High efficiency microwave amplifier

Abstract

Disclosed is an apparatus and method for operating a microwave amplifier with improved efficiency and reduced harmonic emissions. The disclosed amplifier includes a variable rail voltage supply and a variable input drive stage. A controller continually monitors the amplifier output and adjusts the rail voltage and input drive signal to achieve high efficiency and low harmonic emissions. The amplifier may include a dynamic bias controller configured to operate the gain elements outside the linear region. Efficiencies of over 70% may be achieved by the disclosed amplifier.

Description

BACKGROUND[0001]1. Technical Field[0002]The present disclosure relates to systems and methods for providing energy to biological tissue and, more particularly, to improved apparatus and methods for amplifying microwave energy for use during surgical procedures.[0003]2. Background of Related Art[0004]Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryogenic, thermal, laser, etc.) are applied to tissue to achieve a desired result. Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, ablate, coagulate or seal tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the surgeon and applied to the tissue to b...

AI Technical Summary

Benefits of technology

The present patent provides an improved microwave ablation amplifier with a push-pull configuration that exhibits improved efficiency over a wide range of power output levels. The amplifier includes a gain stage, a rail voltage controller, and a drive controller. The amplifier control unit is operable to dynamically vary an operating parameter, such as the rail voltage and input level, to achieve stable operation of the generator over a range of output power levels. The control unit may also include a sensor to measure an operational parameter of the amplifier and adjust the operating parameter accordingly to achieve the desired output level. The technical effects of the present patent include improved efficiency, reduced harmonics, and reduced radiofrequency interference.

Problems solved by technology

Commonly used microwave power amplifiers are known to be inefficient.

The resulting heat becomes difficult to manage and may require the use of bulky and costly cooling systems, e.g., fans and heat sinks.

Additionally, the excess heat may cause thermal stress to other components of the generator, shortening generator life, decreasing reliability, and increasing maintenance costs.

Additionally, a class AB amplifier may exhibit crossover distortion that introduces undesirable harmonics into the surgical signal, which are known to cause radiofrequency interference in excess of acceptable limits.

Images