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design

Design stepped impedance low pass filter around desired cut-off frequency

Since R2021b

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Syntax

sifilter = design(sifilterobj,frequency)
sifilter = design(___,Name=Value)

Description

sifilter = design(sifilterobj,frequency) designs a stepped impedance low pass filter around the cut-off frequency.

example

sifilter = design(___,Name=Value) designs a stepped impedance low pass filter with additional options specified by name-value arguments.

Note

  • PCB components designed using the design function operate around the specified frequency with a 10-15% tolerance.

  • The design for stepped impedance low pass filter is based on analytical equations. Analyzing the parameters using EM-simulation model causes a shift in the cut-off frequency towards the lower end of the frequency range. This is an expected behavior due to the coupling effect.

Examples

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Open Live Script

Design a sixth order stepped impedance low pass filter at 2.5 GHz with 20 ohm low impedance line, 120 ohm high impedance line on FR4 substrate of thickness 1.58 mm.

sifilter = filterStepImpedanceLowPass(FilterOrder=6,Height=1.58e-3) ;
Sub  = dielectric(Name='Fr4',EpsilonR=4.2,LossTangent=0.02,Thickness=1.58e-3);
sifilter.Substrate = Sub;
sifilterobj = design(sifilter,2.5e9,Z0=50,LowZ=20,HighZ=120);

View the filter.

show(sifilterobj);

Input Arguments

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Stepped impedance low pass filter, specified as a filterStepImpedanceLowPass object.

Example: sifilterobj = filterStepImpedanceLowPass; design(sifilterobj,2e9) designs a coupled line filter around a frequency of 2 GHz.

Design frequency of the stepped impedance low pass filter, specified as a real positive scalar in hertz.

Example: 5e9

Data Types: double

Name-Value Arguments

Example: Z0=75

Reference impedance, specified as a positive scalar in ohms.

Data Types: double

Low impedance line, specified as a positive scalar in ohms.

Data Types: double

High impedance line, specified as a positive scalar in ohms.

Data Types: double

Type of filter, specified as 'Butterworth', or 'Chebyshev'.

Data Types: char | string

Passband factor of the Chebyshev filter, specified as positive scalar in decibels. For Butterworth filter, the passband factor is not required.

Data Types: double

Output Arguments

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Stepped impedance low pass filter around specified frequency, returned as a filterStepImpedanceLowPass object.

Version History

Introduced in R2021b

See Also