Microwave Amplifier Load Network Harmonic Termination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Delivering microwave energy for electrosurgical treatments is challenging due to energy losses through surgical scoping devices, leading to undesirable endoluminal heating and longer treatment times, which affect patient comfort and recovery.
Innovation Solution
A microwave amplifier with a load network that provides efficient amplification of low power microwave signals, allowing the amplifier to be located closer to the applicator, reducing energy losses and enabling a portable generator unit for electrosurgical devices, using a class F configuration with tunable stubs to maintain impedance matching and achieve high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power signals are transmitted through the instrument cord to deliver sufficient microwave energy for tissue treatment, then the treatment effectiveness is improved, but large energy losses occur leading to undesirable endoluminal heating
Solution Approach 1:
A DC-DC converter is introduced as an intermediary device between the power source and the microwave amplifier. This converter efficiently transforms high voltage low current DC power into low voltage high current DC power, enabling the amplifier to operate at optimal power levels without requiring high power transmission through the instrument cord, thus reducing endoluminal heating while maintaining treatment effectiveness
Solution Approach 2:
The system changes the voltage and current parameters of the power supply through the DC-DC converter. By transforming the power parameters to match the amplifier's optimal operating conditions, the system achieves high efficiency amplification without needing to transmit high power through the cord, thereby solving the heating problem
2Object-affected harmful factors
If lower power signals are transmitted through the instrument cord to reduce energy losses and heating, then endoluminal heating is reduced, but treatment times become longer
Solution Approach 1:
The DC-DC converter acts as a power optimization intermediary that enables the amplifier to receive power at optimal levels for efficient amplification. This allows the system to deliver adequate treatment power at the amplifier output without requiring high power transmission through the cord, thus maintaining short treatment times while reducing heating
Solution Approach 2:
By transforming power parameters through the DC-DC converter, the system optimizes the power delivery chain efficiency. The amplifier can achieve high output power with low input power requirements, maintaining effective treatment duration while minimizing energy losses in the transmission path
3Loss of energy
If a high efficiency amplifier with complex load network is used to reduce power requirements and improve efficiency, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The load network is designed to present specific impedance parameters at the amplifier output, transforming the amplifier's operating conditions to achieve optimal efficiency. By carefully controlling the impedance parameters and harmonic terminations, the system achieves high efficiency without requiring excessive complexity in the overall device architecture
Solution Approach 2:
The load network is segmented into distinct functional components: a fundamental matching network for impedance matching, a half-wave transmission line for second harmonic termination, and quarter-wave stubs for third harmonic termination. This segmentation allows each component to be optimized independently while working together to achieve high overall efficiency
4Loss of energy
If the amplifier is located closer to the applicator to reduce transmission losses, then energy delivery efficiency is improved, but the device becomes less portable and more complex to integrate
Solution Approach 1:
The system is segmented into modular components: a portable generator unit containing the oscillator and DC-DC converter, and a separate amplifier unit with its own power supply and load network. This segmentation allows the amplifier to be positioned close to the applicator for efficient energy delivery, while the generator remains portable and can be located remotely, reducing integration complexity
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 achieves high efficiency (at least 80%) in microwave energy delivery, reducing heating and treatment time, and allows for a smaller, portable electrosurgical apparatus with reduced power and cooling requirements.
Implementation Method 1
a transistor configured to provide an amplified microwave signal at an output thereof
Implementation Method 2
a fundamental matching network that is tunable to provide impedance matching at the fundamental frequency
Implementation Method 3
a quarter-wave stub for the second harmonic frequency and a quarter-wave stub for the fundamental frequency, arranged on the half-wave transmission line to provide a short circuit condition at the second harmonic frequency
Implementation Method 4
a half-wave transmission line for a second harmonic frequency of the amplified microwave signal, the half-wave transmission line being disposed between the output and the fundamental matching network
Implementation Method 5
a quarter-wave stub for the third harmonic frequency... arranged on the half-wave transmission line to provide an open circuit condition at the third harmonic frequency
Data Source
AI summary
A microwave amplifier having a load network which provides more efficient amplification of a low power microwave frequency signal. The amplifier comprises a transistor and a load network coupled to the transistor output to shape a waveform of an amplified microwave signal at the transistor current source plane. The load network comprises: a fundamental matching network to provide impedance matching at a fundamental frequency; a half-wave transmission line for a second harmonic frequency disposed between the transistor output and the fundamental matching network; a quarter-wave stub and a five-quarter-wave stub for a third harmonic frequency arranged on the half-wave transmission line to provide an open circuit condition at the third harmonic; and a quarter-wave stub for the second harmonic frequency and a quarter-wave stub for the fundamental frequency, arranged on the half-wave transmission line to provide a short circuit condition at the second harmonic frequency.