What's wrong simulation in CST changing material

[noisepic]

I try simulate VHF antenna (Yagi) with changing differient material : Steel, Aluminum, Iron but All results the same (Gain, E-field).
I wonder what's wrong with my simulation? And how to simulate to see different material lead to differ Antenna's characteristic.

I'm using CST.

Tks

 

[Eng.Wad]

Have you set your boundary conditions and background properties?

 

[jeeudr]

Steel, Aluminium and Iron are all very good conductors. There is very little difference to be expected when changing between these materials.

In patch antennas (or similar) with a substrate, the properties of the substrate material can greatly affect performance of the antenna.

But, for a simple Yagi made of only metal, you do not expect much difference and you are better off simulating with just a PEC.