Uncooled Insulated Monopole Antenna for Microwave Ablation: Improved Performance with Coaxial Cable Annealing
Abstract
Featured Application
Abstract
1. Introduction
2. Materials and Methods
2.1. Polytetrafluoroethylene (PTFE)
2.2. RG405 Coaxial Cable’s Annealing Process
2.3. Insulated Monopole Antenna Fabrication
2.4. Developed Coaxial Cable PTFE Thermal Expansion Characterisation System
2.5. Coaxial Cable PTFE Thermal Expansion Characterisation Experiment
2.6. Microwave Ablation System
2.7. Microwave Ablation Experiments
2.8. Ablation Zone Extraction
3. Results and Discussion
3.1. PTFE Thermal Expansion
3.2. Comparison of Return Loss Before and After Ablation
3.3. Investigation of Return Loss During Ablation
3.4. Lesions’ Ellipticity Analyses
3.5. Discussion of the Practical Advantages of Annealing for Uncooled Monopole Antennas
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Nomenclature
Acronyms | Descriptions |
PTFE | Polytetrafluoroethylene |
α1 | Coefficient of linear thermal expansion in °C−1 |
L0 | Initial length in m |
ΔL | Expansion in m |
ΔT | Change in temperature in °C |
VNA | Vector network analyser |
NI | National Instruments |
εTap | Complex permittivity of tap water |
εDI | Complex permittivity of deionised water |
f | Ellipticity |
a | Length of the major axis in pixels |
b | Length of the minor axis in pixels |
ΔL | Mean of the change in PTFE length in mm |
σΔL | Standard deviation of the change in PTFE length in mm |
L0 | Mean initial length measured using a toolmaker’s microscope in mm |
Tss | Steady state temperature in °C |
Tg | Glass transition temperature in °C |
RWA | Mean return loss at 2.45 GHz for annealed antennas in dB |
σRWA | Return loss standard deviation at 2.45 GHz for annealed antennas in dB |
RWN | Mean return loss at 2.45 GHz for non-annealed antennas in dB |
σRWN | Return loss standard deviation at 2.45 GHz for non-annealed antennas in dB |
Pfwd | Forward power in dBm |
Pref | Reflected power in dBm |
R | Return loss in dB |
Rs | Mean return loss for each one-second time sample in dB |
σRs | Return loss standard deviation for each one-second time sample in dB |
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Time | Annealed | Non-Annealed | ||
---|---|---|---|---|
Rs | σRs | Rs | σRs | |
0 s | 11.65 dB | 1.6 dB | 10.82 dB | 0.09 dB |
21 s | 18.30 dB | 5.25 dB | 15.76 dB | 1.78 dB |
60 s | 9.41 dB | 0.83 dB | 8.73 dB | 0.96 dB |
120 s | 7.84 dB | 0.90 dB | 7.64 dB | 0.75 dB |
180 s | 7.41 dB | 1.08 dB | 7.33 dB | 0.55 dB |
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Cilia, F.; Farrugia, L.; Sammut, C.; Rochman, A.; Bonello, J.; Farhat, I.; Dimech, E.J. Uncooled Insulated Monopole Antenna for Microwave Ablation: Improved Performance with Coaxial Cable Annealing. Appl. Sci. 2025, 15, 6616. https://doi.org/10.3390/app15126616
Cilia F, Farrugia L, Sammut C, Rochman A, Bonello J, Farhat I, Dimech EJ. Uncooled Insulated Monopole Antenna for Microwave Ablation: Improved Performance with Coaxial Cable Annealing. Applied Sciences. 2025; 15(12):6616. https://doi.org/10.3390/app15126616
Chicago/Turabian StyleCilia, Federico, Lourdes Farrugia, Charles Sammut, Arif Rochman, Julian Bonello, Iman Farhat, and Evan Joe Dimech. 2025. "Uncooled Insulated Monopole Antenna for Microwave Ablation: Improved Performance with Coaxial Cable Annealing" Applied Sciences 15, no. 12: 6616. https://doi.org/10.3390/app15126616
APA StyleCilia, F., Farrugia, L., Sammut, C., Rochman, A., Bonello, J., Farhat, I., & Dimech, E. J. (2025). Uncooled Insulated Monopole Antenna for Microwave Ablation: Improved Performance with Coaxial Cable Annealing. Applied Sciences, 15(12), 6616. https://doi.org/10.3390/app15126616