A consideration on numerical calculation of Q-factors in oscillation circuit based on formulation of S parameters

Even though Q-factors of oscillation circuits can be calculated by their input impedance, impedance matrices and frequency derivations, the numerical calculation accuracy may be degraded when the immittance locus drastically shifts for frequencies, in particular, the immittance rapidly changes from positive infinite to negative infinite. To improve the numerical calculation accuracy, the Q-factors of one- and two-ports oscillation circuits were formulated by using the scattering matrix having the values from 1 to -1. As the results of numerical calculation of Q factors in one- and two-port oscillation circuits, an advantage of the calculation procedure based on the scattering matrix was confirmed.