本研究在設計操作於 5.8 GHz 的胸戴式線性極化矩形環狀天線 (rectangular ring antenna, RRA)與基於 FR-4 的超穎表面，用於監測心率變異 (heart rate variability, HRV)。設計上納入具有方形環(square loop, SL)的方形裂環諧振器(square split-ring resonator, SSRR) 超穎表面來增強天線的指向性。通過偵測接近理想心臟運動之週期性擺動銅金屬板，證實由於超穎表面所增加的指向性增益會使偵測性能提高 77%。然後將其整合於調頻雙基自我注入鎖定(self-injection-locked, SIL)雷達系統中，其調制器與解調器在空間上相互分離，並成功偵測到人體的呼吸及心跳。在生命徵象偵測實驗中將使用SIL雷達測得的心跳時間間隔(interbeat interval, IBI)與使用心電圖(electrocardiogram, ECG)裝置測得之參考值進行比較，結果證明是有效及準確的，在整個實驗過程中，在不同受測者幾次測試中最大的百分比均方根誤差(percentage root mean square error, PRMSE)及平均絕對百分比誤差(mean absolute percentage error, MAPE)值分別為 6.26% 及 3.90%。本研究解決了降低天線結構整體面積及同時輻射高指向性電磁波並在靠近人體胸部時保持低反射係數的挑戰。

This research designs a chest-worn linearly polarized rectangular ring antenna (RRA) operating at 5.8 GHz and an FR-4-based metasurface for heart rate variability (HRV) monitoring. The inclusion of metasurface in the design enhances the directivity of the antenna by using a square split-ring resonator (SSRR) with a square loop (SL). The antenna structure was tested to detect a near-ideal cardiac movement using a periodically moving copper plate and confirmed a 77% improvement in performance due to the increased directive gain provided by the metasurface. It was then integrated into a frequency-modulated bistatic self-injection-locked (SIL) radar system where the modulator and demodulator are spatially separated from each other and successfully detected human respiration and heartbeat. The interbeat interval (IBI) of the vital sign detection experiment using the SIL radar was compared to its ECG reference and was proven to be effective and accurate having an average percentage root mean square error (PRMSE) and average mean absolute percentage error (MAPE) value of 6.26% and 3.90% throughout the experimentation with different subjects and several trials. The challenge of reducing the overall footprint of the antenna structure while simultaneously radiating highly directive electromagnetic waves and maintaining a low reflection coefficient when in proximity to a human chest is solved in this research.

論文審定書 ……………………………….…………………………………………… i
Acknowledgment ….…………………………………………………………………… ii
Abstract (Chinese) …………………………………….…………………….………… iii
Abstract (English) ………………………………………………...…………………… iv
Table of Contents …………………………………………….………………………… v
List of Figures ………………………………………….……………………………... vii
List of Tables ……………………………………………………….…….….…………. x
CHAPTER 1 – INTRODUCTION …………...….…………………………………… 1
1.1 Background ………………………………………………………………… 1
1.2 Objectives …………………………….……………………………….……. 3
1.3 Scope and Limitations ……………………………………………………… 4
1.4 Theoretical Framework …………………………...………………………… 5
CHAPTER 2 – REVIEW OF RELATED LITERATURE …...…………………… 10
2.1 Wearable Antennas ……………………………………………….……… 10
2.2 Wearable Antennas for Vital Sign Detection ……………………………… 13
CHAPTER 3 – METHODOLOGY ………………………………………………… 19
3.1 Design Process Synopsis ………………………………………….……… 19
3.2 Antenna Design ……………………………………...……………………. 21
3.3 Metasurface Design ………………………………….…………………… 26
3.4 Design Measurement ……………………………………………………… 29
3.5 The Moving Copper Plate Experimental Setup ……………………………. 31
3.6 The Vital Sign Detection Setup …………………….……………………… 34
CHAPTER 4 – RESULTS AND DISCUSSION …………………………………… 40
4.1 Scattering Parameter ………………….………………...…………………. 40
4.2 Antenna Radiation Pattern ………………………………………………… 48
4.3 Antenna Directive Gain …………………………………………………… 53
4.4 Metasurface Coefficients …………………….……………………………. 58
4.5 The Moving Copper Plate Experiment ……………………………………. 61
4.6 The Vital Sign Detection Experiment …………………...………………… 63
4.7 Comparison …………………………………………….………………… 77
CHAPTER 5 – CONCLUSION …………………………………….………………. 79
5.1 Recommendation ……………………………………….………………… 79
REFERENCES ………………………………………………………………………. 81

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