A question about polarization

Re:
> *proper* definitions of the radiation pattern parameters in the
> output of NEC.

The z axis is considered vertical in NEC, so theta is measured from the
z axis, and phi from the x axis in the horizontal plane. E(THETA) and
E(PHI) are the components of electric field along the theta and phi unit
vectors. If no range R is specified on the RP command they are
components of E divided by Exp(-j k R)/R in units of volts, while if R
is specified they are the electric field in volts/m at a distance R.
These are labeled correctly in NEC-4, but in NEC-2 they are always
labeled as volts/m, even when they are really volts.

The definition of gain is given on pages 286 through 289 of the NEC-2
Code manual. The total gain involving [\vec{E} . Conjugate(\vec{E})]
is just the sum of the component gains G_u=const*[E_u * Conjugate(E_u)]
and G_v=const*[E_v * Conjugate(E_v)] when u and v are orthogonal unit
vectors, vertical and horizontal or major axis and minor axis. The
terms vertical gain and horizontal gain refer to the theta and phi
components of field, respectively. The tilt angle of the polarization
ellipse is measured from the theta unit vector to the major axis of the
ellipse in a right-hand sense for an outward propagating wave, and
"SENSE" of the rotation is right or left for the outward wave.

Jerry Burke
LLNL
Received on Fri Dec 08 1995 - 03:38:00 EST