Thick Metal Model
The Thick Metal Model metal type allows you to model physically thick planar metal. By default, the Normal metal type is modeled as having zero thickness where the entered thickness value only affects the calculated loss. The Thick Metal model allows you to insert physically thick metal in your circuit. Using a thick metal type not only allows for proper modeling of loss, but also includes the EM effects of physical thick metal, such as coupling between closely spaced conductors.
You define thick metal using four input fields: metal thickness, the number of sheets used in the model, the direction the metal extends and a fourth field you choose by selecting an entry from the Specify Using drop list. These four values are used to determine the frequency dependent surface impedance of the metal.
Specify Using: You may choose to define your metal loss using Conductivity, Resistivity, or Sheet Resistance at DC. Select which value you wish to use from this drop list. The dialog box is updated to include a text entry box for whichever choice you make in the drop list.
Thickness: The metal thickness defines the overall physical thickness of the metal. The units of the thickness are your project units.
Number of Sheets: The number of sheets determines how many levels of metal you wish to use in modeling the thick metal. As you increase the number of sheets the accuracy of your answer is improved. However, there is a trade off since an increased number of sheets also demands more processing time and memory use. The recommended default of two sheets should prove to be adequate for most circuits.
Direction: Select "Up" from this drop list if you wish the Thick metal to extend upward through the dielectric layer from the level on which the polygon is drawn. If you wish to have the metal extend downward into the dielectric layer underneath the metal level, select "Down" from this drop list. Extending upward is the default.