Minimum Representative Human Body Model Size Determination for Link Budget Calculation in Implanted Medical Devices

Abstract

In this work, the optimum homogeneous phantom size for an equivalent whole-body electromagnetic (EM) modeling is calculated. This will enable the simple characterization of plane wave EM attenuation and far-field link budgets in Active Medical Implant (AMI) applications in the core region of the body for Industrial, Scientific, Medical and MedRadio frequency bands. A computational analysis is done to determine the optimum size in which a minimum phantom size reliably represents a whole-body situation for the corresponding frequency of operation, saving computer and laboratory resources. After the definition of a converge criterion, the computed minimum phantom size for subcutaneous applications, 0–10 mm insertion depth, is 355 × 160 × 255 mm3 for 402 MHz and 868 MHz and a cube with a side of 100 mm and 50 mm for 2.45 GHz and 5.8 GHz, respectively. For deep AMI applications, 10–50 mm insertion depth, the dimensions are 355 × 260 × 255 mm3 for 402 MHz and 868 MHz, and a cube with a side of 200 mm and 150 mm for 2.45 GHz and 5.8 GHz, respectively. A significant reduction in both computational and manufacturing resources for phantom development is thereby achieved. The verification of the model is performed by field measurements in phantoms made by aqueous solutions with sugar.

Colonic Electrical Stimulation for Chronic Constipation: A Perspective Review

“…However, if battery lifetime in implants is limited to some weeks or months due to the high energy demand of stimulation with respect to amplitude or stimulation frequency like in cochlear implants, wireless energy supply is desirable [ 107 ]. While electromagnetic inductive coupling has been established in cochlear implants, mid- or far-field coupling via radio frequency, ultrasound, or light are discussed as alternative methods [ 108 , 109 , 110 ]. They all include options of bi-directional data transmission to adapt the stimulation parameters in open- and closed-loop control and to send out data to a patient-worn user interface ( Figure 3 a).…”