file: dipole

Basics of the most definable dipole defined by three parameters -

Model as unipole sticking through ground plane. Unipole has diameter d, height h, and passes, without changing diameter, through the ground plane into a cylinder of radius D which becomes the outer conductor of a coaxial feedline. The impedance of the antenna can be measured at a point below the ground plane and then transformed to define its nominal value at the ground plane.

Questions:

1. Find the electric field distribution

2. What combinations of d,h,and D will match the feedline?

3. How sensitive is the impedance to the base geometery, e.g.

if we were to put a capacitive collar around the base of the antenna, would its effect be simply to shunt the antenna with a capacitive reactance?

4. When dipole is mismatched, does the static field volume grow? (More mismatch usually means more reactance and reactance will store energy).