wiki:Manual/DataTypes/Antennas

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Antenna

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Dialog window

This function is used to describe the radiation patterns of antennas. In the scenario definition windows, each transmitter and receiver of both victim and interfering links has an "Antenna Patterns Identification" panel, which allows you to define antenna parameters. The positioning of the antennas and its pointing convention in a scenario is described in a separate section:

By default all antennas have 0 dBi gain and are non-directional, i.e. not having any directivity patterns associated. Depending on the type of transceiver antenna to be described in the scenario, you may define it by modifying the antenna gain and activating one or more of radiation patterns (e.g. you may feel it sufficient to activate horizontal pattern, but if the vertical discrimination is important, both vertical and horizontal patterns could be activated as well, more info on the calculation of the antenna gain at the end of this page):

  • Library: you are able to either import () from the library an antenna pattern or you can export () your own antenna pattern to the library (more information on antenna library).
  • Name: It is unik and help you to find your entries in the library.
  • Description: It is recommended that you write down some information about your antenna.
  • Antenna Peak Gain: describes peak antenna gain, i.e. gain in the direction of maximum radiation (main lobe), defined in dBi.
  • Horizontal pattern: describes the antenna radiation pattern in horizontal plane, defined by pairs (φ, gH(φ)), where φ (deg, range 0...+360) describes the angular offset in horizontal plane with relation to the direction of maximum radiation, and gH(φ) describes the relative gain, related to the antenna maximum peak gain. Note that gH(φ) values should be negative. (more information on antenna pointing convention).
  • Vertical pattern: describes the antenna radiation pattern in vertical plane, defined by pairs (θ, gV(θ)), where θ (deg, range -90...+90) describes the angular offset in vertical plane with relation to the direction of maximum radiation, and gV(θ) describes the relative gain, related to the antenna maximum peak gain. Note that gV(θ) values should be negative (more information on antenna pointing convention).
  • Spherical pattern: describes the antenna spherical radiation pattern, defined by pairs (Φ, gS(Φ)), where Φ (deg, range 0...+180) describes the spherical angle, and gS(Φ) describes the relative gain, related to the antenna maximum peak gain. Note that gS(Φ) values should be negative.

Defining antenna pattern

To define the antenna patterns, the dialog window is similar to those used to enter the function dialog windows. However the important difference is that antenna pattern dialog windows do not allow to set Constant parameters, and they have two displays to present the entered data - the usual XY plane, and the Polar display. These are illustrated by two respective pictures below.


Defining antenna pattern, using XY coordinates system


Defining antenna pattern, using Polar coordinates system

Antenna pattern convention

Horizontal antenna pattern angle definition Vertical antenna pattern angle definition Spherical antenna pattern angle definition
positive = counter-clockwise to the 0 deg referencepositive = counter-clockwise to the 0 deg referencepositive = counter-clockwise to the 0 deg reference

Calculation of antenna gain

It is assumed that the frequency has no impact on antenna efficiency/gain, therefore antenna gains are calculated based on pure peak gain combined with necessary angular discrimination in case of directional antennas (i.e. antennas having radiation patterns assigned in the scenario).

The calculation of the antenna gain for a path between transceiver trx1 and transceiver trx2 is performed as follows.

Case A: If no spherical antenna pattern is defined:

  • Gain in horizontal plane: if horizontal antenna pattern is defined, then
  • Gain in vertical plane: if vertical antenna pattern is defined, then:
  • When the two antenna patterns (horizontal and vertical) are selected, SEAMCAT calculates the resulting antenna gain as a pseudo 3-D antenna gain . The calculation is based on the following approximation with a treshold value of 3 dB:

Case B: If spherical antenna pattern is defined:

  • The spherical-angle gain is calculated:
  • Total gain is then calculated as follows:

Antenna pointing convention

SEAMCAT gives you the freedom to set the antenna pointing of your element as you want. For example you can do beamforming tracking (e.g. Airplane). The antenna pointing is only set for either the victim link or the interfering links.

The usage of the antenna pointing panel is as follow:


Explanation of the antenna pointing panel

Azimuth angle: A positive value is equivalent to counter-clockwise to the 0 deg reference


Azimuth angle convention

Elevation angle: A positive value is equivalent to counter-clockwise to the 0 deg reference


Elevation angle convention

Attachments