Model of an inductive sensor of cardiac activity attached to patient

Abstract

An electric circuit model describing an inductive sensor of cardiac mechanical activity in its working condition has been developed. The sensor comprises a single-turn coil which is fed by 7.7 MHz constant current and induces probing eddy currents in the body. The inductor is considered to be attached to the thoracic surface of a normal human male, in front of the heart. A simple axial-symmetric model of the thorax, formed of tightly packed circular current tubes, has been used to calculate the resistances, self-inductances and mutual inductances within the human body. Then the inductor and the eddy currents in the body were reduced to a system of two inductively coupled coils; estimates of the parameters and frequency response of the system have been found; the active and reactive contributions of the human body to the resulting impedance of the inductor were calculated.

Modelling of an inductive sensor of the Foucault cardiogram

“…Although the electromotive forces in all the elementary coils have the same phase, the currents there have different phase shifts determined by particular tissues involved. This feature causes differences between the present model with its complex impedivities and the model [ 4 ] with tissues having purely active resistivities. Starting now from the equal complex power S % requirement…”

The MAIN Shirt: A Textile-Integrated Magnetic Induction Sensor Array

“…This is based on the fact that the reinduced field, B 2 , affects the primary one, B 1 , and, hence, changes the so-called reflected impedance of the coil [ 17 ]. A way of describing this measurement principle is to regard the sensor coil as the primary coil and the eddy currents in their collective as the secondary coil of a traditional transformer model with mutual inductance M 12 (see Figure 1 ) [ 10 , 17 , 18 ].…”