STK Antenna Models

Cosine Squared Aperture Rectangular Antenna

Cosine squared curve distribution pattern, with a rectangular pattern of illumination, illustrated by the blue curve below.

This antenna uses a rectangular coordinate system.

Parameter Description
X/Y Dimension

The X Dimension and Y Dimension of the antenna gain pattern. Valid if Use Dimensions is selected. The beamwidths will be automatically calculated and displayed.

X/Y Dim Beamwidth The X Dim Beamwidth and Y Dim Beamwidth of the antenna gain pattern. Valid if Use Beamwidth is selected. The dimensions will be automatically calculated and displayed.
Design Frequency

Read-only field that displays the frequency inherited from the antenna's parent object (receiver, transmitter or radar), which is used in deriving 3dB beamwidth(s) from diameter or dimensions and vice versa. Frequency value must be changed before opening the details panel in order to be used for gain calculation.

For a communications receiver or transmitter, Design Frequency is set in the Single Beam Antenna window or, in the case of multibeam models, in the Modify Antenna Beam window. For a radar, it is set on the System page under Basic properties. A default value is used for retransmitters.

Main-lobe Gain The main-lobe gain value. Valid if Computed is not selected. Select Computed to automatically calculate the main-lobe gain based on beamwidth or diameter, efficiency, and design frequency.
Efficiency The antenna efficiency factor, ranging from 0 to 100 percent.
Back-lobe Gain Back-lobe gain can be used two different ways:
  1. A constant gain value from 90 to 270 degrees in elevation from the boresight of the antenna.
  2. Modeled as a fraction of the Main-lobe Gain, but in the opposite direction. For example, boresight gain is computed at a 0 degree elevation angle, the back-lobe attenuation factor is applied and the result is used as the gain at the 180 degree elevation angle. The backlobe gain is a mirror image of the forward gain, but with the backlobe gain applied as an attenuation factor. If “Use as main-lobe attenuation” is selected, the attenuation factor is applied on the main-lobe gain and the result is used in the back-lobe direction.