9
INTRODUCTION
ETS-Lindgren Model 3127 Resonant Loop Antennas are magnetic dipole antennas designed to meet the Cellular
Telecommunication and Internet Association’s (CTIA) +/- 0.1 dB symmetry requirement for ripple test measurements
at the labeled center frequency. These omni-directional antennas have a magnetic dipole pattern approaching that of
a half wave resonant electric dipole. The pattern produced has the same peak and null orientation as that of a sleeve
dipole oriented along the same axis, but with the directions of the electric and magnetic elds reversed. That is, the
electric eld vector along the azimuth is perpendicular to the axis and the magnetic eld vector is parallel to the axis.
The loop design allows the antenna to be end-fed to avoid cable and feed-point interactions that interfere with the
symmetry of the antenna. Integral quarter-wave chokes and/or ferrite loading (depending on frequency range) also help
to reduce cable interaction. This design also provides exceptional symmetry to meet the CTIA criteria for ripple test
antennas.
All Model 3127 antennas are designed with better than +/- 0.1 dB symmetry (0.2 dB peak-to-null) in at least a +/- 5 MHz
band around the labeled center frequency. For reference purposes, gain and symmetry values are provided for a 10
MHz band, depending on model, centered about the labeled frequency. The loops have nominal 50 ohm impedance, a
maximum continuous transmit power of one watt, and are equipped with a female SMA connector.
The loops are calibrated using an A2LA accredited process with a typical measurement uncertainty on the order
of +/- 1.0 dB at the center frequency. During the calibration process, the dipoles are also certied to meet ± 0.1 dB
symmetry required for use in the ripple test specied in the CTIA’s Over-The-Air Performance Test Plan, in a +/- 5
MHz band around the labeled center frequency. Maximum ripple, VSWR, and approximate gain values are provided
with each calibration. Note that the gain values provided with this calibration are for diagnostic reference purposes
only. For accurate gain values to perform range calibration, the Model 3126 Precision Reference Sleeve Dipoles are
recommended. Individual calibration data is included with each dipole. Gain value is not provided with the 3127-3600
and 3127-5500 Loops. Any gain data provided for any 3127 loop is for reference only.
The Model 3127 antenna family covers a range of frequencies intended for characterization of wireless chambers
including, but not limited to, the following models:
3127-450 3127-1575 3127-2132
3127-617 3127-1732 3127-2140
3127-700 3127-1747 3127-2450
3127-722 3127-1768 3127-2535
3127-836 3127-1800 3127-2655
3127-880 3127-1868 3127-3600
3127-897 3127-1880 3127-5500
3127-920 3127-1950
The digits following the hyphen in the model name note the center frequency of the antenna. For example, Model
3127 450 has a center frequency of 450 MHz. This manual applies to the frequencies listed, as well as any custom
frequencies.
Standard Conguration
• Model 3127 antenna
• A2LA accredited precision calibration and symmetry certication included signed certicate of calibration
