cannot find copper material from the material library

hello,
i am designing half-disc patch antenna.the problem is i can't find copper material from the material library for the ground and the patches. iam using Roger rt5800 lossy as the substrate..there's only sse-copper, copper (annehealing) in the ,library..do i need to declare new material?if so, how?

Which software are you using?
you can Google the properties and characteristics of Roger-rt5800 like dielectric constant, loss tangent etc and can insert these values in your own declared library.

cst microwave...oh ok..does PEC is same with copper?i mean in terms of its characteristics

I don't understand what you are asking what does PEC stands for?

No, different. PEC = perfect conductor (lossless)

Copper has conductivity 5.8e7 S/m. The thickness of your RT5880 copper can have different values, so you need to check what copper thickness you have. There are two different surfaces (rough electrodeposited copper and smooth rolled copper), but you can ignore that different at the moment.

Once you have created a structure Go to material, right click and clcik New Material option.
or
While drawing also you can create a new material.

you should use the load from material library option when you are building the objects and then set the check box as titled by use filter, type copp, next you can see the copper material.