Adjustable Outer Conductor Impedance Matching in Microwave Ablation
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Solution Overview
Problem
Impedance mismatches between coaxial cables, radiating sections, and tissue in microwave ablation procedures lead to decreased energy delivery efficiency, compromising the effectiveness of microwave ablation treatments.
Innovation Solution
A microwave ablation system with a coaxial cable featuring an adjustable outer conductor configuration, where the distal end of the outer conductor transitions from an initial to a subsequent diameter, enhancing impedance matching between the inner conductor, compressible dielectric, and radiating section, thereby optimizing microwave energy transfer to the tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed diameter outer conductor is used in the coaxial cable, then the structure is simple and easy to manufacture, but impedance mismatch occurs between the coaxial cable and radiating section, decreasing energy delivery efficiency
Solution Approach 1:
The outer conductor's distal end is made dynamically adjustable rather than fixed, allowing it to transition between different diameters. This dynamic configuration enables impedance matching between the coaxial cable and radiating section, thereby improving energy delivery efficiency without permanently complicating the device structure.
Solution Approach 2:
The diameter of the outer conductor's distal end is changed as a variable parameter. By transitioning the distal end between different diameter conditions (first diameter and second diameter), the impedance characteristics of the coaxial cable are adjusted to match the radiating section, reducing energy loss.
2Loss of energy
If the outer conductor distal end is made adjustable to improve impedance matching, then energy delivery efficiency improves, but the device complexity and difficulty of operation increase
Solution Approach 1:
The outer conductor incorporates a movable distal end that can dynamically adjust its diameter. This dynamic feature allows the system to adapt impedance conditions during operation, improving energy delivery while maintaining operational flexibility through controlled movement rather than complex mechanisms.
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 adjustable coaxial cable design improves energy transfer efficiency by compensating for impedance mismatches, ensuring effective tissue ablation and enhancing the delivery of microwave energy during procedures.
Implementation Method 1
having a compressible dielectric operably disposed therebetween. The inner conductor in operative communication with a radiating section associated with the microwave antenna. The outer conductor includes a distal end transitionable with respect to each of the inner conductor, compressible dielectric and radiating section from an initial condition wherein the distal end has a first diameter to a subsequent condition wherein the distal end has second diameter
Implementation Method 2
microwave energy is generated by a power source, e.g., microwave generator, and transmitted to tissue via a microwave antenna that is fed with a coaxial cable
Implementation Method 3
To enhance 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
Data Source
AI summary
A microwave ablation system includes a power source. A microwave antenna is adapted to connect to the power source via a coaxial cable that includes inner and outer conductors having a compressible dielectric operably disposed therebetween. The inner conductor in operative communication with a radiating section associated with the microwave antenna. The outer conductor includes a distal end transitionable with respect to each of the inner conductor, compressible dielectric and radiating section from an initial condition wherein the distal end has a first diameter to a subsequent condition wherein the distal end has second diameter. Transition of the distal end from the initial condition to the subsequent condition enhances the delivery of microwave energy from the power source to the inner conductor and radiating section such that a desired effect to tissue is achieved.