Injection-Locked CMOS Frequency Doublers for μ-Wave and mm-Wave Applications

On-chip frequency generators for high frequency applications suffer from degradation of key passive components, variable capacitors in particular. In this framework, frequency multipliers can play a key role, allowing the design of voltage-controlled oscillators running at a frequency lower than required with advantage in terms of signal spectral purity and frequency tuning range. In this paper we present two injection locked frequency doublers for Ku-band and F-band applications respectively. Despite differences in implementation details, the same topology where a push-push pair injects a double frequency tone locking an autonomous differential oscillator is adopted. The circuits require limited input signal swing and provide a differential output over a broad frequency range. Dissipating 5.2 mW, the Ku-band multiplier, realized in a 0.13 μm CMOS node, displays an operation bandwidth from 11 GHz to 15 GHz with a peak voltage swing on each output of 470 mV. The F-band multiplier, realized in 65 nm CMOS technology, displays an operation bandwidth from 106 GHz to 128 GHz with a peak voltage swing on each output of 330 mV and a power dissipation of 6 mW. A prototype including the multiplier, driven by a half-frequency standard LC-tank VCO, demonstrates an outstanding 13.1% tuning range around 115 GHz.