A 1.5-V 3~10-GHz 0.18-µ m CMOS Frequency Synthesizer for MB-OFDM UWB Applications

An Ultra wide band (UWB) frequency synthesizer is designed and fabricated in 0.18-µm CMOS technology to generate all the carrier frequencies for 13 bands distributed from 3 to 10 GHz. It is composed of one phase-locked loop (PLL) and three single-side band (SSB) mixers. The polyphase filter is used to generate all needed quadrature signals in the circuit and band selectors are to select the frequency band. The sideband rejection can be over 30dB. The switching time between bands is around 3.75ns. The current consumption is 72mA under 1.5-V power supply. Index terms —MB-OFDM, UWB, frequency synthesizer, PLL, SSB mixer, polyphase filter.