Parallel Microwave Pulse Amplifier for Faster Electrosurgery
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Solution Overview
Problem
Existing electrosurgical generators face challenges in delivering high power microwave frequency pulses efficiently for tissue coagulation or ablation, leading to prolonged treatment times and unwanted thermal effects due to energy distribution and perfusion issues.
Innovation Solution
An amplifier line-up comprising a microwave signal generator, modulator, and an array of amplifiers connected in parallel, which produces high power microwave pulses with short duration and adjustable duty cycle, minimizing thermal losses and allowing for precise energy delivery through smaller coaxial cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If continuous wave signal is delivered at low power (e.g., 20 W for 100 s), then the total energy payload (2 kJ) is delivered, but the treatment time is prolonged and thermal effects from perfusion increase
Solution Approach 1:
The patent applies periodic pulsed action by delivering microwave energy in short high-power pulses (e.g., 2 kW) rather than continuous low-power signal. The pulses are designed with durations equal to or less than the body's thermal reaction time (e.g., 10 s or less), creating periodic energy delivery that achieves the same 2 kJ payload in shorter time while minimizing thermal losses through perfusion.
2Productivity
If high power pulses are delivered, then treatment time is reduced and thermal losses are minimized, but the amplifier system complexity increases
Solution Approach 1:
The patent segments the amplifier system into multiple parallel amplifier modules (e.g., 8 amplifiers) that can be independently controlled. Each amplifier handles a portion of the total power requirement, allowing the system to deliver high peak power (e.g., 2 kW) in pulses while managing complexity through modular architecture. The parallel configuration enables efficient pulse delivery without requiring a single overly complex high-power amplifier.
3Object-affected harmful factors
If continuous energy delivery is used, then the energy payload is delivered, but patient discomfort increases and thermal compensation mechanisms are activated
Solution Approach 1:
The patent uses periodic pulsed energy delivery where the pulse duration is specifically chosen to be equal to or less than the body's thermal reaction time (e.g., 10 s or less). This timing strategy delivers the required energy payload before the body's natural thermal compensation mechanisms (such as increased blood flow) can activate, thereby reducing patient discomfort while maintaining effective treatment.
4Length of moving object
If smaller diameter coaxial cables are used, then the apparatus can be more compact and easier to insert, but thermal effects in the cable increase with continuous power delivery
Solution Approach 1:
The patent applies periodic pulsed power delivery to smaller diameter coaxial cables, where the pulse duration is shorter than the cable's thermal response time. This allows the cable to dissipate heat between pulses, preventing excessive temperature buildup despite the smaller cross-sectional area. The pulsed regime enables use of compact cables without suffering from continuous thermal loading.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables faster treatment times, reduced thermal effects, and the ability to use smaller diameter cables for electrosurgical procedures, improving patient comfort and the effectiveness of energy targeting while prolonging the apparatus's operational life.
Implementation Method 1
an amplifier module connect to the modulator and arranged to increase the power of pulses of microwave EM radiation received therefrom, the amplifier module comprising an array of amplifiers connected in parallel, wherein output signals from the array of amplifiers are combined to produce an output microwave signal
Implementation Method 2
a modulator arranged to pulse the microwave EM radiation
Implementation Method 3
a microwave signal generator for generating microwave electromagnetic (EM) radiation
Implementation Method 4
a feed structure for conveying the output microwave signal to a probe
Data Source
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AI summary
An apparatus capable of generating high power microwave frequency pulses for use with an electrosurgical device. The apparatus may be used for coagulating or ablating biological tissue. The apparatus includes an amplifier line-up comprising: a microwave signal generator for generating microwave radiation; a modulator arranged to pulse the microwave radiation; and an amplifier module arranged to increase the power of pulses of microwave radiation. The amplifier module works by providing a set of amplifiers that exhibit a gain that is greater than the total loss experienced at the components that divide the input signal and then combine the output signals. For example, if each amplifier in the array has a gain of 10 dBm, it is viable to use conventional power splitters and combiners to obtain an output microwave signal with substantially higher power than is provided by conventional electrosurgical generators.