Top Metal, Bottom Metal

These drop lists allow you to select the metal type for the box top and box bottom. You can choose either a predefined metal type or user defined Sonnet material. You may not use a material that is defined using the thick metal model for a box top or bottom. For details on defining a new material and their parameters, see Sonnet Dielectrics.

There are three predefined metal types available in Sonnet:

•    Lossless, models a perfect conductor
•    WG Load, models a perfect matched waveguide load.
•    Free Space, which removes the top or bottom cover.

WG Load is useful for modeling infinite arrays. The top or bottom cover is terminated with a perfectly matched waveguide load. Note this is not the same as an open environment. To model an open environment select Free Space, which sets the impedance of the cover to 377 ohms/sq, the impedance of free space. Note that the sidewalls are always modeled as perfect conductors.