Source Code Description: Subroutine GFF

GFF

PURPOSE: to calculate the far-zone field of a sinusoidal electric monopole.

METHOD: If an electric line source has length d and endpoints at (x₁, y₁, z₁) and (x₂, y₂, z₂), then the coordinates of any point on the source are

where cos(x), cos(y), cos(z) are the direction cosines of the l axis, and l is the distance along the source measured from the endpoint (x₁, y₁, z₁). Let the current distribution on the monopole be:

Where I₁ and I₂ are the endpoint currents. The far-zone field of this source is:

where

and are the spherical coordinates of the observation point.

In this subroutine the range dependence has been suppressed. The far field vanishes in the endfire direction where GK=0. If a ground plane is present (IGRD > 0) the E₁ equation above is decomposed into the x, y, and z components and the reflection coefficients are applied before E_q and E_f field components are returned to the calling program.

CALLED BY:

• GFFLD

CALLS TO: NONE