Modelling the Nonlinear Properties of Ferroelectric Materials in Ceramic Capacitors for the Implementation of Sensor Functionalities in Implantable Electronics

For several years, innovative and individualized therapy approaches with minor side effects using electroceuticals have been under development. In the future, electroceuticals will gain importance due to their broad range of applications in therapeutic approaches, such as against, chronic pain, rheumatoid arthritis, obstructive sleep apnea and cardiovascular diseases, to name but a few. Conventional electronic implants, such as hypoglossal nerve stimulators and vagus nerve stimulators, contain complex circuits composed of a large number of active electronic components, sensors and a voluminous battery unit. However, there is a need for miniaturization without impairing functionality and reliability to expand the field of application of electronic implants. Notable examples of these can be found among implantable microstimulators and biosensors. In this paper, tiny electronic implants with applications in functional electrostimulation are considered that contain neither batteries nor sensors or active electronic components. These are not intended for autonomous operation and require an extracorporeal wearable device. The utilization of intrinsic nonlinear properties of ferroelectric materials in ceramic capacitors could allow the implementation of sensor functionalities in microstimulators and tiny wearable devices. The focus of this work is on the use of these sensor functionalities for the development of a novel energy control concept. Energy is supplied via inductive coupling for frequencies below 1 MHz. A mathematical model was implemented using Mathcad Prime 3.1. This nonlinear model includes the hysteresis modeling of ferroelectric materials. For model validation, comparative calculations were performed with ANSYS 2019 R2.