Engee documentation

txlineCPW

Creates a coplanar waveguide.

Library

EngeeRF

Description

Use the function txlineCPW to create a CoPlanar waveguide (CPW). An object txlineCPW It can also be used to create a transmission line based on a coplanar waveguide with an infinite bottom conductor or a grounding plane.

The following figure shows the cross section of a coplanar waveguide. Its physical characteristics include the width of the conductor , the thickness of the conductor , the width of the gap , the height of the substrate and the dielectric constant .

txlinecpw en

The figure also shows — the value of the argument SigmaCond, — the value of the argument EpsilonR and — the value of the argument LossTangent.

Syntax

Function call

  • txline = txlineCPW() — creates a coplanar waveguide object whose properties are set by default.

  • txline = txlineCPW(Name=Value) — sets properties specified by one or more name-value arguments. Unspecified properties retain their default values.

Arguments

Name-value input arguments

Specify optional argument pairs as Name=Value, where Name — the name of the argument, and Value — the appropriate value.

Example: txline = txlineCPW(SlotWidth = 0.0046) creates a CPW transmission line object with a slot width 0.0046 meters. You can specify multiple name-value pairs.

# Name — name of the transmission line

+ "CPW" (by default) | line

Details

The name of the coplanar waveguide, set as a string.

Типы данных

String

# ConductorWidth — physical width, m

+ 0.0006 (by default) | scalar

Details

The physical width of the conductor, set as a positive scalar in meters.

Типы данных

Float64

# SlotWidth — the physical width of the slot, m

+ 0.0002 (by default) | scalar

Details

The physical width of the gap, set as a positive scalar in meters.

Типы данных

Float64

# Height is the physical height of the conductor or the thickness of the dielectric, m

+ 0.000635 (by default) | scalar

Details

The physical height of the conductor or the thickness of the dielectric, given as a positive scalar in meters.

Типы данных

Float64

# Thickness — physical thickness, m

+ 5e−6 (default) | scalar

Details

The physical thickness of a coplanar waveguide, given as a positive scalar in meters.

Типы данных

Float64

# EpsilonR — relative permittivity

+ 9.8 (by default) | scalar

Details

The relative permittivity of a dielectric, given as a positive scalar.

Типы данных

Float64

# LossTangent is the tangent of the dielectric loss angle

+ 0 (by default) | scalar

Details

The tangent of the dielectric loss angle, given as a non-negative scalar.

Типы данных

Float64

# SigmaCond — linear conductivity, Cm/m

+ Inf (by default) | scalar

Details

Linear conductivity, given as a non-negative scalar in Siemens per meter (Cm/m).

Типы данных

Float64

# lineLength — physical length, m

+ 0.01 (by default) | scalar

Details

The physical length of a coplanar waveguide, given as a positive scalar in meters.

Типы данных

Float64

# ConductorBacked — infinite bottom conductor or ground plane

+ false (default) | true

Details

The option of taking into account the infinite lower conductor or the grounding plane, set as a logical value. When specifying the value false The function creates a transmission line without a conductive substrate.

Типы данных

Bool

# Termination — closing of the transmission loop
"NotApplicable" (by default) | "Open" | "Short"

Details

The short circuit of the transmission loop, set by one of the following values: "NotApplicable", "Open", "Short".

# StubMode — loop type

+ "NotAStub" (by default) | "Series" | "Shunt"

Details

The type of loop specified by one of the following values: "NotAStub", "Series", "Shunt".

# NumPorts — number of input and output ports

+ 2 (by default) | scalar

Details

The number of input and output ports, set as a positive scalar.

This argument is read-only.
Типы данных

Int64

# Terminals — terminals of the coplanar waveguide

+ ("p1+", "p2+", "p1−", "p2−") (by default) | tuple of strings

Details

Terminals of a coplanar waveguide, specified as a tuple of strings from 4 elements.

This argument is read-only.

