Detecting Critical Resonances in Microwave Amplifiers through Noise Simulations

TL;DR

This paper introduces a noise simulation-based method for detecting critical resonances in microwave amplifiers, simplifying the process by avoiding complex pole-zero analysis and additional circuit probes.

Contribution

It proposes a novel, less demanding approach using noise simulations to identify critical resonances, improving ease and efficiency for circuit designers.

Findings

Noise spectrum rise indicates low damping poles

Method successfully applied to two amplifier prototypes

Results align with traditional pole-zero analysis

Abstract

The presence of critical resonances in microwave power amplifiers has a negative impact on its behavior and performance. These critical resonances are usually predicted from pole-zero stability simulations. In this paper, a different and less demanding approach for the circuit designer is proposed. It is based on performing noise simulations of the amplifier and observing the rise in the noise spectrum that happens when the system has low damping poles. Critical resonance detection is simplified since no additional probes have to be inserted in the circuit and no post-processing for pole-zero analysis is required. The technique is applied to two amplifier prototypes fabricated in microstrip hybrid technology and the results are compared with the conventional pole-zero approach.