{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:42:47Z","timestamp":1760197367316,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,4,1]],"date-time":"2018-04-01T00:00:00Z","timestamp":1522540800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Recently, studies have been actively carried out to implement motion detecting sensors by applying radar techniques. Doppler radar or frequency-modulated continuous wave (FMCW) radar are mainly used, but each type has drawbacks. In Doppler radar, no signal is detected when the movement is stopped. Also, FMCW radar cannot function when the detection object is near the sensor. Therefore, by implementing a single continuous wave (CW) radar for operating in dual-mode, the disadvantages in each mode can be compensated for. In this paper, a dual mode local oscillator (LO) is proposed that makes a CW radar operate as a Doppler or FMCW radar. To make the dual-mode LO, a method that controls the division ratio of the phase locked loop (PLL) is used. To support both radar mode easily, the proposed LO is implemented by adding a frequency sweep generator (FSG) block to a fractional-N PLL. The operation mode of the LO is determined by according to whether this block is operating or not. Since most radar sensors are used in conjunction with microcontroller units (MCUs), the proposed architecture is capable of dual-mode operation by changing only the input control code. In addition, all components such as VCO, LDO, and loop filter are integrated into the chip, so complexity and interface issues can be solved when implementing radar sensors. Thus, the proposed dual-mode LO is suitable as a radar sensor.<\/jats:p>","DOI":"10.3390\/s18041057","type":"journal-article","created":{"date-parts":[[2018,4,2]],"date-time":"2018-04-02T12:32:20Z","timestamp":1522672340000},"page":"1057","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Design of Dual-Mode Local Oscillators Using CMOS Technology for Motion Detection Sensors"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2612-0337","authenticated-orcid":false,"given":"Keum-Won","family":"Ha","sequence":"first","affiliation":[{"name":"Microwave Embedded Circuit &amp; System (MECAS) Lab., School of Electrical Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjack-gu, Seoul 06974, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeong-Yun","family":"Lee","sequence":"additional","affiliation":[{"name":"Microwave Embedded Circuit &amp; System (MECAS) Lab., School of Electrical Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjack-gu, Seoul 06974, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeong-Geun","family":"Kim","sequence":"additional","affiliation":[{"name":"Integrated Radar Lab., Department of Electronic Engineering, KwangWoon University, 20 Gwangun-ro, Nowon-gu, Seoul 01897, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0675-1115","authenticated-orcid":false,"given":"Donghyun","family":"Baek","sequence":"additional","affiliation":[{"name":"Microwave Embedded Circuit &amp; System (MECAS) Lab., School of Electrical Engineering, Chung-Ang University, 84 Heukseok-ro, Dongjack-gu, Seoul 06974, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,4,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1905","DOI":"10.1109\/JSSC.2014.2315650","article-title":"An X-Band Radar Transceiver MMIC with Bandwidth Reduction in 0.13 \u00b5m SiGe Technology","volume":"49","author":"Yu","year":"2014","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1109\/TMTT.2015.2504977","article-title":"A Fully Integrated X-Band Phased-Array Transceiver in 0.13 \u00b5m SiGe BiCMOS Technology","volume":"64","author":"Liu","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1109\/TMTT.2016.2520469","article-title":"A SiGe Fractional-N Frequency Synthesizer for mm-Wave Wideband FMCW Radar Transceivers","volume":"64","author":"Hasenaecker","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1109\/LMWC.2016.2574829","article-title":"A Low-Phase-Noise 77-GHz FMCW Radar Transmitter with a 12.8-GHz PLL and a x6 Frequency Multiplier","volume":"26","author":"Song","year":"2016","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1109\/TMTT.2016.2629476","article-title":"Single-Antenna FMCW Radar CMOS Transceiver IC","volume":"65","author":"Pyo","year":"2017","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1109\/TMTT.2012.2184136","article-title":"A 24-GHz CMOS UWB Radar Transmitter with Compressed Pulses","volume":"60","author":"Yang","year":"2012","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_7","first-page":"859","article-title":"A 79-GHz Adaptive-Gain and Low-Noise UWB Radar Receiver Front-End in 65-nm