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coupledMicrostripLine

Create coupled microstrip transmission line

Description

Use the coupledMicrostripLine object to create a coupled microstrip transmission line. Coupled microstrip transmission lines are used to design directional couplers and filters. The combination of even and odd mode impedances determines the coupling ratio between the direct arm and the coupled arm.

Creation

Description

example

coupledmicrostrip = coupledMicrostripLine creates a default coupled microstrip transmission line with a Teflon substrate. The default properties are for a resonating frequency of 1.5 GHz.

example

coupledmicrostrip = coupledMicrostripLine(Name=Value) sets Properties using one or more name-value arguments. For example, coupledMicrostripLine(Length=0.0300) creates a coupled microstrip transmission line of length 0.0300 meters.

Properties

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Length of the coupled microstrip line in meters, specified as a positive scalar.

Example: coupledmicrostrip = coupledMicrostripLine(Length=0.0300)

Data Types: double

Width of the coupled microstrip line in meters, specified as a positive scalar.

Example: coupledmicrostrip = coupledMicrostripLine(Width=0.0041)

Data Types: double

Distance between the direct arm and the coupled arm of the coupled microstrip transmission line, specified as a positive scalar in meters.

Example: coupledmicrostrip = coupledMicrostripLine(Spacing=0.00300)

Data Types: double

Height of the coupled microstrip line from the ground plane, specified as a positive scalar in meters. In the case of a multilayer substrate, use the Height property to create a coupled microstrip line at the interface of the two dielectrics.

Example: coupledmicrostrip = coupledMicrostripLine(Height=0.0023)

Data Types: double

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

Example: coupledmicrostrip = coupledMicrostripLine(GroundPlaneWidth=0.0400)

Data Types: double

Type of the dielectric material used as a substrate, specified as a dielectric object. The thickness of the default dielectric material Teflon is 0.0016 m or the same as the Height property.

Example: d = dielectric("FR4"); coupledmicrostrip = coupledMicrostripLine(Substrate=d)

Data Types: string | char

Type of metal used in the conducting layers, specified as a metal object.

Example: m = metal("PEC"); coupledmicrostrip =coupledMicrostripLine(Conductor=m)

Data Types: string | char

Object Functions

chargeCalculate and plot charge distribution
currentCalculate and plot current distribution
designDesign coupled microstrip transmission line around particular frequency
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 default coupled microstrip line.

cml = coupledMicrostripLine
cml = 
  coupledMicrostripLine with properties:

              Length: 0.0271
               Width: 0.0051
             Spacing: 0.0046
              Height: 0.0016
    GroundPlaneWidth: 0.0300
           Substrate: [1x1 dielectric]
           Conductor: [1x1 metal]

View the coupled microstrip line.

show(cml)

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

Design and view a coupled microstrip line at the interface of a multilayer dielectric.

cml = design(coupledMicrostripLine,4e9,Z0e=75,Z0o=36);
cml.Substrate = dielectric(Name=["Teflon","Teflon"],EpsilonR=[2.1 2.1], ...
    LossTangent=[0 0],Thickness=[0.8e-3 0.8e-3]);
cml.Height = 0.8e-3;
show(cml)

Figure contains an axes object. The axes object with title coupledMicrostripLine element contains 9 objects of type patch, surface. These objects represent PEC, feed, Teflon.

Plot the current and charge distribution on the transmission line.

current(cml,4e9)

Figure contains an axes object. The axes object with title Current distribution contains 4 objects of type patch.

figure
charge(cml,4e9)

Figure contains an axes object. The axes object with title Charge distribution contains 4 objects of type patch.

More About

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References

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

[2] “Microwaves101 | Coupled Line Couplers.” Accessed July 7, 2021. https://www.microwaves101.com/encyclopedias/coupled-line-couplers.

Version History

Introduced in R2021b