本論文是使用環境中的Wi-Fi通訊波做為都卜勒雷達系統的發射訊號源，並結合IQ正交解調的接收機架構，去進行生理感測及人體成像的實驗。首先，針對雷達系統所使用的Wi-Fi通訊波做分析，由於其含有兩種正交的雜訊成分，分別為振幅調制(AM Noise)和相位調制雜訊(PM Noise)，會造成雷達系統的感測性能不佳，為了改善因Wi-Fi雜訊引起的問題，可經由本實驗室提出的注入鎖定技術以及本論文提出的雙通道雜訊抵消法去抑制此兩種Wi-Fi雜訊，使得都卜勒訊號品質提升，進而能夠量測到人體的呼吸和心跳。
接下來為了進一步實現人體成像，除了使用本論文提出的兩種方法進行直流準位偏移校正，還會基於數位波束成型相位天線理論提出一演算法，其原理是當目標物位於不同角度時，每個接收通道會收到不同相位差的訊號，可以利用此相位差來推得最大回波能量的反射角度，經過乘上一個角度權重後，即可獲得能量分布圖，並以1T4R的一維數位波束成型實驗驗證其可行性。最後透過分時多工(Time-Division Multiplexing, TDM)的技術將系統提升為8T8R的二維數位波束成像雷達，然後藉由數位訊號處理的技術抑制旁波辦(Sidelobe)進而實現本論文的最終目標－人體成像。
關鍵字:都卜勒雷達、數位波束成型、相位陣列、雷達成像、Wi-Fi雷達、生理監測、人體成像、分時多工

The aim of this thesis is to develop a passive Doppler radar based on a quadrature demodulation receiver architecture. The system uses a transmit signal of Wi-Fi and processes the echo signal of Wi-Fi to detect human vital signs and construct human images. At the beginning, two orthogonal Wi-Fi noise components, AM noise and PM noise, are analyzed because both noise components affect negatively on sensing performance of the system. To address this issue, this thesis proposes a dual-channel noise cancellation method for use in the afore-established injection-locking technique to reduce these two Wi-Fi noise components, and thereby improves the quality of Doppler signal to enable the detection of respiration and heart rates.
Next, to further construct human images, this thesis proposes two dc-offset calibration methods and a digital beamforming phased-array algorithm. The principle of digital beamforming is as follows: when the target is located at different azimuth angles, each receive channel receives an echo signal with different phases. The phase difference between receive channels can be used to derive the angle of maximum echo intensity. After applying an angular weight function, an energy distribution diagram can be obtained. Afterwards, this thesis conducts a 1T4R 1D digital beamforming experiment to verify the feasibility of the algorithm. Finally, this thesis uses the time-division multiplexing (TDM) technique to upgrade the system to an 8T8R 2D digital beamforming radar that can successfully construct human images after suppressing the sidelobes by digital signal processing.
Keywords: Doppler radar, digital beamforming, phased array, radar imaging, Wi-Fi radar, vital-sign monitoring, human imaging, time-division multiplexing.

論文審定書..................................................................................................................... i
論文公開授權書............................................................................................................ ii
誌謝.............................................................................................................................. iii
摘要............................................................................................................................... iv
Abstract .......................................................................................................................... v
目錄............................................................................................................................... vi
圖次............................................................................................................................... ix
表次.............................................................................................................................. xii
第一章 序論................................................................................................................ 1
1.1 研究背景與動機........................................................................................... 1
1.2 都卜勒雷達簡介與應用............................................................................... 2
1.3 二維波束成像簡介....................................................................................... 6
1.4 章節規劃....................................................................................................... 8
第二章 生理監測...................................................................................................... 10
2.1 前言............................................................................................................. 10
2.2 正交解調電路............................................................................................. 10
2.3 可行性評估實驗......................................................................................... 14
2.3.1 內部天線的增益問題與不同訊號源之比較.................................. 14
2.3.2 結論.................................................................................................. 17
2.4 應用於生理感測之開發............................................................................. 18
2.4.1 前言.................................................................................................. 18
2.4.2 雙通道雜訊抵消法與直流準位校正.............................................. 19
2.4.2.1 Wi-Fi訊號的分析與直流準位的校正 ................................ 19
