25 GHz inductorless VCO in a 45 GHz SiGe technology

This paper discusses the design and implementation of a 25 GHz VCO in a 45 GHz SiGe process. The VCO is based on a full-wave rectification frequency-doubling technique applied to a 13 GHz differential ring-type VCO. The VCO occupies an area of 150 /spl mu/m /spl times/ 150 /spl mu/m, consumes a dc power of 240 mW, exhibits a phase noise better than -87 dBc/Hz at 1 MHz offset and features a remarkably high ratio (25/45) of the VCO frequency to the process f/sub t/.