A 6–9 GHz 5-band CMOS synthesizer for MB-OFDM UWB.doc

Vol. 31, No. 7 Journal of Semiconductors July 2010 A 6–9 GHz 5-band CMOS synthesizer for MB-OFDM UWB Chen Pufeng(陈普锋)? , Li Zhiqiang(李志强), Wang Xiaosong(王小松), Zhang Haiying(张海英), and Ye Tianchun(叶甜春) (Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China) Abstract: An ultra-wideband frequency synthesizer is designed to generate carrier frequencies for 5 bands distributed from 6 to 9 GHz with less than 3 ns switching time. It incorporates two phase-locked loops and one single-sideband (SSB) mixer. A 2-to-1 multiplexer with high linearity is proposed. A modified wideband SSB mixer, quadrature VCO, and layout techniques are also employed. The synthesizer is fabricated in a 0.18 m CMOS process and operates at 1.5–1.8 V while consuming 40 mA current. The measured phase noise is 128 dBc/Hz at 10 MHz offset, and the sideband rejection is 22 dBc at 7.656 GHz. Key words: 6–9-GHz; frequency synthesizer; PLL; MB-OFDM; UWB; CMOS DOI: 10.1088/1674-4926/31/7/075001EEACC: 2220 band CMOS I/Q frequency synthesizer based on a single SSB mixer architecture, which has the highest versatility and spec- tral purity with the realization of low complexity, low cost and low power consumption. The synthesizer uses two PLLs and generates 6600 MHz, 7128 MHz, 7656 MHz, 8184 MHz, 8712 MHz carriers with sufficient sideband rejection, and its switching time is less than 3 ns. With proper frequency plan- ning, only divide-by-2 dividers are needed in the feedback path of the PLL. Thus, more precise in-phase and quadrature phase sub-harmonics can be derived from the divider chain for SSB frequency mixing. 1. Introduction Ultra-wideband (UWB) technologies are mainly used to achieve short-range, high-data-rate wireless communications with less than 10 meters of transmission distance and higher than 480 Mb/s of transmission rate for wireless personal area networks (WPANs). Since 2002, the American Federal Communications Com- mission (FCC) app