2.4.2.2 雙通道雜訊抵消法的數學式與實驗步驟........................... 20
2.4.3 下行訊號源偵測模式...................................................................... 23
2.4.3.1 實驗系統設置....................................................................... 23
2.4.3.2 量測結果............................................................................... 26
2.4.4 上行訊號源偵測模式...................................................................... 27
2.4.4.1 實驗系統設置....................................................................... 27
2.4.4.2 利用上行訊號做訊號源之實驗結果................................... 30
2.4.5 上行訊號與下行訊號的比較.......................................................... 32
2.4.6 結合波束成型單人追蹤及生理徵象量測...................................... 33
2.4.6.1 實驗系統設置....................................................................... 33
2.4.6.2 量測結果............................................................................... 35
2.5 實驗討論..................................................................................................... 36
第三章 人體成像........................................................................................................ 37
3.1 前言............................................................................................................. 37
3.2 相位陣列簡介............................................................................................. 37
3.3 陣列天線設計............................................................................................. 40
3.4 訊號處理與校正程序................................................................................. 43
3.4.1 理論模型與模擬.............................................................................. 43
3.4.2 直流準位校正程序.......................................................................... 45
3.5 一維波束成型多人追蹤及生理感測......................................................... 48
3.5.1 實驗系統設置.................................................................................. 48
3.5.2 量測結果.......................................................................................... 51
3.6 二維波束成像及應用................................................................................. 54
3.6.1 一維波束成型到二維波束人體成像.............................................. 54
3.6.2 實驗系統設置.................................................................................. 55
3.6.3 雷達系統性能測量.......................................................................... 59
3.6.4 人體成像結果及應用...................................................................... 61
3.7 實驗討論與規格表..................................................................................... 62
第四章 結論.............................................................................................................. 63
參考文獻...................................................................................................................... 64

[1] 歐崇明、時文中、陳龍，人工智慧：現代方法，全華圖書，2011。
[2] L. D. Xu, W. He, and S. Li, ‘‘Internet of things in industries: A survey,’’ IEEE Trans. Ind. Informat., vol. 10, no. 4, pp. 2233-2243, Nov. 2014.
[3] M. W. Gifari, H. Zakaria and R. Mengko, “Design of ECG homecare:12-lead ECG acquisition using single channel ECG device developed on AD8232 analog front end,” in Proc. Int. Conf. Electr. Eng. Inform. (ICEEI), Aug. 2015, pp. 371-376.
[4] H. Rohling and E. Lissel, “77 GHz radar sensor for car application,” in Proc. IEEE Int. Radar Conf., May 1995, pp. 373-379.
[5] F. Adib, Z. Kabelac, and D. Katabi, “Multi-person localization via RF body reflections,” in Proc. USENIX NSDI, May 2015, pp. 279–292.
[6] Yole, “Reports radar for automotive is entering a new age,” Sep. 21, 2018. [Online]. Available: http://www.microwavejournal.com/articles/31079-yole-reports-radar-for-automotive-is-entering-a-new-age
[7] E. M. Nowara, T. K. Marks, H. Mansour and A. Veeraraghavan, “SparsePPG: Towards driver monitoring using camera-based vital signs estimation in near-infrared,” in Proc. IEEE CVPRW, Jun. 2018, pp. 1272-1281.
[8] M. V. Paulet, A. Salceanu and O. M. Neacsu, “Ultrasonic radar,” in Proc. Int. Conf. Expo. Elect. Power Eng. (EPE), Oct. 2016, pp. 551-554.
[9] P. C. Arthur, Hayes Ladson.,Introduction to Remote Sensing 2, Taylor and Francis, Lodon, 2007 [1991].
[10] C. Hatter, “第二次世界大戰中的雷達技術,” kknews. Jul. 13, 2018. [Online].
Available: https://kknews.cc/zh-tw/military/e3zxj6r.html
[11] H. Wang, “都卜勒效應簡介,” Dec. 25, 2001. [Online].
Available: http://www.phy.ntnu.edu.tw/oldjava/Doppler/index.html
[12] F. Strombeck, Z. S. He, and H. Zirath, “AMCW radar of micrometer accuracy distance measurement and monitoring,” in IEEE MTT-S Int. Microw. Symp. Dig., Jun. 2019, pp. 1473-1475.
[13] 黃泓偉，24 GHz 頻率調變連續波雷達系統之前端電路設計與整合， 國立交通大學電機學院通訊與網路科技產業研發碩士論文，2007。
[14] “Continuous-wave radar,” wiki. [Online].
Available: https://en.wikipedia.org/wiki/Continuous-wave_radar
[15] M. Jankiraman, FMCW radar design, Artech House, 2018.
