MSInd (Microstrip Spiral Inductor)

Symbol

Parameters

Name	Description	Unit	Default
Subst	Microstrip substrate name	None	MSub1
F	Center frequency	GHz	1
L	Inductance	nH	10
Ri	Inner radius measured to center of conductor	mil	50
W	Conductor width	mil	10
S	Conductor spacing	mil	10
W1	Width of strip connected to pin 1	mil	10
W2	Width of strip connected to pin 2	mil	10
Delta	Incremental number of turns for tuning inductance (need not be integer)	None	0

Notes

1. MSInd designs a microstrip spiral inductor. The underlying design uses the MSIND component contained in the Tlines-Microstrip palette.
2. The design is accomplished using a simple model that specifies the number of turns in the spiral inductor required to achieve the inductance L at the design center frequency given the remaining physical parameters.
3. The value of Ri specifies the distance from the center of the inductor to the center of the conductor at its innermost point in the spiral. Refer to the discussion of the MSIND component in the Microstrip Components documentation for a more detailed discussion of this parameter.
4. The tuning parameter Delta represents the number of additional turns to add to the outside of the structure. Fractional numbers of turns are accommodated (i.e. Delta need not be an integer value). The design process may not produce the parameters that perfectly achieve the specified inductance. Manual tuning of the inductance can be performed by specifying the parameter Delta, which represents the number of turns to add to the design. For example, if the design process determines that the number of required turns is 1.2 and Delta is set to 0.3, the actual number of turns in the underlying inductor design will be 1.2+0.3=1.5. Delta can be positive or negative and, as shown in this example, need not be an integer.
5. The Optimization Assistant tunes the number of turns to achieve the desired inductance.
6. A SmartComponent subnetwork is empty until the Design Assistant is used to generate the design. Refer to Design Assistant.

Example

A MSInd component was used to design a 1 nH inductor at a center frequency of 3 GHz. Optimization yielded a value of Delta = -0.53.