On the Radiation Patterns of Common EMC Antennas
Antennas have been used in EMC
measurements since the early days.
Knowledge of the antenna pattern
was not a requirement of the standards.
While MIL STD 461 and some SAE standards
called for information on the half
power beamwidth, most standards did not
require any knowledge of the antenna radiation
characteristics. With the evolution of
standards to cover frequencies above 1 GHz
knowledge of the pattern has become more
important. Since above 1 GHz most antennas
are very directive and very un-dipole-like,
information on the pattern has become very
important, especially when it comes to understanding
how much area the main beam
is covering. The present paper starts by giving
the reader a refresher on antenna pattern
parameters and then shows typical patterns
for the most common antennas used in EMC.
The antennas covered are biconicals, log
periodic dipole arrays, hybrid antennas and
dual ridge horns. Measured data is presented
except for patterns above 18 GHz.