DSC02784

17    From thc Objects to extrude list select RI.

18    In the Distance edit field enter -10e -6.

19    Click OK.

Extruding the geometry to create the Silicon substrate below the combs.

PHYSICS SETTINGS

Boundary Conditions

Start defining the physics settings by giving the boundary conditions. The first comb is ticd to ground, and the second is defined as a port. You model the surrounding boundaries with the symmetry condition.

1    From the Physics menu choose Boundary Settings.

2    On the Condition page select the following values:

PARAMETERS	VALUE ON BOUNDARY
	1-5,7, 12, 13,52,53	8-1 i, 14-27,42-46	28-41,47-51
Boundary	Zero charge/	Ground	Port
condition	Symmetry

3    While still in thc Boundary Settings dialog box select one of the port boundaries and select the Select by group check box. Doing so selects all port boundaries. Thcn click thc Port tab.

4    On the Port tab verify that the port number is 1. Then select thc Use port as input check box, and from the Input Property list select Energy method. Using thcsc settings ensurc that a unit voltage is forced on the boundaries of thc sccond comb drive, and thc capacitancc value is integrated from electric cnergy dcnsity.

48 I CHARTER 2: MEMS ACTUATOR MODELS