Using HFSS to simulate a mono-pole antenna

Hi everybody,

I try to use the HFSS to simulate a mono-pole antenna, but how can i defind the finite ground plane for the mono-pole antenna ?
I only defind the plane as copper so that the 3D pattern that i get is same as the diple one which is not what i expect.

Thanks for helping.

I will assume you are tallking about a monopole over a perpendicular
ground plane. In this case if the size of the ground plane is not big
enough some of the energy will be radiated toward the back of
the ground plane. One solution is using a bigger plane which in turn
will increase the size of the model and the simulation time . The
other solution is use a moderate ground plane and click in the option
"infinite" ground plane in HFSS. What this does is not consider the
fields(electrical and magnetic) at the edges of the ground plane, they
will behave as it were an infinite ground plane. The solution is closer
to reality.

Thanks jallem,

you are right, i am simulating a monopole over a perpendicular ground plane. If my monopole is a cyclinder with 1mm diameter, 4 cm long, and the perpendicular plane is 10cm X 10cm, is it larg enough?

What i worry is, i just assign boundary of the perpendicular plane as a finite conductivity (copper), and then draw a coaxial which outer conductor which is connected to the plane and the inner conductor is connected to the monopole, and then excite it by a lump port, without telling the HFSS that my perpendicular ground plane is a finite ground plane, it seems the 3d pattern always assume my perpendicular plance as radiator.

I don't want to assign the plane as infinite ground plane. Just assume i have any shape of metal plane, how can i assign the boundary and excitation so that HFSS know it is a ground plane?

Thanks for helping.

Kevin, I modeled your monopole and you are right, the
pattern looks just like there is not ground plane. But, I think the problem here is the definition. I used a surface (rectangle) as a ground plane and nothing underneath of it. The current distribution along this surface will radiate in both directions upper and lower of the ground level. I think the solution would be to use a thicker ground plane.

Thanks jallem,

you have mention "nothing underneath of it".....do you mean that the air box do not include the plane?
I am no so understand why thicker plane can help?