|
|
|
Foundation ::
Antenna Design and Satellite Communications ::
DUALREF
|
DUALREF
Generalized Dual Reflector Analysis Computer Program
|
 |
|
SOURCE CODE AVAILABLE
|
|
DUALREF provides accurate prediction of radiation characteristics for microwave antennas. Antenna radiation characteristics such as beamwidth, gain, aperture efficiency, side-lobe level, and cross polarization are used in analyzing and designing advanced antenna systems. While the single offset paraboloid has been the most extensively used configuration for the satellite multiple-beam antenna, the trend toward large apertures requiring minimum scanned beam degradation over the field of view (18 degrees for full earth coverage from geostationary orbit), may lead to an impractically long focal length and large feed arrays. On the other hand, dual reflector antennas offer packaging advantages and more degrees of design freedom to improve beam scanning and cross-polarization properties. Reflector antennas are widely used in communication satellite systems because they provide high gain at low cost. The Cassegrain and Gregorian antennas are the most commonly used dual reflector antennas. DUALREF can calculate the secondary pattern and directivity of both these antennas and any similar generalized dual reflector antenna system.
DUALREF uses the physical optics-current methodology for describing the induced currents on the sub and main reflector. The resulting induced currents on the
main reflector satisfy Maxwell's equations, so they are integrated to obtain the antenna far-zone electric fields. The program output describes antenna radiation
characteristics such as beamwidth, gain, aperture efficiency, side-lobe level, and cross polarization. This computer program has been verified with other physical
optics programs and with measured antenna patterns, and the comparison shows good agreement in far-field sidelobe reproduction and directivity.
DUALREF is written in Microsoft Fortran PowerStation for IBM PC compatibles running Windows 3.1, Windows 95 or Windows NT. Microsoft Fortran
PowerStation for Windows and a plotting program (e.g. MATLAB or Mathcad 5.0 Plus) are required. DUALREF has been successfully implemented on an IBM
PC compatible 486DX/33 running Windows 95.
DUALREF carries the NASA Case Number LEW-16226. It was originally released as part of the NASA COSMIC collection.
|
|
More software from National Technology Transfer Center
|
|
|
|
|
|
