High efficiency amplifier and signal source module for ISM-band applications

The use of microwave technology is increasing in cardiac applications for microwave assisted balloon angioplasty and microwave cardiac ablation. Traditional microwave energy sources used in these procedures have poor efficiency and are large in size requiring them to be located far from the patient, and require coaxial cables to deliver power resulting in loss and heat generation causing potential safety issues. This paper presents the results of a simulation and measurement study for a high power/high efficiency amplifier and driver module for use in US or European ISM band medical and other applications. A high efficiency GaN-based Class E amplifier exhibited PAE greater than 70% at the 5.0 Watt output level, with power outputs greater than 10 Watts achievable with higher drain voltages. The integration of this amplifier with signal source and driver amplifier exhibited greater than 50% system efficiency in both ISM bands.