“…This is particularly important when simulating bipolar VCOs at millimeter-wave frequencies, the transistor model must capture selfheating and avalanche multiplication, which are two positive feedback phenomena that cause significant nonconvergence problems at large voltage swings. During the transient simulations, the impedance of the Sparameter signal source is set to a small value (i.e., [10][11][12][13][14][15][16][17][18][19][20], to clearly reflect the expected effective resistance of the tank inductance at the oscillation frequency, and thus to allow for the onset of oscillations to occur.…”