MODEL 3140 BICONILOG™ ANTENNA
Application
© EMC TEST SYSTEMS, L.P. – MARCH 2002
13
REV C – PN 399258
field strength
E
can be obtained from Figure 12 or 13 in the
Typical Data section below, which shows forward power
required in Watts to generate 1 V/m. Note that while the
formula provided above is based on the net power (forward
minus reflected) transmitted by the antenna, the gain
determined from the antenna factor already contains effects
due to mismatch, so the formula then predicts the required
forward power rather than net power. To determine the
power (in Watts) required for any other field strength not
shown, multiply the power required for 1 V/m by the
desired
E
-field squared, or
(
)
(
)
P E
E P
V / m
V / m
=
2
1
To determine the additional amplifier overhead required to
handle 80% amplitude modulation, multiply the result by
3.24 (1.8
2
). Actual transmitted field strength should be
verified using an ETS-Lindgren Model 7200 series electric
field probe or equivalent. Figures 14 and 15 show power
requirements for the lower frequencies at 3 meters based on
measurements using a field probe on an OATS over both
conducting ground and a (2.4m)
2
ferrite absorber field over
conducting ground. For IEC 1000-4-3 type testing, the
antenna tip can be placed at any distance between 1 and 3
meters from the EUT as long as the front face plane is
illuminated according to the -0, +6 dB uniform field
specification. In general, closer distances require less
power to create a given field strength.
