Speaker
Description
High power RF transmission line supplied by Microwave Techniques LLC (MT), formerly MEGA Industries, can be found in nearly every high-power microwave application around the world. Through the acquisition of Ferrite Microwave Technologies (FMT), MT engineers have had the opportunity to focus on circulator technology and compensation methodology. It is well understood that the low loss ferrite material used in high-power circulators exhibit a strong temperature dependence, and active compensation is required for optimal system performance and amplifier protection. Traditional active compensation methodologies have involved monitoring and optimizing return loss or measuring coolant/circulator body temperature and adjusting magnetic bias on predetermined slopes.
This presentation discusses a new compensation methodology based on direct IR measurements of the ferrite temperature. Monitoring ferrite temperature using IR doesn’t suffer from thermal delays and doesn’t require active RF power to function allowing for a high degree of precision and speed even with quick changes or outages in RF power. Data logged results from an IR compensated ISM 100Kw circulator, tested under varying power levels and load impedances, are evaluated and compared to traditional compensation methodologies. Particular attention will be paid to transient conditions, phase, second to second changes, power ramping and the importance of data collection for optimizing circulator performance.
