Technical Info

In the definition and specification of antennas, many terms are used. SCAN Antenna product sheets use the following definitions:

Gain:

Antenna gain is specified using dBd, dBi or dBic.

dBd : dB relative to a Dipole antenna

dBi : dB relative to an isotropic radiator, always 2.1 dB higher than the dBd gain.

dBic : same as dBi, but referring to circular polarisation

Radiation patterns shown are always the vertical pattern (elevation). Horizontal (azimuth) patterns are often perfect circles for omnidirectional antennas. Example of radiation pattern for a vertical dipole, showing 2.1 dBi peak gain:

 

VSWR:

VSWR (Voltage Standing Wave Ratio), is a measure of how well the antenna is matched to 50 ohms at different frequencies. VSWR 1.0:1 is a perfect match.
VSWR plots are available on some antennas. Plots show the VSWR limit (dashed line) in the specified frequency band (grey block).

General technical information relating to antennas :

Wikipedia page on Antennas

Wikipedia page on dB (decibel)

Wikipedia page on the Electromagnetic Spectrum

Wikipedia page on GSM Frequency Bands

Wikipedia page on UMTS/3G Frequency Bands

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