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INSTRUCTION MANUAL
AL-RE101
LOOP ANTENNA
SECTI ON 5
-
ANTENNA THEORY
1912 1 E l T o ro R d
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Si l vera do, Ca lifo rni a 9 26 76
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(9 49) 459 -96 00
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co m-p o wer. com
Rev101617
5.0
Antenna Theory
This section details the theoretical operation of the AL-RE101 loop antenna.
Equation (3)
through
Equation (7)
define the relationship between the average magnetic field
strength (or magnetic flux density) within the area of the loop coil and the voltage
present at the antenna terminals, in order to determine the antenna conversion factors.
These equations consider the physical and electrical characteristics for the antenna, as
shown in the following pages.
5.1 Open Circuit Antenna Terminal Voltage vs Flux Density
Equation (3)
below defines the relationship between open circuit loop terminal
voltage, number of turns in the coil, area of the coil, the frequency and the
average flux density within the area of the coil:
Equation (3)
is resolved below by substituting the actual number of turns
(N)
and
coil area
(A)
for the AL-RE101 Loop Antenna; and to provide the resultant
quantity in microvolts (rather than volts).
EQUATION (4)
e
=
2
π
NA
ƒ
B
(Volts)
i(V)
(T)
e
=
2
π
x
[36]
x
[0.0139]
x
ƒ
B
(Volts)
i(V)
(T)
e
=
[3.144]
x
ƒ
B
(Volts)
i(V)
(T)
substituting known constants (
number of turns
and
coil area
)...
converting
Volt/Tesla
units to more convenient
μV/pT
units...
e
i(μV)
(pT)
=
10
x
[3.144]
x
ƒ
B
(
μV
)
-6
ƒ
= frequency
(in Hz)
where:
= open-circuit loop terminal voltage
(in microvolts)
e
i(μV)
= magnetic flux density
(in picotesla)
B
(pT)
EQUATION (3)
A
ƒ
N
= number of turns in loop coil =
36 turns
= area of coil =
0.0139 meters
= frequency
(in Hz)
= magnetic flux density
(in Tesla)
2
=
π
r
,
where
r
= coil radius
=
0.0665 meters
2
where:
= open-circuit loop terminal voltage
(in Volts)
e
i(V)
B
(T)
e
=
2
π
NA
ƒ
B
(Volts)
i(V)
(T)
