3127 Magnetic Dipole Antenna

ETS-Lindgren's Series 3127 Resonant Loops are 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 omnidirectional 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 fields reversed. That is, the electric field vector along the azimuth is perpendicular to the axis and the magnetic field vector is parallel to the axis. The loop design allows the antenna to be end-fed to avoid cable and feedpoint 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 3127 resonant loops 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. VSWR is less than 5:1 at the resonant frequency, which is slightly higher than the labeled symmetry frequency. For reference purposes, gain and symmetry values are provided for a 200-300 MHz band (depending on model) centered about the labeled frequency. The loops have a nominal 50 Ω 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 certified to meet the +/- 0.1 dB symmetry required for use in the ripple test specified 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 is for diagnostic reference purposes only. For accurate gain values to perform range calibration, the ETS-Lindgren Model 3126 Precision Reference Sleeve Dipoles are recommended.