Maximum Radiation Efficiency of Arbitrarily Shaped Implantable Antennas
- Resource Type
- Periodical
- Authors
- Liska, J.; Gao, M.; Jelinek, L.; Algarp, E.R.; Skrivervik, A.K.; Capek, M.
- Source
- IEEE Transactions on Antennas and Propagation IEEE Trans. Antennas Propagat. Antennas and Propagation, IEEE Transactions on. 72(4):3507-3516 Apr, 2024
- Subject
- Fields, Waves and Electromagnetics
Aerospace
Transportation
Components, Circuits, Devices and Systems
Antennas
Method of moments
Optimization
Implants
Current density
Shape
Numerical models
Antenna efficiency
fundamental bounds
hybrid solution methods
implanted biomedical devices
numeric methods
ohmic losses
quadratic programming
tissue loss
- Language
- ISSN
- 0018-926X
1558-2221
Performance limitations for implanted antennas, taking radiation efficiency as the metric, are presented. The performance limitations use a convex optimization procedure with the current density inside the implant acting as its degree of freedom. The knowledge of the limitations provides useful information in design procedures and physical insights. Ohmic losses in the antenna and surrounding tissue are considered and quantitatively compared. The interaction of all parts of the system is taken into account in a full-wave manner via the hybrid computation method. The optimization framework is thoroughly tested on a realistic implanted antenna design that is treated both experimentally and as a model in a commercial electromagnetic (EM) solver. Good agreement is reported. To demonstrate the feasibility of developed performance limitations, they are compared to the performance of a loop and a dipole antenna showing the importance of various loss mechanisms during the design process. The tradeoff between tissue loss and antenna ohmic loss indicates critical points at which the optimal solution drastically changes and the chosen topology for a specific design should be changed.