Floquet-Based Stability Analysis of Power Amplifiers Including Distributed Elements

In this letter we present the first implementation of Floquet theory for the large-signal stability analysis of power amplifiers including transmission lines. We compare a few lumped-parameter and distributed designs of a combined class-B PA with equivalent in-band performance but different layouts. Distributed designs are shown to induce distinctive features from the stability standpoint, in particular with reference to the onset of odd-mode oscillations. These results show the potential and practical interest, also from the layout verification standpoint, of the extension of Floquet theory to the analysis of circuits including distributed elements.