Buried Microstrip Transformer for RF Impedance Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing RF power supplies for CO2 lasers face challenges in impedance matching between the RF amplifier and the gas discharge, particularly at higher frequencies, leading to inefficiencies, increased design and assembly complexity, and higher costs due to the limitations of ferrite and co-axial transformer technologies, which struggle with thermal management and size constraints when integrated directly on the laser head.
Innovation Solution
A buried micro-strip and coupled micro-strip transformer design that provides high RF frequency step-up or step-down impedance matching, utilizing dielectric plates with embedded conductive strips and a ground plane electrode, allowing for efficient impedance transformation with reduced losses and increased reliability, and is suitable for direct integration on the laser head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher RF frequency is used to increase power coupling and reduce laser size, then laser output power and efficiency are improved, but design complexity, assembly difficulty and cost of the power supply increase
Solution Approach 1:
The patent replaces traditional mechanical/ferrite-based impedance matching components with a planar microstrip transmission line design that can be directly integrated onto the laser head PCB. This substitution eliminates complex mechanical assembly and ferrite material requirements while maintaining impedance matching functionality at higher RF frequencies.
Solution Approach 2:
The patent transitions from three-dimensional ferrite transformer components to a two-dimensional planar microstrip transmission line structure. This dimensional reduction allows the impedance matching network to be flat-mounted on the PCB, significantly reducing assembly complexity and enabling direct integration on the laser head.
2Reliability
If ferrite transformers are used for impedance matching at lower frequencies, then impedance transformation is achieved, but thermal management becomes problematic at higher frequencies and power levels
Solution Approach 1:
The patent changes the operating parameters of the impedance matching network by using microstrip transmission line geometry with controlled characteristic impedances (50 ohms, 25 ohms, 12.5 ohms) instead of relying on ferrite magnetic properties. This parameter change allows the system to operate efficiently at higher RF frequencies without the thermal losses inherent in ferrite materials.
Solution Approach 2:
The patent uses a composite structure combining copper conductive traces with a dielectric substrate material to create the microstrip transmission line. This composite construction provides both the electrical functionality for impedance matching and the thermal management capabilities of the dielectric substrate, eliminating the thermal problems associated with ferrite transformers.
3Adaptability or versatility
If co-axial transformers are used for impedance matching, then broadband high voltage capability is achieved, but device size and integration complexity on the laser head increase
Solution Approach 1:
The patent extracts the essential impedance matching function from the bulky co-axial transformer structure and implements it using planar microstrip transmission lines. This extraction eliminates the need for large three-dimensional transformer components while maintaining the broadband voltage handling capability through proper microstrip geometry design.
Solution Approach 2:
The patent reduces the impedance matching component from a three-dimensional co-axial transformer to a two-dimensional planar microstrip structure. This dimensional reduction dramatically decreases the volume required for the transformer, enabling direct integration on the laser head PCB without increasing overall device size.
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 efficient impedance matching with reduced RF losses and thermal management issues, enabling higher frequency operation while minimizing size and cost, thus enhancing the performance and reliability of RF power supplies integrated on the laser head.
Implementation Method 1
Transmission line transformers are inherently broadband so that they can deliver the high voltage 'spikes' and they are also very efficient under continuous wave (CW) operation.
Implementation Method 2
A transformer in accordance with one embodiment of the present invention comprises first and second dielectric plates each having an upper surface and a lower surface.
Data Source
AI summary
An RF impedance-matching transformer for matching the output impedance of an RF amplifier to the discharge of a gas-discharge laser includes upper and lower dielectric plates arranged face-to-face and bonded together. A primary U-shaped strip winding is embedded in the bonded surface of one of the dielectric plates. A secondary strip-winding is formed on an exposed surface of the upper dielectric plates. A ground-plane electrode formed on an exposed surface of the lower dielectric plate. An electrical connector connects one end of the secondary strip-winding to the ground-plane electrode via a via-hole extending through the dielectric plates. The other end of the secondary strip-winding can be connected to the laser.