total dc power consumption is 2.62 mW from 1.8 V supply voltage. Table 1 compares the summary performance of this work with other reported CMOS PLLs around 400 MHz. 4 | CONCLUSION A 224–448 MHz low-power fully integrated PLL has been implemented in standard 0.18-lm CMOS process. The dif- ferential ring-type oscillator is adopted for wide tuning rage and compact circuit size and TSPC divider is used to reduce the dc power consumption. A replica bias circuit is added to the input terminal of VCO to avoid the supply noise. The measurement results show that the phase noise is about 298 and 2115 dBc/Hz at 100 kHz and 10 MHz offset, respec- tively, with the center of 400 MHz. The total power con- sumption is 2.62 mW. The low-power fully integrated CMOS PLL is suitable for medical device applications. ACKNOWLEDGMENT The chips were fabricated by TSMC Semiconductors Corp. through the Chip Implementation Center (CIC), Taiwan. REFERENCES [1] Khalil W, Shashidharan S, Copani T, Chakraborty S, Kiaei S, Bakkaloglu B. A 700-uA 405-MHz all-digital fractional-N frequency-locked loop for ISM band applications. IEEE Trans Microwave Theory Techn. 2011;59:1319–1326. [2] Yan DL, Bin Z, Tamura A, Raja MK. “A 400MHz low power fractional-N synthesizer with GFSK GMSK modulation in 0.13lm CMOS. In: 14th International Symposium on Integrated Circuits (ISIC); December 2014;556–559. [3] Chen W-H, Loke W-F, Jung B. A 0.5-V, 440-lW frequency syn- thesizer for implantable medical devices. IEEE J Solid State Cir- cuits 2012;47:1896–1907. July [4] Italia A, Palmisano G. A 1.2-mW CMOS frequency synthesizer with fully-integrated LC VCO for 400-MHz medical implantable transceivers. In: IEEE Radio Frequency Integrated Circuits Sym- posium; June 2009;333–336. [5] Yang J, Skafidas E.“A low power MICS band phase-locked loop for high resolution retinal prosthesis. IEEE Trans Biomed Circuits Syst. 2013;7:513–525. July [6] Chen KH, Liao HS, Tzou LJ. A low-jitter and low power phase- locked loop design. In: The IEEE International Symposium on Geneva; May 2000;257–260. [7] Huang C-Y, Chao I-J, Wang H-Y. A phase-locked loop for receivers of UHF wireless microphone. In: IEEE 6th International Conference on ASIC; May 2000;423–426. [8] Zhu P, Gui P, Chen W, et al. A 400MHz-2.4GHz radiation-toler- ant self-biased phase-locked loop. In: 6th IEEE Dallas Circuits and Systems Workshop on System-on-Chip; November 2007;1–4. [9] Yuan J, Svensson C.High speed CMOS circuit technique. IEEE J. Solid-State Circuits 1989;24:62–70. How to cite this article: Tsai J-H, Lin C-L, Kuo Y-T. A 224-448 MHz low-power fully integrated phase- locked loop using 0.18-lm CMOS process. Microw Opt Technol Lett. 2017;59:1750–1755. https://doi.org/ 10.1002/mop.30620 Received: 7 December 2016 DOI: 10.1002/mop.30625 Design of 77 GHz half-shorted horn antenna with metamaterial lens Bin Huang 1,2 | Ling-yun Li 1 | Hao Sun 1 | Yun Sun 1 | Rui Tong 1 1 Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China 2 University of Chinese Academy of Sciences, Beijing 100049, China Correspondence Lingyun Li, Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China. Email: lilingyun@mail.sim.ac.cn Abstract In this article, we present new two-layer and light- weighted grid wire metamaterial lens implemented on the aperture of conical horn antenna to manufacture a small- sized and high-performance antenna applied in 77 GHz radar system. It could shorten half-length of horn antenna without deteriorating its gain, broadband, and matching performance. The metamaterial lens is made by thin cop- per sheet whose thickness is only 0.1 mm. The measured results show that the metamaterial lens enhances the gain about 3.4 dB (@77 GHz) than short ordinary antenna with the same physical dimension, which equals to double its length. The high-performance and small-sized bulk make it suitable for 77 GHz radar system. KEYWORDS 77 GHz radar system, high gain, horn antenna, metamaterial lens HUANG ET AL. | 1755