PCAP

PCAP, pcap_name, capa_label, type, b_opt, target_body, ref_nr, layer_nr, p1, p2, p3, ... , pn, orient_ang, fill_fact;

Creates a primitive for a parallel plate capacitor

Parallel plate capacitors are assembled from several primitives (rect, circ, elps, tria, poly) defined by the type-parameter.
Boolean operations are applied to all elements in the same group. Group elements have the same target_body number, ref_nr and layer_nr. The capa_label of all group elements must be the same.
If the capa_label of different groups is the same, capacitances are combined to a single capacitance value.
The target_body number refers to the mass body reference number of the moving conductor.
The ref_nr is used to create individual capacitances acting in the same target_body number and layer_nr.
The layer_nr is used to calculate the electrode gap to moving mass bodies at the initial position (see LAYR command).
Parallel plate primitives consider out-of-plane and in-plane motion components. The capacitance change of in-plane motion components is linearized at the initial position. The influence of perforations holes (see PERF command) is taken into account but fringing fields in holes and outside the plate area are ignored.
Perforations holes reduce the plate area and associated capacitances. An area fill factor fill_fact can be used to scale the capacitances of the primitive. Area fill factors less than one are commonly used to defined an effective area in models where the perforations are ignored. Alternatively, area fill factors greater than one are used to account for the influence of fringing fields in perforation holes, which increases the capacitances.

Input Data⚓︎

Parameter	Description
`pcap_name`	Reference name of the parallel plate primitive → Alphanumeric name, has to start with a letter
`capa_label`	Capacitance label of the parallel plate primitive → Alphanumeric label, has to start with a letter
`type`	Type of the parallel plate element (primitive) Available types: → `rect` = Rectangular primitive → `circ` = Circular primitive → `elps` = Elliptical primitive → `tria` = Triangular primitive → `poly` = Polygonal primitive
`b_opt`	Type of the Boolean operation → `add` - Add the area of the primitive to a capacitance → `sub` - Subtract the area of the primitive from a capacitance
`target_body`	Target mass body number to define the moving conductor → Integer > 0, related to the specified mass body
`ref_nr`	Reference number to create different capacitances on the same target mass and the same layer → Integer > 0
`layer_nr`	Layer reference number to define the electrode gap → Integer > 1, related to the specified layer

type = rect (see RECT command)

Parameter	Description
`p1`	X-coordinate of the connecting point for rectangular primitives
`p2`	Y-coordinate of the connecting point for rectangular primitives
`p3`	Length (x-direction) of the rectangular primitive (can be negative)
`p4`	Height (y-direction) of the rectangular primitive (can be negative)
`orient_ang`	Orientation angle in degrees at the connecting point: 0 ≤ `orient_ang` ≤ 360
`fill_fact`	Area fill factor of the primitive → > 0, Default = 1

type = circ (see CIRC command)

Parameter	Description
`p1`	X-coordinate of the center point (connecting point)
`p2`	Y-coordinate of the center point (connecting point)
`p3`	First radius of circular primitive
`p4`	Second radius of circular primitive → If empty or `p4`=0, it defines a solid circle
`p5`	Starting angle of the circular segment: 0 ≤ phi1 < 360
`p6`	Span angle of the circular segment: 0 < phi2 ≤ 360
`orient_ang`	Orientation angle in degrees at the connecting point: 0 ≤ `orient_ang` < 360
`fill_fact`	Area fill factor of the primitive → > 0, Default = 1

type = elps (see ELPS command)

Parameter	Description
`p1`	X-coordinate of the center point (connecting point)
`p2`	Y-coordinate of the center point (connecting point)
`p3`	Radius in x-direction of the non-rotated ellipse
`p4`	Radius in y-direction of the non-rotated ellipse
`p5`	Starting angle of the circular segment: 0 ≤ phi1 < 360
`p6`	Span angle of the circular segment: 0 < phi1 ≤ 360
`orient_ang`	Orientation angle in degrees at the connecting point: 0 ≤ `orient_ang` < 360
`fill_fact`	Area fill factor of the primitive → > 0, Default = 1

type = tria (see TRIA command)

Parameter	Description
`p1`	X-coordinate of the first point (connecting point)
`p2`	Y-coordinate of the first point (connecting point)
`p3`	Second x-coordinate of the primitive
`p4`	Second y-coordinate of the primitive
`p5`	Third x-coordinate of the primitive
`p6`	Third y-coordinate of the primitive
`orient_ang`	Orientation angle in degrees at the connecting point: 0 ≤ `orient_ang` ≤ 360
`fill_fact`	Area fill factor of the primitive → > 0, Default = 1

type = poly (see POLY command)

Parameter	Description
`p1`	Total number of polygon points
`p2`	X-coordinate of the first point (connecting point)
`p3`	Y-coordinate of the first point (connecting point)
`p4`	Second x-coordinate of the primitive
`p5`	Second y-coordinate of the primitive
…, `pn`	Further pairs of x-y-coordinates
`orient_ang`	Orientation angle in degrees at the connecting point: 0 ≤ `orient_ang` < 360
`fill_fact`	Area fill factor of the primitive → > 0, Default = 1

The following figure shows an example where different reference numbers (ref_nr) are necessary for modeling of bottom plate capacitors.

The micromirrors consist of two mass bodies, the inner mirror mass with body reference number 1 and the outer actuation mass with body number 2.

The upper drive capacitor (drive+) acts on mass body 2 (target mass) and is placed in layer 2. The lower drive capacitor (drive-) acts on the same mass body and is placed in the same layer. Each capacitor is modeled by a rectangular primitive and a circular cut.

In the lower figures, the circular cuts are shifted to the left and to the right to demonstrate that Boolean operations are only applied to primitives in the same group.

Figure 1. Parallel plate capacitors with different reference numbers