未來將是物聯網的世代，隨著獵能( Energy Harvester )技術之興起，應用產品相繼問世，透過無線傳能可以不經由任何導體，將電力能量從發電裝置傳送到接收裝置。而射頻無線傳能則利用無線電波本身具有能量的特性，將其收集轉為電力使用，因為無線電波與人類生活緊密共存，所以能隨時隨地充電，發射機與基地台等皆可以視作能量源，但是一般無線電波以 360° 傳送，因此缺乏指向性，導致轉換效率較低。
為了解決射頻無線傳能效率不佳的問題，過去本實驗室已經開發出一個具有波束成型技術之智慧型天線陣列的 915 MHz 功率發射器，天線陣列由四個貼片天線組成通過四個相移器的改變，將能量波束往不同的方向集中，提高傳遞能量的效率。由於獵能接收器配備於身上的手持智慧型設備及穿戴式感測裝置內部，因此需要開發一套能偵測移動式獵能接收器位置的方法，利用諧波雷達在偵測物體時會發射基頻訊號，而接收物體會反射回二次諧波的概念，所以在智慧型天線陣列中再加入一片接收反射回來之二次諧波的貼片天線，讓二次諧波 1830 MHz 能量可以轉換成直流訊號，以供微控制器做運算處理後，由結果去判別移動式獵能接收器的位置。因此二次諧波強弱反映了獵能接收器的動態位置，也代表了智慧型天線陣列的可傳輸能量範圍。
由於自由空間中的傳輸損耗，反射之二次諧波將會比基頻訊號減弱的更多，因此本論文提出一個自身具有二次諧波增強電路的獵能接收器，除了可供應能量給後級之射頻標籤，並能將射頻無線傳能之功率傳輸覆蓋範圍擴展的更廣泛，使得 915 MHz 之功率發射器具有更精確的方向檢測能力，完成一個具有能識別移動物件的位置且可以自動偵測之射頻無線傳能系統。
本論文獵能接收器之所有電路均使用台積電提供的TSMC 0.18um CMOS之製程實現，晶片規畫分為三部份：倍頻感測端電路、無線獵能端電路和應用通訊端電路。其中倍頻感測端電路為二次諧波之增強電路，由電感電容諧振器和開關元件所組成。無線獵能端電路包含了狄克森倍壓整流器和低壓降線性穩壓器，提供穩定之直流電壓給後級之射頻標籤使用。而應用通訊端電路為 ISM 頻帶之 2.44 GHz 低功率鎖相迴路( Phase-Locked Loop )，總耗能為 1.8 mW (量測用放大器不算在內)，因此獵能接收器輸入端只需 10 mW 以上，應用通訊端電路即開始運作。不論是倍壓整流器、低壓降線性穩壓器或是鎖相迴路，其所使用的電路均力求簡便，以降低電路的複雜度與能量消耗，提升各個子系統之轉換效率達到免維護和自行供電之效能。論文內容將依序於各個章節內詳細介紹子電路區塊，並展示量測結果，最後為結論與未來展望。

In this thesis, a second-order harmonic enhanced circuit design in energy harvester receiver is proposed for object location detection technique. The 915 MHz energy harvester is used to provide DC power for RF tag with a low power and low voltage phase-locked loop (PLL) and the circuits are fabricated by TSMC’s 180nm 1P6M CMOS process.
Wireless power transfer (WPT) via radio waves or magnetic fields coupling can deliver power to energy harvester receivers without any electrical contact. To solve the power conversion efficiency (PCE), adding a harmonic detection circuit into the energy harvester receiver design can improve the efficiency by the function of harmonic detection.
When the power emitter do the beam scan work and the energy harvester does not store enough DC energy, the second-order harmonic generated will be enhanced and reflected back to the power emitter. According to different reflected power levels of the second-order harmonic, the distance and the direction of the energy harvester receiver can be detected and estimated.
An enhanced second harmonic circuit which is composed of switch and a resonator is used. When the capacitor connected at the output of rectifier did not be charged enough, the switch will stay at the turn-on state. After sensing the DC level of the stored capacitor, the path will be opened and the harmonic enhancement will be halt.
The energy harvesting circuits include a Dickson voltage multiplier implemented by diodes with an energy storage capacitor, and a low dropout linear regulator that is used to provide clean DC power to the application circuits. The Dickson voltage multiplier can be simply constructed for RF power rectification.
At the same time, a low power 2.4 GHz phase lock loop in RF tag, which is powered by the above-mentioned harvester with input power of +10 dBm has been implemented too. The output power is -14 dBm. The spur level is -44.24 dBc and the phase noise is -109.7 dBc/Hz at 1 MHz frequency offset. By using a 1.2 V supply voltage, total power consumption without measurement buffers is 1.8348 mW.

