A Time-Efficient Model for Estimating Far-Field Wireless Power Transfer to Biomedical Implants

This paper presents a time-efficient, far-field ana-lytical model for wireless power transfer in the human body for biomedical implantable applications. The proposed method presents a means of rapidly computing received RF power levels in an implantable device compared to finite-element methods. For the first time, the Cole-Cole Dispersion Model and Transfer Matrix Method are combined to model frequency dependent dielectric and signal reflection losses in a multi-layered biological tissue structure. This model can be applied to any arbitrary N-layer biological tissue profile. The model was validated using Ansys HFSS at 403.5 MHz, and can estimate the received RF power at the implant with a mean error of 3.27 dB, compared to FEM methods. In addition, the presented model computes in a fraction of the time, 280 ms versus 39 minutes, for the studied simulation test-case. This model is useful for preliminary analysis of potential performance of implantable devices.