Transcript OH6KVP Suuntakuvio

Suuntakuvio
OH6KVP
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Suuntaavuus
The ratio of the maximum power density
to
the average power density taken over the
entire sphere (which is the same as from
the isotropic antenna under the specified
conditions) is the numerical measure of
the directivity of the antenna. That is,
D=
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Vahvistus
k
Pt
Pin
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Vahvistus
ESIMERKKI:
If the efficiency of the antenna is 50%, the VSWR at the antenna input is 3
and the input/supplied power is 1 W, find:
a. the power gain;
b. the total radiated power
a.) We know the directivity D =1.5. Since the efficiency factor ηe
=50%= 0.5, the power gain:
b.) If the VSWR = 3, we can easily obtain the voltage reflection coefficient using Equat
this means a matching efficiency of 1 − 0.52 = 0.75 = 75%. Since the input
power is 1W,
the total input power accepted by the antenna is 0.75 W and the total radiated
power:
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