Biomedical Engineering Reference
In-Depth Information
(a)
6mm
(b)
Vacuum
D
Glycerine
Head inserted
antenna
Fig. 7.9
a Insertion of the antenna in the head b IR-UWB implantable antenna
Fig. 7.10 Simulated S11 for
the two different implant
orientations, IEEE copyright
[
39
]
ð
P
rad
P
tissue
Þ
G
¼
4p
ð
7
:
13
Þ
P
i
where G is the three dimensional gain, P
rad
is the power radiated per unit solid
angle, P
tissue
is the power absorbed by tissues within the unit solid angle and P
i
is
the accepted power of the antenna after the antenna reflections. It should be noted
that the antenna gain is high for antenna positions corresponding to low tissue
absorptions.
7.4.2 SAR Variation for Different Signal Power Levels
10 g averaged SAR variations for three different signal power levels are analyzed
for a 30-year-old adult head model using the developed simulation models
(Fig.
7.11
). The first scenario uses a FCC regulated IR-UWBIR-UWB pulse,
which lies within the specified -41.3 dBm/MHz limit. The second scenario is
obtained by considering the results in Fig.
7.11
a, c: it can be observed in the latter
