The Monopole
The same as classical dipole cut in half and mounted vertically over a reflective ground plane.
As usual all results: AS IS, no responsibility assumed.
A Monopole Diagram
Note:
The length for analysis is limited to the most common values 0.125 lambda to 1.0 lambda. Above 0.625 lambda the radiation will begin to lobe out.
The reflective plane is assumed to be infinite. If < 5 lamda radius of the antenna the radiation pattern will incline upwards.