Biomedical Engineering Reference
In-Depth Information
0
Ferrite thickness
6.5 mm
Ferrite thickness
5.0 mm
Ferrite thickness
4.0 mm
-20
Envelope
Original matching
characteristic
Hole size large
f
Frequency
FIGURE 5.24
Matching characteristics with ferrite thickness as parameter
(
f
= 2.45 GHz,
Kf
1
= 4.5 GHz,
K
= 3, e
r
= 14).
0
Ferrite thickness
6.5 mm
Ferrite thickness
5.0 mm
Ferrite thickness
4.0 mm
-20
Envelope
Original matching
characteristic
Adjacent hole space small
f
Frequency
FIGURE 5.25
Matching characteristics with ferrite thickness as parameter
(
f
= 4.0 GHz,
Kf
1
= 4.5 GHz,
K
= 3, e
r
= 14).
required. Finally, the reason for the matching characteristics being changed
and improved is considered based on the following principle: The equivalent
values of permittivity and permeability decrease by punching small holes in
the ferrite. As a result, the matching frequency rises to a higher frequency
region. Figure 5.27 shows a simulation in which the value of permittivity is
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