An 8-32 GHz Frequency Synthesizer based on a Wideband VCO Array with Bandwidth Extension Stage

This paper proposes a wideband signal source covering a bandwidth of two octaves from 8 GHz to 32 GHz. The system is based on an array of three wideband voltage controlled oscillators (VCOs) for octave wide frequency synthesis and a post-synthesis stage which extends the bandwidth by another octave. The circuits were fabricated in a 0.35micrometer SiGe bipolar technology with an ft/fmax = 170/250 GHz. The VCO tuning ranges are 28.9%, 26.2% and 24.7% respectively. The average output power was measured to be -3.5 dBm. The single-sideband phase noise at 1 MHz offset has an average value of -100 dBc/Hz over the entire bandwidth of two octaves. The system blocks VCO array, bandwidth extension and output buffer consume a power of 175 mW, 277mW and 150 mW.