A monolithic fast-hopping frequency synthesizer for MB-OFDM UWB

This paper presents a 3 GHz to 5 GHz monolithic fast-hopping frequency synthesizer designed in a 0.18 μm RF CMOS technology for multiband OFDM (MB-OFDM) ultra-wideband (UWB) application. This synthesizer provides 4 center frequencies. Each center frequency is generated by single-sideband (SSB) mixing of the output frequency from an on-chip phase-locked loop (PLL) and another frequency derived from the PLL. Band switching time of less than 2 ns is realized by using a multiplexer to switch the input signals of a SSB mixer. Operating at a 1.8 V supply, the LO leakage and unwanted sideband suppression for all the center frequencies are better than -40 dBc. Power dissipation is 65 mW and the chip area is 0.9 mm².