MODEL 3148 LOG-PERIODIC DIPOLE ARRAY ANTENNA
Introduction
© EMC TEST SYSTEMS, L.P. – SEPTEMBER 2002
1
REV C – PN 399239
INTRODUCTION
The ETS-Lindgren Model 3148 Log Periodic Dipole Array is a
linearly polarized, broadband antenna designed to operate over the
frequency range of 200 MHz to 2 GHz. The choice of scaling
factors, the various diameters of each element, and the center-to
center spacing of the booms are such that excellent VSWR
characteristics are obtained throughout the operating frequency
range (See Model 3148 VSWR data in the “Typical Data” section
of this manual). The precise design of the feed and positioning of
the elements on the boom yield optimum phase relationship. This
causes the active region, at any given frequency, to propagate RF
energy towards the smaller elements leaving the elements behind it
electrically dead.
The Model 3148 antenna fully satisfies CISPR-16 cross-
polarization rejection requirement, and has better than 20 dB cross-
polarization rejection below 1000 MHz. The constant gain of the
antenna yields an antenna factor which varies linearly with
frequency as shown in the “Typical Data” section of this manual.
The variation is smooth; therefore, accurate interpolation of
performance between specified frequency points is simple.
The Model 3148 Log-Periodic antenna is constructed of
lightweight, corrosion-resistant aluminum, providing years of
trouble-free indoor and outdoor service.
The antenna is provided with an integral mount and the necessary
attachments to mount the antenna to either a tripod (with a ¼-20
threaded mount) or an ETS-Lindgren antenna mast. Individual
antenna calibration data is included with each antenna.
The Model 93148 is a non-characterized version of the Model
3148. Should calibration/characterization be desired please contact
our calibration department.
