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Pair of Coupled Circular Wire Solenoids: CSOLIND

Symbol

Summary

This circuit component models a pair of electromagnetically coupled circular solenoids (optionally tapered) made of the wire of a cylindrical cross-section and situated above infinite perfectly conducting ground. The modeling approach is based on evaluation of self and mutual inductances, capacitances, and resistances between all spiral turns.

Topology

Parameters

Name Description Unit Type Default
ID Element ID Text IND1
NT1 Number of turns of solenoid #1 (>=1)   5
NT2 Number of turns of solenoid #2(>=1)   5
Dia Wire diameter Length 25 um
DS1 Start diameter of solenoid #1 (measured between wire centerlines) Length 500 um
DS2 Start diameter of solenoid #2 (measured between wire centerlines) Length 500 um
DE1 End diameter of solenoid #1(measured between wire centerlines) Length 250 um
DE2 End diameter of solenoid #2 (measured between wire centerlines) Length 250 um
PS1 Pitch of solenoid #1 (measured between wire centerlines along solenoid axis) Length 80 um
PS2 Pitch of solenoid #2 (measured between wire centerlines along solenoid axis) Length 80 um
H1 Elevation of solenoid #1 above ground Length 300 um
H2 Elevation of solenoid #2 above ground Length 300 um
X2 X-position of solenoid #2 relative to solenoid #1 Length 1500 um
Y2 Y-position of solenoid #2 relative to solenoid #1 Length 0 um
RotX1 Solenoid #1 angle of rotation about local X-axis Degrees 0
RotX2 Solenoid #2 angle of rotation about local X-axis Degrees 0
RotY1 Solenoid #1 angle of rotation about local Y-axis Degrees 0
RotY2 Solenoid #2 angle of rotation about local Y-axis Degrees 0
RotZ1 Solenoid #1 angle of rotation about local Z-axis Degrees 0
RotZ2 Solenoid #2 angle of rotation about local Z-axis Degrees 0
*Nts1 Solenoid #1 number of linear segments per turn   8
*Nts2 Solenoid #2 number of linear segments per turn   8
Rho Wire metal bulk resistivity relative to gold   1
*Er Relative dielectric constant of encasing material   1
*Tand Loss tangent of encasing material   0

* indicates a secondary parameter

Parameter Details

NT1, NT2 The numbers of spiral turns forming solenoids.

Dia. The diameter of solenoid wire.

DS1, DS2, DE1, DE2. Respectively, the start and end diameters of a tapered solenoid (solenoid spiral starts at the bottom). This model checks if DE<=DS and issues an error message if this condition does not hold.

PS1, PS2. The axial distance (measured along the solenoid axis) between wire centerlines of two adjacent spiral turns (pitch). For cylindrical and tapered solenoids, this model checks if the distance between adjacent turns measured along the cone/cylinder generatrix is greater than Dia.

H1, H2. The elevation of the solenoid start point (see "Topology") above ground.

RotX1, RotX2, RotY1, RotY2, RotZ1, RotZ2. The tilt of solenoid axes is controlled by these angles. RotX1, RotX2 rotate the solenoid axis about local axis X; RotY1, RotY2 rotate the solenoid axis about axis Y; RotZ1, RotZ2 rotate the solenoid about local axis Z (see "Topology" for a definition of local axes). Rotation angles are positive when rotations appear counter-clockwise and the axis about which rotations occur points toward the observer. This model tracks the position of all conducting parts and issues an error if a combination of specified parameters makes a solenoid(s) touch ground or another solenoid. Changes made to the solenoid angular position reflect on its image on the 3D Layout view.

Nts1, Nts2. The number of linear wire segments a model uses to approximate a single spiral turn (see "Implementation Details"). Nseg must be greater than or equal to 6.

Er, Tand. Parameters of material used for optional encasing. The defaults are Er=1, Tand=0.

Parameter Restrictions and Recommendations

  1. NT should be greater or equal to 1.

  2. Model checks that Nts≥6.

  3. Model checks if DE≤DS.

  4. This model checks PS for each inductor. Note that PS is an "axial pitch" (the distance between turn wire centerlines measured along the inductor axis). For conical solenoids this model checks "external pitch" (the distance between turn wire centerlines measured along the cone generatrix). This external pitch must be greater than Dia. When DE=DS, axial and external pitches are equal in value.

Implementation Details

Each spiral turn is broken into Nts linear wire segments and the model evaluates self and mutual RLC parameters of all segments including the image wire segments (due to ground pesence).This model controls the length of each segment and issues an error message if the length of any segment exceeds the wire diameter Dia or warning if segment length is too small (see Recomenadtions for Use). This model accounts for a skin effect and partly for radiation loss.

Recommendations for Use

Note that Port 1 is assigned to the start point of inductor #1 and Port 2 is assigned to the end point of inductor #1 (start point at the bottom and end point at the top). The same is true for ports 3 and 4 attached to inductor #2.

This model predicts the frequency behavior of the following solenoids and in the vicinity of the first self-resonance frequency.

User discretion is advised if this model issues a warning about segment length being too small. CSOLIND assumes that each segment is represented by infinitely thin filament, which means Lseg >>Dia. Thus, very short (relative to wire diameter) segments may cause additional errors. This model issues a warning message if Lseg<6*Dia. This message contains the segment number. All segments with numbers greater than that in violation are also in violation. If DE<DS, segments in violation often belong to a few top turns. You get an approximate estimation of the percentage of segments with reduced accuracy.

Table of conversion AWG (American Wire Gauge) to millimeters (for those who prefer wire gauge for denoting wire diameter).

AWG Wire diameter (mm) AWG Wire diameter (mm) AWG Wire diameter (mm)
12 2.053 25 0.4547 38 0.1007
13 1.828 26 0.4049 39 0.08969
14 1.628 27 0.3606 40 0.07987
15 1.450 28 0.3211 41 0.07112
16 1.291 29 0.2859 42 0.06334
17 1.150 30 0.2546 43 0.05641
18 1.024 31 0.2268 44 0.05023
19 0.9116 32 0.2019 45 0.04473
20 0.8118 33 0.1798 46 0.03983
21 0.7229 34 0.1601 47 0.03547
22 0.6438 35 0.1426 48 0.03160
23 0.5733 36 0.1270 49 0.02813
24 0.5106 37 0.1131 50 0.02505

Layout

The layout for this cell has hard-coded model layers. When you first use this layout cell, a layer named "Solenoid" is added to your drawing layer and model layer list (if they are not already there). Using the model layer mapping, you can assign these layers to draw on any drawing layer. The 2D layout displays a circle the size of the DS parameter plus the Dia size. The 3D layout displays the shapes as a solenoid.

This model has a layout only parameter that controls how the layout cell draws. You access the parameters by selecting the item in the layout, right-clicking and choosing Shape Properties to display the Cell Options dialog box, then clicking the Parameters tab.

Name Value Units Description
NSeg 32 Integer Number of linear segments approximating one spiral turn.

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