A novel method of calculating farfield patterns of large aperture antennas
Abstract
A method is described for calculation of the radiation pattern of large aperture antennas. A piecewise linear approximation of the aperture field using overlapping pyramidal basis functions allows the radiation pattern of an aperture antenna to be calculated as though it were a twodimensional array. The calculation of radiation pattern data versus theta and phi, suitable for 3D or contour plot algorithms, is achieved by locating the array in the yzplane and performing a summation over the aperture field data sampled on a square grid. A FORTRAN subroutine is provided for performing radiation pattern calculations. Numerical results are included to demonstrate the accuracy and convergence of the method. These numerical results indicate that typical accuracies of + or  0.1 dB for Directivity, + or  dB for the 1st Sidelobe Level, and +  2dB for the 2nd Sidelobe Level can be obtained with an aperture grid of 45x45 points and requires approximately 0.02 seconds CPU time per farfield data point on a VAX 11/750 with a floating point accelerator.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 March 1986
 Bibcode:
 1986STIN...8622783B
 Keywords:

 Antenna Radiation Patterns;
 Apertures;
 Approximation;
 Far Fields;
 Linear Systems;
 Numerical Analysis;
 Sidelobes;
 Computer Programs;
 Floating Point Arithmetic;
 Fortran;
 Subroutines;
 Vax Computers;
 Communications and Radar