Segmented Coaxial Cable Structure for Flexible Microwave Ablation
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Solution Overview
Problem
Existing coaxial cables for microwave ablation probes lack flexibility and elasticity, leading to loss of desired trajectory and difficulty in navigating tortuous paths, while modifications for flexibility compromise microwave signal strength.
Innovation Solution
A coaxial cable with strategically designed cut-outs in the outer conductor, each less than half a wavelength of the operating frequency, maintains microwave signal strength and provides flexibility and elasticity, allowing navigation through tortuous paths without significant power leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a semi-rigid coaxial cable structure is used, then microwave signal strength is maintained, but flexibility and elasticity are compromised
Solution Approach 1:
The outer conductor is segmented by introducing a pattern of cuts that extend partially through its thickness, creating multiple discrete sections along the cable length. This segmentation allows the cable to bend and flex more easily while the remaining continuous portions maintain electrical conductivity and signal integrity.
Solution Approach 2:
The cuts in the outer conductor are designed with specific characteristics (partial depth, specific patterns such as spiral or axial) that provide flexibility in certain locations while maintaining structural integrity and electrical performance in other areas. The local modification of the outer conductor creates regions of different stiffness to enable navigation through tortuous paths.
2Ease of operation
If the outer conductor is made more flexible by removing material, then ease of navigation is improved, but microwave signal strength deteriorates
Solution Approach 1:
Instead of removing the entire outer conductor or making large cuts that would compromise signal integrity, the invention applies partial action by making cuts that extend only a portion of the way through the outer conductor thickness. This partial removal provides sufficient flexibility for navigation while leaving enough material to maintain electrical continuity and signal strength.
Solution Approach 2:
The invention changes the physical parameters of the outer conductor by controlling the depth, length, and pattern of cuts. By adjusting these parameters, the cable achieves the right balance between flexibility for navigation and electrical continuity for signal transmission, optimizing both ease of navigation and signal strength.
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4C
AI summary
A coaxial cable (102) for a microwave ablation probe (104) is disclosed. The alation probe (104) has an operating frequency at which microwave energy is delivered to target tissue. The coaxial cable (102) comprises: an inner conductor (202a); an outer conductor (202c); and a dielectric (202b) arranged between the inner conductor and the outer conductor. The outer conductor (202c) comprises a plurality of cut-outs (106). The cut-outs (106) each have a length less than 10% of the wavelength in free-space at the operating frequency of the ablation probe (104). Also disclosed is a microwave ablation system (100) and method (1000) of making a coaxial cable.