[ 1 ] B. D. Van Veen, K. M. Buckley, "Beamforming: a versatile approach to spatial filtering," IEEE ASSP Magazine, vol. 5, pp. 4-24, 1988.
[ 2 ] J. C. Liberti, T. S. Rappaport, Smart Antennas for Wireless Communication Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall PTR 1999.
[ 3 ] J. H. Winters, "Smart antennas for wireless systems," IEEE Personal Commun, vol. 5, pp. 23-27, 1988.
[ 4 ] G. Tsoulos, M. Beach and J. McGeehan, " Wireless personal communication for the 21st century: European technological advances in adaptive antennas," IEEE Commun. Magazine, vol. 35, pp. 102-109, 1997.
[ 5 ] S.-F. Yang, T.-H. Huang, C.-C. Chen, C.-Y. Lu, and P.-J. Chung, " Beamforming power emitter design with 2x2 antenna array and phase control for microwave/RF-based energy harvesting," IEEE Wireless Power Transfer Conference (WPTC 2015), 2015, pp.1-4.
[ 6 ] Constantine A. Balanis, Antenna Theory: Analysis and Design, 3rd Edition, Wiley, 2005.
[ 7 ] Xiao Lu, Ping Wang, Dusit Niyato, Dong In Kim, and Zhu Han, " Wireless Networks with RF Energy Harvesting: A Contemporary Survey," IEEE Communications Surveys & Tutorials, vol.17, no. 2, Secondquarter 2015, pp. 757-789.
[ 8 ] 向敬成, 雷達系統, 五南, 2004.
[ 9 ] 陳俊丞, "應用諧波雷達之物件偵測電路," 碩士, 電機工程系碩士班, 國立成功大學, 台南市, 2016.
[ 10 ] C.-C. Chen, S.-F. Yang, T.-H. Huang, C.-Y. Lu, and P.J. Chung, "Chargeable object location identification technique for antenna-arrayed RF power emitter using microcontroller-based harmonic reflection detection circuit," Wireless Power Transfer Conference (WPTC 2016), 2016, pp.1-3.
[ 11 ] David K. Cheng, Field and Wave Electromagnetics, 2nd Edition, Addison-Wesley, 1989.
[ 12 ] S.-F. Yang, T.-H. Huang, "Design of Single-Turn Spiral Inductors With Embedding A Strong-Coupling LC Resonator for Interference Suppression," EEE Transactions on Electromagnetic Compatibility, vol. 59, no.3, Jun. 2017, pp. 919-926.
[ 13 ] C.-J. Peng, S.-F. Yang, A.-C. Huang, T.-H. Huang, F.-M. Wu, and P.-J. Chung, "Harmonic Enhanced Location Detection Technique for Energy Harvesting Receiver with Resonator Coupling Design," IEEE Wireless Power Transfer Conf. (WPTC 2017), Taipei, Taiwan, May 2017, pp.1-3.
[ 14 ] A. Shameli, A. Safarian, A. Rofougaran, M. Rofougaran, and F. De Flaviis, " Power harvester design for passive UHF RFID tag using a voltage boosting technique," IEEE Trans. Microw. Theory Tech, vol. 55, no. 6, pp. 1089–1097, Jun. 2007.
[ 15 ] Y. Yuan, S. Yin, and F. F. Dai, "A novel low-power input-independent MOS AC/DC charge pump," IEEE International Symposium on Circuits and Systems (ISCAS 2005), pp. 380-383, 2005.
[ 16 ] C.-H. Lee, K. McClellan, J. Choma, "A supply-noise-insensitive CMOS PLL with a voltage regulator using DC-DC capacitive converter," IEEE Journal of Solid-State Circuits, vol. 36, pp. 1453-1463, 2001.
[ 17 ] G.A. R incon-Mora, "Analog IC Design with Low-Dropout Regulators", McGraw-Hill, 2009.
[ 18 ] G.A. Rincon-Mora and P.E. Allen, "A Low-Voltage, Low Quiescent Current, Low Drop-Out Regulator," IEEE Journal of Solid-State Circuits, vol. 33, pp. 36-44, Jan. 1998.
[ 19 ] Sai Kit Lau, Ka Nang Leung, and P.K.T. Mok, "Analysis of low-dropout regulator topologies for low-voltage regulation," IEEE Conference on Electron Devices and Solid-State Circuits, pp. 1-4, Dec. 2003.
[ 20 ] V. Gupta, G.A. Rincon-Mora and P. Raha, "Analysis and design of monolithic, high PSR, linear regulators for SoC applications," IEEE International SOC Conference, pp.1-5, Sept. 2004.
