After constructing a solid object, right click on Vacuum -> Properties. Now, you can see a list of materials in this window. You can select the desired one. If you wish to create your own material, you can click on the "Add Material" button, change the Material Name and it Properties. It is that simple!
After creating an object, right click and go to add materials, then put in the specific values of the asked parameters. You are required to take into account the material properties such as permittivity, permeability and loss tangent. All these values will effect the reflection of the designed antenna,
I have designed a compact quadband coplanar fed monopole antenna and simulated it. After simulating it i want to make some more modifications and in that process i am trying to add some more rectangles to it. It is displaying non model objects. what can i do to add to the model..........
loss tangent, permitivity and permeability are the most important for any material u consider. So, try to come to an opinion of which material to use according to ur research need. And adding that material can be done, as explained by above respected researchers.