A Low-Noise $K$-Band VCO Based on Room-Temperature Ferroelectric Varactors

This paper reports a K-band voltage-controlled oscillator based on room-temperature ferroelectric varactors. The circuit is realized as a hybrid module where flip-chip transistors are mounted on a silicon substrate with integrated ferroelectric varactors and passive circuitry. The size of the module is 4.7times2.2 mm
²
. The measured center frequency is 16.5 GHz with a linear tunability of 6.7% and an output power of 3 dBmplusmn1 dB over the tuning range. The measured phase noise at center frequency is -95 dBc/Hz at 100-kHz offset. Another version of the oscillator is measured operating at 19.6 GHz with a tunability of 3.3% and a phase noise of -102 dBc/Hz at 100-kHz offset