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INSTRUCTION MANUAL
AL-RE101
LOOP ANTENNA
SECTI ON 6
-
CALIBRATION
1912 1 E l T o ro R d
●
Si l vera do, Ca lifo rni a 9 26 76
●
(9 49) 459 -96 00
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co m-p o wer. com
Rev101617
6.3 Calibration
Methodology
The calibration of the AL-RE101 antenna is performed by generating a known
magnetic field using the AL-RS101-TX Antenna, which is a 12 cm diameter loop
antenna having 20 turns of 12 gauge enamel insulated wire. The calibration is
performed with a separation distance of 12 cm between the perpendicular loop
faces, with the centers of the loops aligned along the same axis, as shown in
Figure 5
and
Figure 6
.
The current through the transmit loop is monitored in order to determine the
magnetic field strength (flux density) that is present at a distance of 12 cm. This
quantity is calculated using
Equation (F)
below:
So, under the above conditions, the measured value
(in dB
μ
V)
on the measuring
instrument connected to the AL-RE101 Loop Antenna, at any given frequency;
plus the respective, appropriate antenna conversion factor
(based on the
frequency and instrument input impedance)
, should be approximately equal to
125.45 dBpT ±2 dB
. When the antenna meets this condition over the frequency
band of operation, it is considered to be calibrated.
EQUATION (8)
where:
= magnetic flux density
(in Tesla)
I
= current through loop coil
=
0.1
Amps
N
= number of turns in loop coil =
20
turns
r
= radius of the loop coil =
0.06
meters
d
= separation distance between the Tx and Rx loops =
0.12
meters
μ
-7
= permeability of air
=
4
π
x 10 H/m
=
1.25664 x 10
H/m
-6
B
(Tesla)
=
[1.25664 x 10 ]
x
[0.1]
x
[20]
x
[0.06]
-6
2
2 (
[0.06]
+
[0.12]
)
(3/2)
2
2
B
(Tesla)
=
[1.25664 x 10 ]
x
[0.1]
x
[20]
x
[0.0036]
-6
2 (
[0.0036]
+
[0.0144]
)
(3/2)
B
=
1.873288 x 10
Tesla
-6
B
=
1,873,288
pT
([Tesla] x 10 )
12
B
=
125.45
dBpT
(20Log[pT])
B
(Tesla)
=
μINr
2
2 (r + d )
2
2 (3/2)
B
125.45
dBpT
(± 2 dB)
≅
Measured
Value
(in dBμV)
Antenna
Conversion
Factor
(in dBpT/μV)
+
