Then, the effect of impedance mismatch increases because the reflected impedance changes depending on the degree of coupling.
5(a) with the reflected impedance, Zr, from the receiver for simplifying the calculation of the input impedance of transmitter [17, 18].
The reflected impedance is dependent on the coupling coefficient and operating frequency, and can be found by dividing the reflected voltage by the transmitter current resulting in
With the reflected impedance in (7), the input impedance at resonant frequency can be calculated.
Because the reflected impedance only has real values at the resonant frequencies regardless of the separation distance, the loci of [S.
Since the latter varies with cardiac contractions, cardiac-related modulation of the reflected impedance results.
Further in this paper, we will consider the variation of the reflected impedance as the output of the present sensor.
The inductive sensor transforms the secondary circuit impedance into the reflected impedance [DELTA][Z.
The reflected impedance can be found using the mutual inductance model of the coreless transformer, which leads to the following well-known  formula, but where the parameters now are complex-valued (phasors):
Also, the primary may be an open circuit and the reflected impedance
exaggerating the impedance to the in-rush current.
This is not always true, however, as the reflected impedance
on the primary changes with frequency.
1] remains stable after dynamic change in a period of time, which means reflected impedances
from secondary side to primary side maintain being constant.