The letter highlights the importance of modelling the phase noise of an oscillator using the impulse
sensitivity function. A Colpitts oscillator in the common collector configuration is analyzed to obtain an expression
for its phase noise. The oscillator design is thus optimized for phase noise with respect to process and design
parameters. The fabricated voltage controlled oscillator at an oscillating frequency of 52.8 GHz has a measured
phase noise of -98.9 dBc/Hz at 1 MHz offset.