Biomedical Engineering Reference
In-Depth Information
1
0.9
0.8
0.7
0.6
0.5
10 MHz
0.4
0.3
27.12
0.2
40.68
433
100
915
0.1
2450
0
0
1
2
3
4
5
6
7
8
9
10
distance (cm)
FIGURE 1.8
Power absorbed in muscles as a function of the skin depth at various
frequencies.
10
7
10
6
10
5
10
4
10
3
10
2
10
1
10
0
10
0
10
2
10
4
10
6
10
8
10
10
10
12
frequency (Hz)
FIGURE 1.9
Dielectric constant of living material as a function of frequency.
it is the link between the source field and the electric flux density (also called
the displacement field). A dielectric constant 10,000 larger implies the possi-
bility of an electric flux density of a given value with a source field 10,000 times
smaller. Figure 1.9 shows the dielectric constant of living material (muscle) as
a function of frequency [18]. There is a level of about 1,000,000 at ELF up to
100 Hz, then a second level of about 100,000 from 100 Hz to 10 kHz, and, after
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