Efficient Calculation of Stabilization Parameters in RF Power Amplifiers

TL;DR

This paper introduces a novel, efficient method for calculating stabilization parameters in RF power amplifiers using linear control theory and harmonic transfer functions, improving stability analysis of large-signal regimes.

Contribution

It presents a new numerical approach for stabilization parameter calculation in RF amplifiers based on PLTV system analysis, enhancing stability design methods.

Findings

Successfully stabilizes a low-frequency oscillating amplifier

Stabilizes an unstable design with parametric oscillation

Demonstrates improved efficiency over conventional methods

Abstract

This paper proposes an efficient method for the calculation of the stabilization parameters in RF power amplifiers operating in periodic large-signal regimes. Stabilization is achieved by applying the principles of linear control theory for Periodic Linear Time-Varying (PLTV) systems. A numerical method is proposed to obtain the Harmonic Transfer Function that represents the system linearized around the large-signal steady state. Then, a feedback analysis is performed to calculate the closed-loop poles of the PLTV system. The proposed approach is demonstrated with two examples. Firstly, a three-stage amplifier that exhibits a low-frequency oscillation for increasing values of input power is correctly stabilized. Next, the stabilization of an unstable design that exhibits an odd-mode parametric oscillation is presented. The results of the proposed technique are compared to those obtained with the conventional parametric stability simulation. These examples serve to illustrate the capability and efficiency of the proposed approach.