Output arguments

# txline — transmission line object

+ object

Details

A coplanar waveguide object containing the following properties:

  • Name — the name of the object as a string, for example "CPW";

  • ConductorWidth — width of the conductor;

  • SlotWidth — width of the gap;

  • Height — the height of the conductor or the thickness of the dielectric;

  • Thickness — the thickness of the transmission line;

  • EpsilonR — relative dielectric constant;

  • LossTangent — tangent of the dielectric loss angle;

  • SigmaCond — linear conductivity;

  • ConductorBacked — infinite bottom conductor or ground plane;

  • LineLength — length of the transmission line;

  • StubMode — type of train;

  • Termination — shorting of the transmission loop line;

  • Terminals — terminal names in the form of a tuple of strings;

  • NumPorts — number of ports;

  • Ports — port names as a tuple of strings: ("p1", "p2");

  • Parent — the parent schema that the chain object belongs to;

  • ParentNodes — nodes of the parent schema in the form of an array of integers, displayed only after adding the child schema to the parent schema;

  • ParentPath — the full path to the parent schema as a string. This path is displayed only after adding the child schema to the parent schema.

Examples

S-parameters of the coplanar waveguide

Details

Let’s create a coplanar waveguide with the following properties:

  • The width of the conductor: 45 microns;

  • Width of the slot: 50 microns;

  • The height of the substrate: 525 microns;

  • Thickness: 1 microns;

  • Dielectric constant GaAs or : 2.5 F/m;

  • Conductivity: 3.33e7 Cm/m.

using EngeeRF

cpwtxline = txlineCPW(ConductorWidth = 45e-6, SlotWidth = 50e-6, Height = 525e-6,
                      Thickness = 1e-6, EpsilonR = 2.5, SigmaCond = 3.33e7)

println("Name: ", cpwtxline.Name,
        "\nConductorWidth: ", cpwtxline.ConductorWidth,
        "\nSlotWidth: ", cpwtxline.SlotWidth,
        "\nHeight: ", cpwtxline.Height,
        "\nThickness: ", cpwtxline.Thickness,
        "\nEpsilonR: ", cpwtxline.EpsilonR,
        "\nLossTangent: ", cpwtxline.LossTangent,
        "\nSigmaCond: ", cpwtxline.SigmaCond,
        "\nConductorBacked: ", cpwtxline.ConductorBacked,
        "\nLineLength: ", cpwtxline.LineLength,
        "\nStubMode: ", cpwtxline.StubMode,
        "\nTermination: ", cpwtxline.Termination,
        "\nTerminals: ", cpwtxline.Terminals,
        "\nNumPorts: ", cpwtxline.NumPorts)
Name: CPW
ConductorWidth: 4.5e-5
SlotWidth: 5.0e-5
Height: 0.000525
Thickness: 1.0e-6
EpsilonR: 2.5
LossTangent: 0.0
SigmaCond: 3.33e7
ConductorBacked: false
LineLength: 0.01
StubMode: NotAStub
Termination: NotApplicable
Terminals: ("p1+", "p2+", "p1+", "p2-")
NumPorts: 2

Calculate the S-parameters of the transmission line at the frequency 20 GHz.

sparam = sparameters(cpwtxline, 20e9)

println("Impedance: ", sparam.Impedance,
        "\nNumPorts: ", sparam.NumPorts,
        "\nFrequencies: ", sparam.Frequencies,
        "\nParameters: ", sparam.Parameters)
Impedance: 50.0
NumPorts: 2
Frequencies: [2.0e10]
Parameters: ComplexF64[0.4346981457028414 - 0.3008286591017166im 0.48475804881429296 + 0.6289353847109423im; 0.4847580488142931 + 0.6289353847109427im 0.4346981457028413 - 0.30082865910171663im;;;]

Literature

  1. Garg, Ramesh, I. J. Bahl, and Maurizio Bozzi. Microstrip Lines and Slotlines. 3rd ed. Artech House Microwave Library. Boston: Artech House, 2013.