[16] M. Jahn, R. Feger, C. Wagner, Z. Tong and A. Stelzer, “A four-channel 94-GHz SiGe-based digital beamforming FMCW Radar,” IEEE Trans. Microw. Theory Tech., vol. 60, no. 3, pp. 861-869, Mar. 2012.
[17] Matjaž Vidmar, “A radio altimeter for landing UAVs or small aircraft,” [Online].
Available: http://lea.hamradio.si/~s53mv/radalt/radalt.html
[18] “FMCW雷達測距/測速原理，及典型應用場景,” kknews. Jun. 22, 2018. [Online].
Available: https://kknews.cc/military/o3l3erm.html
[19] M. Poveda-García, A. Gómez-Alcaraz, A. Gil-Martínez, D. Cañete-Rebenaque, A. S. Martinez-Sala and J. L. Gómez-Tornero, “Frequency-scanned active monopulse radar based on bluetooth low energy devices using an array of two planar leaky-wave antennas,” in Proc. IEEE-APS Topical Conf. APWC, Sep. 2019, pp. 390-393.
[20] F. Barrau, B. Paille, E. Kussener and D. Goguenheim, “Distance measurement using narrowband ZigBee devices,” in Proc. Wireless Opt. Commun. Conf. (WOCC), May 2014, pp. 1-6.
[21] B. Tan, K. Woodbridge and K. Chetty, “A real-time high resolution passive Wi-Fi Doppler-radar and its applications,” in Proc. IEEE Radar Conf., Oct. 2014, pp. 1–6.
[22] F. Adib and D. Katabi, “See through walls with wifi!” in Proc. ACM SIGCOMM., Aug. 2013, pp. 75–86.
[23] F.-K. Wang, M.-C. Tang, Y.-C. Chiu and T.-S. Horng, “Gesture sensing using retransmitted wireless communication signals based on Doppler radar technology,” IEEE Trans. Microw. Theory Tech., vol. 63, no. 12, pp. 4592-4602, Dec. 2015.
[24] F. Daum, “Radar handbook, 3rd edition (M.I. Skolnik, Ed; 2008) [Book Review],” IEEE Aerosp. Elec. Sys. Mag., vol. 23, no. 5, pp. 41-41, May. 2008.
[25] “Bluetooth SIG更新藍牙技術規格,” TWCERT/CC. Jul. 24, 2018 [Online].
Available: https://www.twcert.org.tw/newepaper/cp-67-2520-62b6a-3.html
[26] “zigbee技術簡介,” ITW01. Nov. 27, 2018. [Online].
Available: https://itw01.com/Y5UF9EO.html
[27] 免費WI-FI 與簽下社區服務條款, Pixnet. Jul. 26, 2017. [Online]
Available: https://windrivernews.pixnet.net/blog/post/459717379
[28] “Beamforming,” wiki. [Online].
Available: https://en.wikipedia.org/wiki/Beamforming
[29] B. D. V. Veen and K. M. Buckley, “Beamforming: a versatile approach to spatial filtering,” IEEE ASSP Mag., vol. 5, no. 2, pp. 4-24, Apr. 1988.
[30] J. Butler and R. Lowe, Beam forming matrix simplifiers design of electrically scanned antennas, Electron. Design, 1961.
[31] J. S. Blogh, L. Hanzo, Third-Generation Systems and Intelligent Wireless Networking: Smart Antennas and Adaptive Modulation, Hoboken: John Willey & Sons, New Jersey, 2002.
[32] J. Joung, “Space–Time Line Code,” IEEE Access, vol. 6, pp. 1023-1041, Feb. 2018.
[33] J. Liang and Q. Liang, “Orthogonal Waveform Design and Performance Analysis in Radar Sensor Networks,” in Proc. MILCOM, Washington, DC, Oct. 2006, pp. 1-6.
[34] N. A. Shairi and T. A. Rahman, “Adjacent channel rejection analysis due to channel select filter in RF superheterodyne receiver of WLAN IEEE 802.11a,” in Proc. IEEE Conf. SCOReD, Pulau Pinang, Dec. 2012, pp. 140-143.
[35] W. Massagram, N. M. Hafner, B. Park, V. M. Lubecke, A. Host-Madsen and O. Boric-Lubecke, “Feasibility of heart rate variability measurement from quadrature Doppler radar using arctangent demodulation with DC offset compensation,” in Proc. 29th Ann. Int. Conf. IEEE Eng. Med. Bio. Soc., Sep. 2007, pp. 1643–1646.
[36] Analog Devices, Inc. [Online].
Available: https://www.analog.com/en/index.html
[37] Mini Circuits, Inc. [Online].
