Microwave Waveguide Impedance Matching via Adjustable Capacitor
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Solution Overview
Problem
Conventional microwave transmission apparatuses have limited impedance matching range and operating frequency range due to fixed impedance matching structures, making them inflexible for varying load conditions.
Innovation Solution
The use of a microstrip interdigital capacitor with adjustable equivalent capacitance and position within the waveguide allows for dynamic impedance matching, expanding the impedance adjustment range and applicable frequency scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed impedance matching structure (metal pin or metal diaphragm) is used in the waveguide, then the structure is simple and easy to manufacture, but the impedance matching range is limited and cannot adapt to load changes
Solution Approach 1:
The patent applies the dynamics principle by replacing fixed impedance matching structures with adjustable ones. Specifically, it uses adjustable screws that can be moved along the waveguide walls to change the equivalent capacitance and inductance values, enabling dynamic adaptation to different load conditions and expanding the impedance matching range while maintaining manufacturing simplicity
Solution Approach 2:
The patent implements parameter changes by modifying the physical position and insertion depth of adjustable screws in the waveguide. By changing the screw positions, the equivalent electrical parameters (capacitance and inductance) are adjusted, allowing the impedance matching structure to adapt to varying load conditions and frequency ranges
2Adaptability or versatility
If an adjustable screw structure is used to form equivalent capacitor and inductor, then the impedance matching range is improved, but the adjustment range is limited by the fixed short side length of the waveguide
Solution Approach 1:
The patent applies the another dimension principle by utilizing the longitudinal direction of the waveguide (along the microwave propagation direction) as an additional adjustment dimension. The adjustable screws can be positioned at different locations along the waveguide length, providing an extra degree of freedom for impedance matching beyond what is available from cross-sectional adjustments alone
3Adaptability or versatility
If the waveguide short side length is increased to expand screw adjustment range, then the impedance matching range is improved, but the waveguide dimensions and device complexity increase
Solution Approach 1:
The patent uses dynamics by making the impedance matching structure adjustable rather than fixed. The screws can be dynamically repositioned along the waveguide to achieve different impedance matching conditions, eliminating the need to increase waveguide dimensions to expand the operating frequency range
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 enhances the absorption efficiency of microwaves in plasma sources, improving plasma stability and output beam intensity by accommodating a wider range of load variations and frequencies.
Implementation Method 1
the equivalent capacitance formed by a microstrip interdigital capacitor and/or a position of the microstrip interdigital capacitor along an extending direction of the waveguide is adjusted
Implementation Method 2
the waveguide is configured to transmit microwaves emitted from a microwave source to a load
Implementation Method 3
a microwave source, a microwave transmission apparatus, and a chamber for transmitting microwaves emitted from the microwave source to the chamber
Data Source
AI summary
The present disclosure provides a microwave transmission apparatus. The microwave transmission apparatus includes a waveguide, configured to transmit microwaves emitted from a microwave source to a load; and an impedance matching structure, disposed in the waveguide the waveguide. The waveguide includes a microstrip interdigital capacitor. The impedance before the input end of the impedance matching structure is matched with the impedance after the input end of the impedance matching structure by adjusting an equivalent capacitance formed by the microstrip interdigital capacitor and/or a position of the microstrip interdigital capacitor along the extending direction of the waveguide.