But that formula for z does not appear to be correct!
Art
"Richard Clark" wrote in message
...
On Sat, 12 Mar 2005 00:38:31 GMT, "
wrote:
The formula for z which you gave would give me nightmares.

Hi Art,

That is the Cartesian form. A 2D polar form would follow:

I = I0 · A · cos (phi) · cos (theta) / Pi
where
I is the intensity at a point with elevation theta
A is the area of the surface
I0 is the radiation directed normal to a diffuse surface
phi is the angle of incidence (all angles being considered)

A variant for conforming radiators is found in:

I = I0 · cos (theta)

Observation will reveal why this is called Lambert's Cosine Law.
Simple draughting techniques will reveal the circular distribution
curve.

A simple example of the last equation is found in the common, unlensed
LED. Insofar as radios go, I expect the same response would follow
from placing an isotropic source above a diffuse reflector (you would
then have to use the first equation).

73's
Richard Clark, KB7QHC