Figure 5. Deviation of the reconstructed signal from the originally defined
In the case of a three-parameter problem, when it becomes necessary to measure
all three fundamental parameters ε, tgδ and h
Z
, the way to increase the number of
measurements at each scan point for different gaps h
Z
does not seem to be the right
choice, since the approximation step due to the number of repetitions will be a fairly
time-consuming process. Let’s search for an alternative path
As shown above, the gap between the tip of the probe and the surface of the
sample has a very strong effect on the magnitude of the fundamental signals. The tip
end area and its shape determine the locality and sensitivity of the sensor [10, 11]. In
previous developments it was shown that the locality is comparable with the tip area,
and the sensitivity is determined by the inclusion factor of the object in the microwave
field of the resonator. Quantitatively this coefficient is determined by the next relation:
2
2
((r,,,
,tg
))rdrdzd
((r,,,
,tg
))rdrdzd
SS
Vobject
incl
SS
Vresonator
Еz
К
Еz
=
,
(4)
From obvious physical considerations it is clear that the influence of the gap is
manifested primarily through the value of K
incl
.
Approximate mathematical expressions for the fundamental signals of the
measurement information through the coefficient K
incl
have the next form [28]:
(
1)К
s
incl
f
f
=−
,
(5)
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