A new Spice-oriented frequency-domain optimization technique

There are many kinds of optimization techniques for designing high-performance RF circuits. In this paper, we propose a new frequency-domain Spice-oriented optimization algorithm using the steepest descent method. We have developed a simulator executing the frequency-domain analysis based on the harmonic balance (HB) method, where all the nonlinear devices such bipolar transistors and MOSFETs are replaced by the equivalent HB modules. The objective functions in the optimization are estimated by the DC analysis of the modified HB circuits. On the other hand, our steepest descent algorithm is realized by equivalent circuit model. Thus, the optimum solution is stably found by the transient analysis of Spice. We show the formulation of HB circuits in section II, the Spice-oriented optimization algorithm in section III and the interesting examples in section IV