Available: https://www.minicircuits.com
[38] 周傳期，利用Wi-Fi訊號偵測手勢及深度學習辨識研究，國立中山大學電機工程學系碩士論文，2018。
[39] WI-FI-Link Technologies Co., Ltd. [Online].
Available: https://www.Wi-Fi-link.com.tw
[40] 蕭介勛，本地振盪源的注入鎖定與牽引現象研究，國立中山大學電機工程學系碩士論文，2008。
[41] 錢世樺，注入鎖定發射機研製與波束成型應用，國立中山大學電機工程學系碩士論文，2016。
[42] Marvelous Microwave, Inc. [Online].
Available: https://www.micro-mve.com/index.php
[43] National Instruments, Inc. [Online].
Available: https://www.ni.com/zh-tw.html
[44] L. Liu, Z. Liu, and B. E. Barrowes, ‘‘Through-wall bio-radiolocation with UWB impulse radar: Observation, simulation and signal extraction,’’ IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens., vol. 4, no. 4, pp. 791–798, Dec. 2011.
[45] A. S. Bugaev, I. A. Vasilyev, S. I. Ivashov, V. B. Parashin, I. K. Sergeev, A. P. Sheyko, and S. I. Schukin, “Remote control of heart and respiratory human system by radar,” Biomed. Tech. Radio-elec., no. 10, pp. 24–31, 2004.
[46] Z. G. Tegegne, C. Decroze, P. D. Bin, T. Fromenteze and C. Aupetit-Berthelemot, “Single channel microwave photonics digital beamforming radar imaging system,” J. Lightw. Technol., vol. 36, no. 3, pp. 675-681, Feb.1, 2018.
[47] X. Chen, W. Zhang, W. Rhee and Z. Wang, “A ΔΣ-TDC-based beamforming method for vital sign detection radar systems,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 61, no. 12, pp. 932–936, Dec. 2014.
[48] “Angular Resolution,” Radartutorial.eu. [Online].
Available: https://www.radartutorial.eu
[49] N. Mothe and P. D. Bin, “Multichannel microwave photonics signals summation device,” IEEE Photon. Technol. Lett., vol. 23, no. 3, pp. 140–142, Feb. 2011.
[50] X. Lan, M. Kintis, C. Hansen, W. Chan, G. Tseng and M. Tan, “A simple DC to 110 GHz MMIC true time delay line,” IEEE Microw. Wireless Compon. Lett., vol. 22, no. 7, pp. 369–371, Jul. 2012.
[51] Y. Liang, C. W. Domier and N. C. Luhmann, “MEMS based true time delay technology for phased antenna array systems,” in Proc. IEEE Asia-Pacific Micro. Conf., Bangkok, Dec. 2007, pp. 1-4.
[52] L. Jiang and H. Jafarkhani, “Multi-user analog beamforming in millimeter wave MIMO systems based on path angle information,” IEEE Trans. Wireless Commun., vol. 18, no. 1, pp. 608-619, Jan. 2019.
[53] S. Han, C. I, Z. Xu and C. Rowell, “Large-scale antenna systems with hybrid analog and digital beamforming for millimeter wave 5G,” IEEE Commun. Mag., vol.53, no.1, pp.186-194, Jan 2015.
[54] F. Adib, C.-Y. Hsu, H. Mao, D. Katabi, and F. Durand, “Capturing the human figure through a wall,” ACM Trans. Graph., vol. 34, no. 6, p. 219, 2015.
[55] Orfanidis S. J. “Electromagnetic Waves and Antennas(ch22.6, ch22.7),” 2002.
[56] Z. Peng and C. Li, “A portable K -band 3-D MIMO radar with nonuniformly spaced array for short-range Localization,” IEEE Trans. Microw. Theory Techn., vol. 66, no. 11, pp. 5075-5086, Nov. 2018.
[57] Stutzman W. L. and Thiele G. A., Antenna theory and design, Hoboken: John Willey & Sons, New Jersey, 2012.
[58] 黃昱齊，2.4 GHz數位波束成型都卜勒雷達之實現與生理監測應用，國立中山大學電機工程學系碩士論文，2019。
[59] Zeeshan, “Difference between uniform linear array (ULA) 3 dB beamwidth and bearing resolution” Stack Exchange Network. [Online].
Available: https://dsp.stackexchange.com/questions/39010/difference-between-uniform-linear-array-ula-3-db-beamwidth-and-bearing-resolut?
[60] UMCC, Inc. [Online]
Available: http://www.umcc111.com/SP8T-PhaseMatched.htm