Reactively-Loaded Loop Microwave Antenna Impedance Matching
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Solution Overview
Problem
Microwave ablation procedures face inefficiencies due to impedance mismatches between coaxial cables, radiating sections, and tissue, leading to compromised energy delivery and desired tissue effects.
Innovation Solution
A microwave antenna with a reactively-loaded loop configuration, where the inner conductor loops back around the outer conductor of the coaxial cable, incorporating reactive components like inductive and capacitive elements, is used to achieve impedance matching and optimize energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional coaxial cable feed is used to transmit microwave energy to the radiating section, then the structure is simple and easy to manufacture, but impedance mismatch occurs between the coaxial cable, radiating section, and tissue, leading to compromised energy delivery efficiency
Solution Approach 1:
The inner conductor is designed with a reactively-loaded loop configuration that dynamically adjusts the impedance characteristics of the radiating section. The loop structure with reactive components (inductors and capacitors) creates a tunable impedance profile that can be optimized to match the coaxial cable and tissue impedances, thereby improving energy delivery efficiency while maintaining a manageable structural complexity
Solution Approach 2:
The patent modifies the impedance parameters of the radiating section by incorporating reactive components into the loop configuration. By changing the electrical parameters (inductance and capacitance values) of the loop structure, the impedance is transformed to achieve better matching with the coaxial cable and tissue, resolving the energy loss issue without requiring complete structural redesign
2Reliability
If the inner conductor loops back around the outer conductor to form a reactively-loaded loop configuration, then impedance matching is improved, but the manufacturing complexity increases
Solution Approach 1:
The radiating section is segmented into distinct functional portions: the loop configuration portion and the linear extension portion. This segmentation allows each section to be optimized independently - the loop portion for impedance matching and the linear portion for simple connection to the coaxial cable - thereby improving reliability while facilitating easier manufacturing through modular construction
Solution Approach 2:
The loop configuration acts as an intermediary element between the coaxial cable feed and the radiating section. By introducing this intermediate structure with controlled reactive components, the patent creates a transition zone that facilitates impedance transformation, improving the overall impedance matching without requiring direct complex integration between the cable and radiating section
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
The reactively-loaded loop configuration enhances impedance matching, improving energy delivery efficiency and allowing for more effective tissue ablation by ensuring optimal energy transfer to the target tissue site.
Implementation Method 1
For optimal energy delivery efficiency from the microwave generator to the microwave antenna, impedance associated with the coaxial cable, the radiating section and/or tissue need to equal to one another, i.e., an impedance match between the coaxial cable, the radiating section and/or tissue
Implementation Method 2
The microwave energy is able to non-invasively penetrate the skin to reach the underlying tissue
Implementation Method 3
Microwave ablation procedures, e.g., such as those performed for menorrhagia, are typically done to ablate the targeted tissue to denature or kill the tissue
Data Source
AI summary
A microwave ablation system is provided. The microwave ablation system includes a power source. A microwave antenna is adapted to connect to the power source via a coaxial cable feed including an inner conductor defining a portion of a radiating section of the microwave antenna, an outer conductor and dielectric shielding. The inner conductor loops back around and toward the outer conductor of the coaxial cable feed such that a distal end of the inner conductor is operably disposed adjacent the dielectric shielding. The inner conductor includes one or more reactive components disposed thereon forming a reactively-loaded loop configuration configured to maximize delivery of microwave energy from the power source to tissue such that a desired effect to tissue is achieved.