System Architecture and Model 29
3.1.2 Clutter Echoes 32
3.2 Calibration Method 34
3.2.1 Calibration Setup 34
3.2.2 Calibration Procedure 36
3.3 Monitoring Vital Signs with Large Body Movements 42

4 Hybrid Continuous-Wave and Self-Injection-Locking Monopulse Radar 49
4.1 Hybrid CW and SIL Monopulse Radar 49
4.1.1 System Architecture 51
4.1.2 System Model 52
4.1.3 Calibration Procedure 55
4.2 Posture and Fall Detection 57
4.2.1 Posture Detection 57
4.2.2 Fall Detection 60
5 Conclusions 64
Bibliography 65
Vita 71

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