A general method based on harmonic balance techniques to simulate noise in free running oscillators

A novel approach using perturbation theory for simulating the noise behavior in free-running microwave oscillators based on a piecewise harmonic balance technique is outlined and applied to a planar integrated microwave oscillator at 14 GHz. A single-sideband phase noise of -90 dBc/Hz at an offset frequency of 100 kHz was measured. Simulated and measured single-sideband phase noise values agree within the accuracy of measurements. The method is limited neither to certain circuit topologies nor to certain noise sources. The proposed method has been demonstrated to be a fast, reliable, and numerically stable tool for the design of microwave oscillators.<>