CMOS","volume":"64","author":"Jang","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"928","DOI":"10.1109\/JSSC.2010.2040234","article-title":"A 77 GHz 90 nm CMOS Transceiver for FMCW Radar Applications","volume":"45","author":"Mitomo","year":"2010","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1399","DOI":"10.1109\/TMTT.2015.2406071","article-title":"76\u201381-GHz CMOS Transmitter with a Phase-Locked-Loop-Based Multichirp Modulator for Automotive Rradar","volume":"63","author":"Park","year":"2015","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1109\/TMTT.2008.2008942","article-title":"Design of X-band RF CMOS Transceiver for FMCW Monopulse Radar","volume":"57","author":"Wang","year":"2009","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Yeo, H., Ryu, S., Lee, Y., Son, S., and Kim, J. (February, January 31). 13.1 A 940MHz-Bandwidth 28.8 \u00b5s-Period 8.9 GHz Chirp Frequency Synthesizer PLL in 65nm CMOS for X-band FMCW Radar Applications. Proceedings of the 2016 IEEE International Solid-State Circuits Conference (ISSCC), San Francisco, CA, USA.","DOI":"10.1109\/ISSCC.2016.7417995"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"234","DOI":"10.5515\/JKIEES.2012.12.4.234","article-title":"A Compact Ka-Band Doppler Radar Sensor for Remote Human Vital Signal Detection","volume":"10","author":"Han","year":"2012","journal-title":"J. Electromagn. Eng. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2309","DOI":"10.3390\/s150202309","article-title":"Preliminary Study of a Millimeter Wave FMCW InSAR for UAS Indoor Navigation","volume":"15","author":"Scannapieco","year":"2015","journal-title":"Sensors"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Baselice, F., Ferraioli, G., Lukin, S., Matuozzo, G., Pascazio, V., and Schirinzi, G. (2016). A New Methodology for 3D Target Detection in Automotive Radar Applications. Sensors, 16.","DOI":"10.3390\/s16050614"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2812","DOI":"10.1109\/TMTT.2014.2358572","article-title":"A Hybrid FMCW-Interferometry Radar for Indoor Precise Positioning and Versatile Life Activity Monitoring","volume":"62","author":"Wang","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Liang, F., Qi, F., An, Q., Lv, H., Chen, F., Li, Z., and Wang, J. (2016). Detection of Multiple Stationary Humans Using UWB MIMO Radar. Sensors, 16.","DOI":"10.3390\/s16111922"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Yue, W., Zhang, Y., Liu, Y., and Xie, J. (2016). Radar Constant-Modulus Waveform Design with Prior Information of the Extended Target and Clutter. Sensors, 16.","DOI":"10.3390\/s16060889"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1334","DOI":"10.1109\/TMTT.2016.2633352","article-title":"A Portable FMCW Interferometry Radar With Programmable Low-IF Architecture for Localization, ISAR Image, and Vital Sign Tracking","volume":"65","author":"Peng","year":"2017","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"14661","DOI":"10.3390\/s150614661","article-title":"Radar Sensing for Intelligent Vehicles in Urban Environments","volume":"15","author":"Reina","year":"2015","journal-title":"Sensors"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1109\/TMTT.2013.2291541","article-title":"Wireless cooperative synchronization of coherent UWB MIMO radar","volume":"62","author":"Kong","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1049\/ecej:19900043","article-title":"New ideas in FM radar","volume":"2","author":"Griffiths","year":"1990","journal-title":"Electron. Commun. Eng. J."},{"key":"ref_22","unstructured":"Skolnik, M. (1970). Radar Handbook, McGraw-Hill Inc.. [3rd ed.]."},{"key":"ref_23","unstructured":"Federal Communications Commission Office of Engineering and Technology Policy and Rules Division (2017). FCC Online Table of Frequency Allocations, Revised on 13 December 2017."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1109\/LMWC.2007.895732","article-title":"High-Speed FMCW Radar Frequency Synthesizer with DDS Based Linearization","volume":"17","author":"Scheiblhofer","year":"2007","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_25","unstructured":"Im, Y.T., Lee, J.H., and Park, S.O. (2011, January 24\u201325). A DDS and PLL-based X-band FMCW Radar System. Proceedings of the 2011 IEEE MTT-S International Microwave Workshop Series on Intelligent Radio for Future Personal Terminals, Daejeon, South Korea."