[ 21 ] M. Nogawa, "LDO noise examined in detail," Texas Instruments Application Report, SLYT489, 2012.
[ 22 ] S.-H. Kim and S.-B. Cho, "Low phase noise and Fast locking PLL Frequency Synthesizer for a 915MHz ISM Band," IEEE International Symposium on Integrated Circuits Conference, p.p. 592–595, 2007.
[ 23 ] B. Razavi, “Design of Analog CMOS Integrated Circuit”, McGraw-Hill, 1996.
[ 24 ] 劉深淵, 楊清淵, “鎖相迴路,” 滄海書局,2006.
[ 25 ] Prof. K.-W. Cheng, Lecture Notes, Dept. of EE, NCKU.
[ 26 ] F. Gardner, "Charge-Pump Phase-Lock Loops," IEEE Transactions on Communications, vol. 28, pp. 1849-1858, 1980.
[ 27 ] Farid Golnaraghi, Benjamin C. Kuo, Automatic Control Systems, 9th Edition, Wiley, 2009.
[ 28 ] 鮑鵬宇, "應用於低電壓接收機系統之鎖相迴路設計," 碩士, 電機工程系碩士班, 國立成功大學, 台南市, 2015.
[ 29 ] 高曜煌, “射頻鎖相迴路IC設計”, 滄海書局, 2005.
[ 30 ] L. Bo, X. Shao, N. Shahshahan, N. Goldsman, T. Salter, and G.-M. Metze, " An Antenna Co-Design Dual Band RF Energy Harvester," IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 60, pp. 3256-3266, 2013.
[ 31 ] S. Scorcioni, L. Larcher, A. Bertacchini, L. Vincetti, and M. Maini, "An integrated RF energy harvester for UHF wireless powering applications," IEEE Wireless Power Transfer, Italy, pp.92-95, May 2013.
[ 32 ] G. Papotto, F. Carrara, and G. Palmisano, "A 90-nm CMOS Threshold-Compensated RF Energy Harvester," IEEE Journal of Solid-State Circuits, vol. 46, no. 9, pp. 1985-1997, June 2011.
[ 33 ] P. Hazucha, T. Karnik, B.-A. Bloechel, C. Parsons, D. Finan, and S. Borkar, "Area-Efficient Linear Regulator with Ultra-Fast Load Regulation," IEEE J. Solid-State Circuits, vol. 40, pp. 933-940, 2005.
[ 34 ] S. K. Lau, P. K. T. Mok, and K. N. Leung, "A Low-Dropout Regulator for SoC with Q-Reduction," IEEE Journal of Solid-State Circuits, vol. 42, pp. 658-664, 2007.
[ 35 ] T. Y. Man, K. N. Leung, C. Y. Leung, P. K. T. Mok, and M. Chan, "Development of Single-Transistor-Control LDO Based on Flipped Voltage Follower for SoC," IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 55, pp. 1392-1401, 2008.
[ 36 ] A. Swaminathan, K.-J. Wang and I. Galton, "A wide-bandwidth 2.4-GHz ISM band fractional-N PLL with adaptive phase noise cancellation," IEEE Journal of Solid-State Circuits, vol. 42, p.p. 2639-2650, 2007.
[ 37 ] K. Woo, Y. Liu, E. Nam and D. Ham, "Fast-lock hybrid PLL combining fractional-N and integer-N modes of differing bandwidths," IEEE Journal of Solid-State Circuits, vol. 43, pp. 379-389, 2008.
[ 38 ] B. Zhao, Y. Lian and H. Yang, "A low-power fast-settling bond-wire frequency synthesizer with a dynamic-bandwidth scheme," IEEE Transactions on Circuits and Systems, vol. 60, pp. 1188-1199, 2013.
[ 39 ] J. Shin and H. Shin, " A 1.9~3.8 GHz fractional-N PLL frequency synthesizer with fast auto-calibration of loop bandwidth and VCO frequency," IEEE Journal of Solid-State Circuits, vol. 47, pp. 665-675, 2012.
[ 40 ] D. H. Johnson, D. E. Dudgeon, Array Signal Processing: Concept and Techniques, Prentice Hall, 1993.
[ 41 ] John G. Proakis, Masoud Salehi, Communication Systems Engineering, 2nd Edition, Pearson, 2001.
[ 42 ] R. G. Cid-Fuentes, M. Y. Naderi, S. Basagni, K. R. Chowdhury, A. Cabellos-Aparicio and E. Alarc´on, "On signaling power: Communications over wireless energy," IEEE INFOCOM 2016 - The 35th Annual IEEE International Conference on Computer Communications, San Francisco, USA, April 2016, pp.1-9.