ETS-Lindgren BiConiLog 3149, User Manual, Page: 7 / 33

Introduction
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7
1.0 Introduction
The
ETS-Lindgren
Model 3149 BiConiLog™
is a
dual-purpose antenna that can
be used for both emissions
and immunity applications. The
Model 3149 is a hybrid linearly
polarized EMC antenna
consisting of a log periodic
dipole array (LPDA) and a
single bow tie antenna.
The Model 3149 has an ultra broadband frequency range, accepts high power
input, and is size-efficient for easy transport and use in compact chambers.
Rugged construction assures dimensional and electrical stability over extended
use.
The BiConiLog antenna combines the best characteristics of biconical and log
periodic antennas, sweeping over a wide frequency range and making it ideal for
automated testing. The 80 MHz to 5 GHz frequency range of the Model 3149 is
the broadest and highest of all BiConiLog antennas and most commercially
available antennas of this type.
The Model 3149 accepts up to 800 W of peak power input at the lower
frequencies of operation. The high gain and low VSWR over the operating
frequency range translate into efficient amplifier use for field generation. The
Model 3149 differs from most biconical and log periodic hybrids with relatively
low VSWR at the lower frequencies of operation, allowing about half the power to
be radiated by the antenna.
Antenna performance can be degraded by cross polarization of horizontal and
vertical signals. In high frequency log periodic antennas where elements are
small and closely spaced, cross polarization can be difficult to avoid. The high
frequency section of the Model 3149 was modeled and precision manufactured
to avoid this problem. Cross polarization rejection in the Model 3149 exceeds
20 dB, making this antenna one of the few antennas that are compliant for
CISPR16-1 measurements.