MT2000: High‑Power (1 kW) Harmonic Load Pull For GaN Devices

Characterizing high-power GaN devices presents unique challenges that conventional load pull systems often struggle to overcome. As output power approaches the kilowatt level, achieving accurate harmonic impedance control while maintaining measurement integrity, safety, and repeatability becomes increasingly difficult. This application note explores how the Maury Microwave MT2000 addresses these limitations through a hybrid passive-active harmonic load pull architecture designed specifically for high-power RF amplifier development.

The note explains how the MT2000 combines passive pre-matching with controlled active impedance synthesis to minimize injected power while accurately reproducing high-VSWR load conditions. This hybrid approach overcomes the insertion loss limitations of passive systems and the excessive power demands of fully active load pull, enabling practical characterization of GaN devices operating at hundreds of watts to nearly 1 kW.

Readers will also learn how different harmonic tuning methods—including stub resonators, cascaded tuners, and multiplexer-based tuning—affect measurement accuracy. The MT2000 supports all three approaches while delivering high harmonic isolation that minimizes impedance errors and preserves calibration integrity. The application note also outlines the complete measurement workflow, from optimizing the fundamental load to automatically synthesizing precise high-VSWR target impedances.

Real-world measurement results demonstrate repeatable characterization of high-power GaN devices under extreme mismatch conditions, improving efficiency while supporting safe operation. The MT2000 enables engineers to accelerate power amplifier development with fast, accurate harmonic load pull measurements beyond the capabilities of traditional systems.