stubRadialShunt

Create single- and double-radial stub shunt on X-Y plane

Since R2021b

Description

Use the stubRadialShunt object to create a single- or double-radial stub shunt on the X-Y plane.

Radial stubs provide broadly resonant RF short circuits by introducing the short at a concentrated point. When cascaded with high-impedance quarter-wavelength transmission lines, radial stubs provide an effectively decoupled network for microwave amplifiers and other active components.

Creation

Syntax

stub = stubRadialShunt

stub = stubRadialShunt(Name=Value)

Description

stub = stubRadialShunt creates a single-radial stub shunt in the X-Y plane. The stub dimensions are for the frequency range of 3-5 GHz with a resonant frequency of 4.2 GHz on the X-Y plane.

stub = stubRadialShunt(Name=Value) sets Properties using one or more name-value arguments. For example, stubRadialStub(OuterRadius=0.0070) creates a radial stub shunt with an outer radius of 0.0070 meters. Properties not specified retain their default values.

Properties

StubType — Type of radial stub

"Single" (default) | "Double"

Type of radial stub, specified as "Single" or "Double".

Example: stub = stubRadialShunt(StubType="Double")

Data Types: string | char

OuterRadius — Outer radius of radial stub

0.0085 (default) | positive scalar | two-element vector

Outer radius of the radial stub in meters, specified as a positive scalar or a two-element vector of positive elements. Specify a two-element vector for a double-radial stub.

Example: stub = stubRadialShunt(OuterRadius=0.0070)

Data Types: double

InnerRadius — Inner radius of radial stub

0.0012 (default) | positive scalar | two-element vector

Inner radius of the radial stub in meters, specified as a positive scalar or a two-element vector of positive elements. Specify a two-element vector for a double-radial stub.

Example: stub = stubRadialShunt(InnerRadius=0.0023)

Data Types: double

Angle — Angle of stub

90 (default) | positive scalar in the range [5, 175] | two-element vector in the range [5, 175]

Angle of the stub in degrees, specified as a positive scalar or a two-element vector of positive elements. Specify a two-element vector for a double-radial stub. The stub angles must be greater than or equal to 5 degrees and less than or equal to 175 degrees.

Example: stub = stubRadialShunt(Angle=60)

Data Types: double

PortLineWidth — Width of microstrip line

0.0025 (default) | positive scalar

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

Example: stub = stubRadialShunt(PortLineWidth=0.0035)

Data Types: double

PortLineLength — Length of microstrip line

0.0137 (default) | positive scalar

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

Example: stub = stubRadialShunt(PortLineLength=0.0237)

Data Types: double

Height — Height of radial stub from ground plane

0.0016 (default) | positive scalar

Height of the radial stub from the ground plane, specified as a positive scalar.

Example: stub = stubRadialShunt(Height=0.0015)

Data Types: double

GroundPlaneLength — Length of ground plane

0.0200 (default) | positive scalar

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

Example: stub = stubRadialShunt(GroundPlaneLength=0.046)

Example: double

GroundPlaneWidth — Width of ground plane

0.0200 (default) | positive scalar

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

Example: stub = stubRadialShunt(GroundPlaneWidth=0.046)

Example: 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 stubRadialShunt object with default properties is Teflon. The thickness of the default dielectric material Teflon is 0.8 mm or the same as the Height property.

Example: d = dielectric("FR4"); stub = stubRadialShunt(Substrate=d)

Data Types: string | char

Conductor — Type of metal used in conducting layers

metal object

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

Example: m = metal("PEC"); stub = stubRadialShunt(Conductor=m)

Data Types: string | char

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 regarding firewalls, see Allowing apps through Windows Defender Firewall .

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]. You can modify the property after creating the object.

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
feedCurrent	Calculate current at feed port
getZ0	Calculate characteristic impedance of transmission line
layout	Plot all metal layers and board shape
mesh	Change and view mesh properties of metal or dielectric in PCB component
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

Create Default Radial Stub Shunt

Create a default radial stub shunt.

stub = stubRadialShunt

stub = 
  stubRadialShunt with properties:

             StubType: 'Single'
          OuterRadius: 0.0085
          InnerRadius: 0.0012
                Angle: 90
       PortLineLength: 0.0137
        PortLineWidth: 0.0025
               Height: 8.0000e-04
    GroundPlaneLength: 0.0200
     GroundPlaneWidth: 0.0200
            Substrate: [1x1 dielectric]
            Conductor: [1x1 metal]
           IsShielded: 0

View the radial stub shunt.

show(stub)

Create Double Shunt Radial Stub

Create shunt radial stub of type double.

stub = stubRadialShunt(StubType='double');
stub.OuterRadius = [0.0085 0.0065];
stub.InnerRadius = [0.0012 0.0008];
stub.Angle       = [90 60];

View shunt radial stub.

show(stub)

Plot s-parameters.

spar = sparameters(stub,linspace(3e9,5e9,50));
rfplot(spar)

More About

Parametric Analysis Guidelines

• Increase the Angle to shift the resonance of the stub to a lower frequency.

• Increase the OuterRadius to shift the resonance of the stub to a lower frequency.

• Adjust the OuterRadius and increase the Angle to design a radial stub at a desired frequency, line length, low insertion loss, and wide bandwidth.

References

[1] Wang , Zhebin, and Chan-Wang Park. “Novel Wideband GaN HEMT Power Amplifier Using Microstrip Radial Stub to Suppress Harmonics.” In 2012 IEEE/MTT-S International Microwave Symposium Digest, 1–3. Montreal, QC, Canada: IEEE, 2012. https://doi.org/10.1109/MWSYM.2012.6259464.

[2] Singh, Prashant, and Tiwary Anjini. “Novel Compact Dual Bandstop Filter Using Radial Stub.” Microwave Review 21 (September 1, 2015): 17–22.

Version History

Introduced in R2021b

R2023b: Metal shielding for coplanar waveguide

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