COMB

COMB, capa_label, type, x, y, xm, ym, alpha, n_cell, body_nr, mat_nr, layer_nr, p1, p2, ... ;

Creates a comb cell for capacitive sensing and electrostatic actuation

Several comb cell library elements can be linked to seismic masses.
Comb cells with the same capa_label are automatically combined to a single capacitance.
Comb cells consist of local conductors which can be linked to voltage ports by the COND command. The first local conductor is always the moving comb, the other local conductors are the fixed combs.
The layouts of comb cells are defined in “comb cell template” files which are stored in the "./CombCellTemplates" folder. The “comb cell template” files contain comb parameters (p1, p2, …), the comb cell layout, the order of local conductors and the calculation schema for capacitances. Arbitrary user defined comb cells can be added to the folder and will be automatically available in the MODELBUILDER at the next program start.

Input Data⚓︎

Parameter	Description
`capa_label`	Capacitance label of the comb cell → Alphanumeric label, has to start with a letter
`type`	→ See comb cell types below
`x`	X-coordinate of the comb cell connecting point
`y`	Y-coordinate of the comb cell connecting point
`xm`	X-coordinate of the center point for circular combs
`ym`	Y-coordinate of the center point for circular combs
`alpha`	Orientation angle of straight comb cells → Ignored for circular combs
`n_cell`	Number of comb cells at the seismic mass
`body_nr`	Reference number of related mass body → If > 0, the primitive is related to the specified mass body
`mat_nr`	Reference number of the material properties → Use existing material properties only (see MATP command)
`layer_nr`	Layer number (the current version supports only one layer) → If empty, the primitive is part of the first layer
`p1`	First comb cell parameter
`p2`	Second comb cell parameter
`...`	Additional comb cell parameters

The following combs are developed for demonstration. Arbitrary User defined comb cells can be added to the comb library of the MODELBUILDER:

Capa Label	description
`AREAasymf`	Comb area variation (with outer fingers at anchor)
`AREAasymf_noanchor`	Comb area variation (with inner fingers at anchor)
`AREAinnerf`	Comb area variation (with outer fingers, no anchor)
`AREAouterf`	Comb area variation (with inner fingers, no anchor)
`AREAouterf_noanchor`	Comb area variation (asymmetric fingers, no anchor)
`AREArecess_asym`	Differential comb with two fixed conductors
`AREArecess_lower`	Differential comb with two fixed conductors (flipped anchor position)
`DIF1double`	Differential comb with two fixed conductors (no anchor extrusion)
`DIF1double_nof`	Differential comb with two fixed conductors (flipped anchor, no extrusion)
`DIF1single`	Differential comb cell with one fixed conductor
`DIF1single_nof`	Differential comb cell with one fixed conductor
`DIF2double`	Differential comb cell with one fixed conductor
`DIF2double_nof`	Differential comb cell with one fixed conductor
`DIF2single`	Differential comb cell with one fixed conductor
`DIF2single_nof`	Differential comb cell with one fixed conductor

Mirrored comb cells are automatically generated by i-ROM Sketcher under the name comb_label.flip. Manual placement of these mirrored variants is not required.
The capacitance fitting function samples all degrees of freedom with high precision by default, which may result in longer simulation times. The sampling resolution can be reduced if full accuracy across all degrees of freedom is not necessary; however, this may affect the quality of the results.
To modify comb cell templates, copy the corresponding library element into the project’s local working directory. Local elements take precedence during project loading and will override the default template.
Requests for additional comb cell variants or modifications to existing templates may be submitted at any time and with any license level to support@i-rom.de. A sketch of the required comb cells should be included with the request.