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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
5.2 Determination
of
Antenna Conversion Factors
The basic formulae for determining the antenna conversion factors for the
antenna are given in
Equation (5)
and
Equation (6)
. Considered in these
equations are the frequency and resistance, inductance, area and number of
turns of the loop coil:
The derivation of
Equation (6)
is given in section 5.1.1.
In the formulae below,
Equation (6)
is reformulated to integrate the actual
resistance
(R
C
)
, inductance
(L)
, number of turns
(N)
and coil area
(A)
for the AL-
RE101 Loop Antenna; in
Equation (7)
:
where:
R
L
= load resistance
[or input impedance of measurement instrument]
(in ohms)
R
C
= loop coil resistance =
10Ω
L
= loop coil inductance
=
0.00034 H
V
L(μV)
= voltage across R
(in μV)
L
ƒ
N
= number of turns in loop coil =
36 turns
= frequency
(in Hz)
A
= area of coil
=
0.0139 meters
2
=
π
r
,
where
r
= coil radius =
0.0665 meters
2
(pT)
B
= magnetic flux density
(in pT)
= antenna conversion factor
(in pT/μV)
ACF
EQUATION (5)
EQUATION (6)
ACF = 20Log
(dBpT/μV)
V
L(μV)
(pT)
B
( )
=
[pT/μV]
V
L(μV)
B
(pT)
10
6
2
π
ƒ
AN
R
C
R
L
1
+
( )
2
R
L
+
( )
2
2
π
ƒ
L
EQUATION (7)
rearranging equation (6) to separate
2
π
L
from
ƒ
...
2
π
ƒ
AN
(pT/μV)
=
10
6
R
C
R
L
1
+
( )
2
+ (
2
π
L
)
(
)
2
R
L
ƒ
2
V
L(μV)
(pT)
B
substituting known constants (
coil resistance
(R )
, coil inductance
(L)
,
number of turns
(N)
and
coil area
(A)
)...
C
equation (7) is determined...
2
π
x
ƒ
x
[0.0139]
x
[36]
(pT/μV)
=
10
6
[10]
R
L
1
+
( )
2
+ (2
π
x
[0.00034]
)
( )
2
R
L
ƒ
2
V
L(μV)
(pT)
B
ƒ
x
[3.144]
(pT/μV)
=
10
6
[10]
R
L
1
+
( )
2
+
[4.564x10 ]
( )
2
R
L
ƒ
-6
V
L(μV)
(pT)
B
