14.7 A 300GHz frequency synthesizer with 7.9% locking range in 90nm SiGe BiCMOS

The THz/sub-mm-Wave band is known to provide unique applications in spectroscopy, imaging and high-data-rate wireless communication. An accurate THz source is essential in coherent communications, radar systems, and frequency metrology. Recently, THz sources based on coupled VCOs with harmonic generation have been proposed [1]. However, open-loop signal sources exhibit severe frequency fluctuation, and are vulnerable to temperature/process/supply-induced frequency drift. The need for precise oscillation frequency with wide tuning range and low close-in phase noise calls for closed-loop topologies. Millimeter-Wave PLLs incorporating push-push VCOs have been demonstrated up to 164GHz [2] in silicon technology. [3] presented a 300GHz PLL with 0.12% locking range in III-IV technology.