Whitepaper

EMC Testing and Amplifier Selection

Published by Maury Microwave

This application note from Maury Microwave examines the role of amplifiers in electromagnetic compatibility testing, with a focus on immunity test setups. EMC testing encompasses both emission evaluation and immunity assessment, and generating the required field strengths for immunity tests demands careful amplifier selection. The paper reviews key selection criteria including frequency range, power output, linearity, gain stability, VSWR tolerance, and thermal management. It maps these requirements to specific standards across commercial (IEC 61000-4-3), military (MIL-STD-461), aerospace (DO-160), medical (IEC 60601), and automotive (ISO 11452) domains. The paper compares Class A and Class AB amplifier topologies, noting that modern Class AB designs offer a practical balance of efficiency and linearity for most EMC applications. Modern GaN-based solid-state power amplifiers are highlighted as superior replacements for older traveling wave tube technology, offering better gain stability and broader dynamic range.