Biomedical Engineering Reference
In-Depth Information
Polyethylene foam
Aluminum
Resistive cloth
Incident wave
Coating (paint)
FIGURE 5.10
Quarter-wavelength absorber using resistive cloth.
0
Theory
Measured
-10
-20
-30
(d = 7.4 mm)
C(d = 6.7 mm)
B
A(d = 8.2 mm)
-40
-50
8
9
10
Frequency (GHz)
11
12
FIGURE 5.11
Frequency-matching characteristics when changing thickness of
absorber.
matching frequency band over 2 GHz with a reflection coefficient below
20
dB. When the absorber is submitted to a TM wave with an oblique incidence,
the reflection coefficient remains under
-
20 dB up to 30 degrees of oblique-
ness. This absorber was improved further to bear environmental factors using
a resistance cloth laminated by chlorosulfone polyethylene rubber.
-
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