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4.2
Maximum Magnetic Field Strength That Can Be Generated
4.3
Magnetic Field Strength Boundaries for Countries With RMS Regulations
(4-2)
Maximum Magnetic Field Strength That Can Be Generated
There is a direct relationship between the magnetic field strength that is generated by the gate antenna
and the antenna voltage on the terminals of the antenna. The maximum voltage is provided in
. The relationship between the antenna voltage and the magnetic field is a linear function.
The magnetic field strength at 1 m and 3 m distance from the antenna appears in
Table 4-1. Magnetic Field Strength Generated With
1000-V Peak-Peak Antenna Voltage
H in Peak Value
H in Peak Value
Antenna Type
at 1 Meter
at 3 Meters
G01C
2012 mA/m
83 mA/m
G02C
707 mA/m
26.5 mA/m
G03C
3680 mA/m
168.2 mA/m
S01C
216 mA/m
8 mA/m
The antenna voltage of
is for each antenna at 1000 V
peak-to-peak
. Because the relationship is
linear, you can calculate the magnetic field strength for a different antenna voltage very easily. You just
divide the antenna voltage by 1000 and multiply the result with the value in
The values above are valid for antenna inductance of 27
µ
H; because the TIRIS gate antennas have a
small tolerance, you can always use this value for them. If you want to know the field strength exactly, you
must measure the inductance, then divide the measured inductance by 27
µ
H and multiply this value by
the magnetic field strength you calculated (for the antenna voltage previously calculated).
Countries where the Government Agency regulations allow for RMS calculations have an advantage over
countries that do not use RMS. For these countries, it is possible to use a higher magnetic field strength,
which means that TIRIS installations do not need such a long charge-up time.
The relation between charge-up/receive time and magnetic field strength is shown in
Comment: USA has a RMS in a 100 ms window. This means TX + RX = 100 ms. TX must be the worst
case (longest used charge-up time).
Example: For the standard 50 ms charge-up and 40 ms receive time:
TX = 60 ms and TX + RX = 100 ms.
22
Antenna Voltage and Field Strength
SCBU025 – November 1996
Summary of Contents for TIRIS SCBU025
Page 1: ...Antenna Reference Guide November 1996 SCBU025...
Page 2: ...Antenna Reference Guide Literature Number SCBU025 November 1996...
Page 6: ...www ti com 6 SCBU025 November 1996 Submit Documentation Feedback...
Page 20: ...www ti com Noise Characteristics 20 SCBU025 November 1996 Submit Documentation Feedback...
Page 30: ...www ti com Mechanical Characteristics 30 SCBU025 November 1996 Submit Documentation Feedback...
Page 34: ...www ti com Theory of Coupled Inductors 34 SCBU025 November 1996 Submit Documentation Feedback...