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microstripLineCustom

Create coupled form of single or differential microstrip transmission line

Description

Use the microstripLineCustom object to create a coupled form of single or differential microstrip transmission line. A microstrip line is a transmission line that is a basic building block for most RF planar microwave devices. You can use this transmission line to connect two PCB components or to create components such as filters, couplers, and feeding elements of several types of antennas.

A few applications of microstrip transmission lines are:

  • Creating matching feed and coupling networks

  • Transmitting power from one component to another

  • Feeding planar antennas and coupling structures

  • Creating varying inductances or capacitances using open- or short ended- transmission lines

Creation

Description

microstrip = microstripLineCustom creates a coupled form of single or differential microstrip transmission line. The default properties are for a design frequency of 2.5 GHz.

example

microstrip = microstripLineCustom(Name=Value) sets properties using one or more name value pair arguments. For example, microstrip = microstripLineCustom(TraceSpacing=0.0300) creates a custom differential microstrip transmission line with a trace spacing of 0.0300 meters. Properties not specified retain their default values.

Properties

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Types of traces, specified as 'Single' or 'Differential'.

Example: microstrip = microstripLineCustom(TraceType='Differential')

Data Types: string | char

Length of the trace in meters, specified as a positive scalar.

Example: microstrip = microstripLineCustom(TraceLength=0.0371)

Data Types: double

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

Example: microstrip = microstripLineCustom(TraceWidth=0.0041)

Data Types: double

Spacing between the two traces of a differential pair in meters, specified as a positive scalar. Set the TraceType property to 'Differential' to enable this property.

Example: microstrip = microstripLineCustom(TraceSpacing=0.0041)

Data Types: double

Position to offset reference trace along the X-axis, specified as a positive scalar.

Example: microstrip = microstripLineCustom(TraceOffsetX=0.5)

Data Types: double

Height from the custom microstrip line to the ground plane in meters, specified as a positive scalar.

In the case of a multilayer substrate, you can use the height property to create a microstrip line at the interface of the two dielectrics.

Example: microstrip = microstripLineCustom(Height=0.0026)

Data Types: double

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

Example: microstrip = microstripLineCustom(GroundPlaneLength=0.0500)

Data Types: double

Gap between the left coupled traces in meters, specified as a scalar or vector. Set this property to 0, if there are no left coupled traces.

Example: microstrip = microstripLineCustom(LeftCoupledTraceGap=0)

Data Types: double

Gap between the right coupled traces in meters, specified as a scalar or vector. Set this property to 0, if there are no right coupled traces.

Example: microstrip = microstripLineCustom(RightCoupledTraceGap=0)

Data Types: double

Type of dielectric material used as a substrate, specified as a dielectric object. For more information, see dielectric. The thickness of the default dielectric material Teflon is 0.0016 m or the same as the height property.

Example: d = dielectric('FR4'); microstrip = microstripLineCustom(Substrate=d)

Type of metal used in conducting layers, specified as a metal object. For more information see metal.

Example: m = metal('PEC'); microstrip = microstripLineCustom(Conductor=m)

Object Functions

chargeCalculate and plot charge distribution
currentCalculate and plot current distribution
designDesign microstrip transmission line around specified 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 coupled form of differential microstrip line with two pairs of right coupled lines.

microstrip = microstripLineCustom(TraceType='Differential',TraceWidth=...
    0.002,TraceSpacing=0.0005,RightCoupledTraceGap=[0.003,0.003],...
    LeftCoupledTraceGap=0);

View the custom transmission line.

show(microstrip)

Figure contains an axes object. The axes object with title microstripLineCustom element contains 16 objects of type patch, surface. These objects represent PEC, feed, Teflon.

Create a differential microstrip transmission line with no left or right traces

microstrip = microstripLineCustom(TraceType='Differential',TraceSpacing=...
    0.0046,LeftCoupledTraceGap=0,RightCoupledTraceGap=0);

View the transmission line.

show(microstrip)

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

Set the voltage on the transmission line ports. View the layout.

v = voltagePort(4);
v.FeedVoltage = [1 0 1 0];
v.FeedPhase = [0 0 180 0];
figure;
layout(microstrip)

Figure contains an axes object. The axes object with title microstripLineCustom Layout contains 6 objects of type line, text. These objects represent Board Shape, Layer1, Layer3, Feed.

Analyze the current at 2.5 GHz.

figure;
current(microstrip,2.5e9,Excitation=v)

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

References

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

Version History

Introduced in R2022b