microstripLineCustom

Create coupled form of single or differential microstrip transmission line

Since R2022b

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

Syntax

microstrip = microstripLineCustom

microstrip = microstripLineCustom(Name=Value)

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.

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

TraceType — Types of traces

'Single' (default) | 'Differential'

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

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

Data Types: string | char

TraceLength — Length of trace

0.0271 (default) | positive scalar

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

Example: microstrip = microstripLineCustom(TraceLength=0.0371)

Data Types: double

TraceWidth — Width of trace

0.0051 (default) | positive scalar

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

Example: microstrip = microstripLineCustom(TraceWidth=0.0041)

Data Types: double

TraceSpacing — Spacing between two traces of differential pair

0.0046 (default) | positive scalar

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

TraceOffsetX — Position to offset reference trace along X-axis

0 (default) | scalar

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

Example: microstrip = microstripLineCustom(TraceOffsetX=0.5)

Data Types: double

Height — Height from custom microstrip line to ground plane

0.0016 (default) | positive scalar

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

GroundPlaneLength — Length of ground plane

0.0600 (default) | positive scalar

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

Example: microstrip = microstripLineCustom(GroundPlaneLength=0.0500)

Data Types: double

LeftCoupledTraceGap — Gap between left coupled traces

0.0046 (default) | scalar | vector

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

RightCoupledTraceGap — Gap between right coupled traces

0.0046 (default) | scalar | vector

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

Substrate — Type of dielectric material

dielectric object

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

Conductor — Type of metal used in conducting layers

metal("PEC") (default) | metal object

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

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

IsShielded — Flag to add metal shielding

false or 0 (default) | true or 1

Flag to add a metal shielding to the PCB component, specified as a logical 0 or logical 1. The default value is logical 0.

Example: IsShielded = true or 1 add a metal shield.

Note

To enable FEM solver required for the metal shield property, download the Integro-Differential Modeling Framework for MATLAB. To download this add-on:

1. In the Home tab Environment section, click on Add-Ons. This opens the add-on explorer. You need an active internet connection to download the add-on.

2. Search for Integro-Differential Modeling Framework for MATLAB and click Install.

3. To verify if the download is successful, run

   matlab.addons.installedAddons

   in your MATLAB^® session command line.

4. On Windows, to run the IDMF add-on, you must install the Windows Subsystem for Linux (WSL). To install WSL, see Install Linux on Windows with WSL.

   The Windows Defender Firewall can block the PostgreSQL server when using the IDMF add-on. To resolve this issue, you can allow the server to communicate on desired networks if the firewall prompts. Alternatively, you can manually add the executable file of the PostgreSQL server located in <matlabroot>\sys\postgresql\win64\PostgreSQL\bin\postgres.exe. For more information, see https://support.microsoft.com/en-us/windows/risks-of-allowing-apps-through-windows-defender-firewall-654559af-3f54-3dcf-349f-71ccd90bcc5c.

Data Types: logical

Shielding — Metal shielding

shape.Box object

This property is read-only.

Metal shield for the PCB component, specified as a shape.Box object. The length and width of the box must be equal to the length and width of the ground plane. The center of the box is at [0 0 Shielding.Height].

Dependencies

To enable the Shielding property, set the IsShielded property to true or 1.

Connector — Type of RF connector

RFConnector object

Type of RF connector assembled at the feed locations of the PCB component, specified as a RFConnector object.

Example: Create connector from RFConnector object like this: coaxial = RFConnector adds a coaxial connector.

Dependencies

To enable the Connector property, set the IsShielded property to true or 1.

Object Functions

charge	Calculate and plot charge distribution
current	Calculate and plot current distribution
design	Design microstrip transmission line around specified frequency
feedCurrent	Calculate current at feed port
getZEven	Calculate even mode impedance of differential PCB transmission line
getZOdd	Calculate odd mode impedance of differential PCB transmission line
layout	Plot all metal layers and board shape
mesh	Change and view mesh properties of metal or dielectric in PCB component
propagationDelay	Compute propagation delay of transmission line
rlgc	Compute resistances, inductances, conductances, and capacitances
shapes	Extract all metal layer shapes of PCB component
show	Display PCB component structure or PCB shape
sparameters	Calculate S-parameters for RF PCB objects
RFConnector	Create RF connector

Examples

Differential Right Coupled Microstrip Line

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)

Differential Microstrip Line with No Left or Right Traces

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)

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)

Analyze the current at 2.5 GHz.

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

References

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

Version History

Introduced in R2022b

R2023b: Metal shielding for custom microstrip transmission line

Use the IsShielded, Shielding, and Connector properties to add a metal shield to the microstripLineCustom object.