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filterStub

Create stub filter in microstrip form

Description

Use the filterStub object to create a stub filter in the microstrip form.

Creation

Description

example

filter = filterStub creates a default stub using a Teflon substrate. The default passband of the filter is centered around 2 GHz.

example

filter = filterStub(Name=Value) sets Properties using one or more name-value arguments. For example, filterStub(PortLineLength=9e-4) creates a stub filter with a port line length of 9e-4 meters. Properties not specified retain their original values.

Properties

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Length of the input and output lines in meters, specified as a positive scalar.

Example: filter = filterStub(PortLineLength=0.0014)

Data Types: double

Width of the input and output lines in meters, specified as a positive scalar.

Example: filter = filterStub(PortLineWidth=8e-4)

Data Types: double

Length of the series line in meters, specified as a positive scalar or a two-element vector.

Example: filter = filterStub(SeriesLineLength=0.0070)

Data Types: double

Width of the series line in meters, specified as a positive scalar or a two-element vector.

Example: filter = filterStub(SeriesLineWidth=8e-4)

Data Types: double

Length of the stubs in meters, specified as a positive scalar or a two-element vector.

Example: filter = filterStub(StubLength=[0.0078 0.0078])

Data Types: double

Width of the stubs in meters, specified as a positive scalar or a two-element vector.

Example: filter = filterStub(StubWidth=[0.0078 0.0078])

Data Types: double

X-offset from the origin in meters, specified as a positive scalar or a two-element vector.

Example: filter = filterStub(StubFeedOffsetX=0.0087)

Data Types: double

Direction of the stubs, specified as a two-element vector of:

  • 1 — Indicates that the stub points to the top.

  • 0 — Indicates that the stub points to the bottom.

Example: filter = filterStub(StubDirection=[0 1])

Data Types: double

Flag to indicate short-circuited stubs, specified as a two-element vector of:

  • 1 — Indicates stub is short-circuited.

  • 0 — Indicates stub is open-circuited.

Example: filter = filterStub(StubShort=[1 1])

Data Types: double

Height of the stub filter from the ground plane in meters, specified as a positive scalar. For multilayer dielectrics, use the Height property to create the filter between the two dielectric layers.

Example: filter = filterStub(Height=0.0028)

Data Types: double

Width of the ground plane in meters, specified as a positive scalar.

Example: filter = filterStub(GroundPlaneWidth=0.0048)

Data Types: double

Type of dielectric material used as a substrate, specified as a dielectric object. The dielectric material in a filterStub object with default properties is Teflon.

Example: d = dielectric("FR4"); filter = filterStub(Substrate=d)

Type of metal used in the conducting layers, specified as a metal object. The type of metal in a filterStub object with default properties is PEC.

Example: m = metal("Copper"); filter = filterStub(Conductor=m)

Object Functions

chargeCalculate and plot charge distribution
currentCalculate and plot current distribution
feedCurrentCalculate current at feed port
getZ0Calculate characteristic impedance of transmission line
layoutPlot all metal layers and board shape
meshChange and view mesh properties of metal or dielectric in PCB component
shapesExtract all metal layer shapes of PCB component
showDisplay PCB component structure or PCB shape
sparametersCalculate S-parameters for RF PCB objects

Examples

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Create a short-circuited stub filter.

filter = filterStub(StubShort=[1 1])
filter = 
  filterStub with properties:

      PortLineLength: 0.0150
       PortLineWidth: 9.0000e-04
    SeriesLineLength: 0.0080
     SeriesLineWidth: 9.0000e-04
          StubLength: [0.0083 0.0083]
           StubWidth: [9.0000e-04 9.0000e-04]
         StubOffsetX: [-0.0090 0.0090]
       StubDirection: [1 0]
           StubShort: [1 1]
              Height: 0.0016
    GroundPlaneWidth: 0.0200
           Substrate: [1x1 dielectric]
           Conductor: [1x1 metal]

Visualize the filter.

show(filter)

Figure contains an axes object. The axes object with title filterStub element contains 8 objects of type patch, surface. These objects represent PEC, feed, Teflon.

Create a multilayered dielectric stub filter.

filter = filterStub;
filter.Substrate = dielectric(Name={'Teflon','Teflon'},EpsilonR=[2.1 2.1], ...
    LossTangent=[0 0],Thickness=[0.8e-3 0.8e-3]);
filter.Height = 0.8e-3;

Visualize the filter.

show(filter);

Figure contains an axes object. The axes object with title filterStub element contains 7 objects of type patch, surface. These objects represent PEC, feed, Teflon.

References

[1] Pozar, David M. Microwave Engineering. 4th ed. Hoboken, NJ: Wiley, 2012.

[2] Wen-Hua Tu and Kai Chang. “Compact Microstrip Bandstop Filter Using Open Stub and Spurline.” IEEE Microwave and Wireless Components Letters 15, no. 4 (April 2005): 268–70. https://doi.org/10.1109/LMWC.2005.845739.

Version History

Introduced in R2022b