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Jahagirdar, D.R. (2012, January 7\u201311). A High Dynamic Range Miniature DDS-based FMCW Radar. Proceedings of the 2012 IEEE Radar Conference, Atlanta, GA, USA.","DOI":"10.1109\/RADAR.2012.6212259"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1447","DOI":"10.1109\/TEMC.2015.2442618","article-title":"A Spread Spectrum Clock Generator Using a Programmable Linear Frequency Modulator for Multipurpose Electronic Devices","volume":"57","author":"Ryu","year":"2015","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Lee, S., Kim, D., and Jeon, L. (September, January 30). A CMOS X-band FMCW generator IC for Radar Applications. Proceedings of the 2017 IEEE International Symposium on Radio-Frequency Integration Technology (RFIT), Seoul, Korea.","DOI":"10.1109\/RFIT.2017.8048226"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Ha, K.W., Lee, J.Y., Park, S., and Baek, D. (September, January 30). A Dual-mode Signal Generator using PLL for X-band Radar Sensor Applications. Proceedings of the 2017 IEEE International Symposium Radio-Frequency Integration Technology (RFIT), Seoul, Korea.","DOI":"10.1109\/RFIT.2017.8048271"},{"key":"ref_30","unstructured":"Piper, S. (1991, January 12\u201313). FMCW Linearization Bandwidth Requirements. Proceedings of the 1991 IEEE National Radar Conference."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Frischen, A., Hasch, J., and Waldschmidt, C. (2015, January 9\u201311). FMCW Ramp Non-Linearity Effects and Measurement Technique for Cooperative Radar. Proceedings of the 2015 European Radar Conference (EuRAD), Paris, France.","DOI":"10.1109\/EuRAD.2015.7346349"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Wu, L., Peng, S.S., and Shi, X.Q. (2008, January 21\u201324). Effects of Transmitter Phase Noise on Millimeter Wave LFMCW Radar Performance. Proceedings of the 2008 International Conference on Microwave and Millimeter Wave Technology, Nanjing, China.","DOI":"10.1109\/ICMMT.2008.4540709"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Thurn, K., Ebelt, R., and Vossiek, M. (2013, January 2\u20137). Noise in Homodyne FMCW Radar Systems and its Effects on Ranging Precision. Proceedings of the 2013 IEEE MTT-S International Microwave Symposium Digest, Seattle, WA, USA.","DOI":"10.1109\/MWSYM.2013.6697654"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Dhar, D., van Zeijl, P.T.M., Milosevic, D., Gao, H., and van Roermund, A.H.M. (2017, January 28\u201331). Modeling and Analysis of the Effects of PLL Phase Noise on FMCW Radar Performance. Proceedings of the 2017 IEEE International Symposium on Circuits and Systems (ISCAS), Baltimore, MD, USA.","DOI":"10.1109\/ISCAS.2017.8050525"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Huang, L., Chen, H., and Bai, J. (2016, January 16\u201318). Simulation of the Effect of Signal Source\u2019s Phase Noise on Millimeter Wave Automotive Radar System Based on SystemVue. Proceedings of the 2016 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, Nanjing, China.","DOI":"10.1109\/iWEM.2016.7505069"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"724","DOI":"10.1109\/JSSC.2012.2230542","article-title":"A Push\u2013Pull Class-C CMOS VCO","volume":"48","author":"Mazzanti","year":"2013","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1109\/JSSC.2012.2227603","article-title":"Class-C VCO with Amplitude Feedback Loop for Robust Start-Up and Enhanced Oscillation swing","volume":"48","author":"Deng","year":"2013","journal-title":"IEEE J. Solid-State Circuits"},{"key":"ref_38","unstructured":"Yun, S.-J., Shin, S.-B., Choi, H.-C., and Lee, S.-G. (2005, January 10). A 1 mW Current-Reuse CMOS Differential LC-VCO with Low Phase Noise. Proceedings of the ISSCC. 2005 IEEE International Digest of Technical Papers. Solid-State Circuits Conference, San Francisco, CA, USA."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1109\/LMWC.2014.2313582","article-title":"Gm-Boosted Complementary Current-Reuse Colpitts VCO with Low Power and Low Phase Noise","volume":"24","author":"Ha","year":"2014","journal-title":"IEEE Microw. Wirel. Compon. Lett."},{"key":"ref_40","first-page":"676","article-title":"Transformer-Based Current-Reuse Armstrong and Armstrong\u2013Colpitts VCOs","volume":"61","author":"Ha","year":"2014","journal-title":"IEEE Trans. Circuits Syst. II Express Briefs"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Pavan, S., Schreier, R., and Temes, G.C. (2005). Understanding Delta-Sigma Data Converters, John Wiley & Sons Inc.","DOI":"10.1109\/9780470546772"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/1057\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:59:18Z","timestamp":1760194758000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/1057"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,4,1]]},"references-count":41,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2018,4]]}},"alternative-id":["s18041057"],"URL":"https:\/\/doi.org\/10.3390\/s18041057","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2018,4,1]]}}}