Microwave Antenna With Cooled Hub and Tunable Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microwave antennas have a narrow operational bandwidth, leading to a mismatch between the microwave delivery system and tissue due to changes in tissue dielectric properties during ablation procedures, resulting in inefficient energy delivery and dispersion.
Innovation Solution
A microwave antenna assembly with a coolant system that circulates dielectric coolant fluid through the antenna, maintaining a consistent impedance match by moderating changes in tissue dielectric properties and preventing near-field dielectric property changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional microwave antennas are used, then the structure is simple, but the operational bandwidth is narrow and impedance match deteriorates during ablation
Solution Approach 1:
The patent applies dynamics by making the antenna electrically tunable through varactor diodes that can change the electrical length of antenna segments. This allows the antenna to dynamically adjust its resonant frequency and impedance characteristics to match changing tissue dielectric properties during ablation, thereby maintaining broadband operation and impedance match throughout the procedure.
Solution Approach 2:
The patent changes physical parameters by using variable capacitance elements (varactor diodes) to adjust the electrical parameters of the antenna. By varying the capacitance values, the resonant frequency and impedance of the antenna can be tuned to maintain optimal performance across different tissue conditions and frequencies, expanding the operational bandwidth.
2Productivity
If microwave energy is applied to tissue, then tissue ablation is achieved, but the dielectric constant of surrounding tissue decreases causing wavelength increase and impedance mismatch
Solution Approach 1:
The patent implements feedback by using a reflection detector to monitor the impedance match between the microwave delivery system and the tissue. The detected reflected power signal is fed back to control the varactor diodes, automatically adjusting the antenna's electrical characteristics to maintain impedance match and compensate for tissue dielectric changes during ablation.
Solution Approach 2:
The patent changes electrical parameters in real-time by adjusting the capacitance of varactor diodes based on tissue dielectric property changes. This dynamic parameter adjustment compensates for the decrease in tissue dielectric constant during ablation, maintaining consistent wavelength and impedance match throughout the procedure.
3Device complexity
If narrow band microwave antennas are used, then the device complexity is low, but energy delivery efficiency decreases due to detuning
Solution Approach 1:
The patent applies dynamics by implementing an electrically tunable antenna system that can adapt its resonant frequency and impedance characteristics. This dynamic adjustment capability allows the antenna to maintain optimal energy delivery efficiency across a wide frequency range and under varying tissue conditions, overcoming the limitations of fixed-frequency narrowband antennas.
Solution Approach 2:
The patent achieves universality by designing an antenna system that can operate effectively across multiple frequencies and tissue conditions. The combination of varactor-tuned elements and reflection-based control enables the single antenna to perform multiple functions: maintaining impedance match, adapting to different tissue dielectric properties, and delivering energy efficiently across a broad operational bandwidth.
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 coolant system ensures consistent energy delivery and dispersion by maintaining impedance match and reducing power dissipation zone length, enhancing the effectiveness of microwave ablation procedures.
Implementation Method 1
a coolant assembly for circulating a dielectric coolant fluid through the microwave antenna
Implementation Method 2
maintaining a consistent impedance match by moderating changes in tissue dielectric properties and preventing near-field dielectric property changes
Data Source
AI summary
According to one aspect of the present disclosure, a microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The antenna assembly also comprises a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The antenna assembly further includes a connection hub having cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port. The connection hub includes a bypass tube configured to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port.