Engee documentation

txlineMicrostrip

Creates a microstrip transmission line.

Library

EngeeRF

Description

Use the function txlineMicrostrip to create a standard, embedded, inverted, or suspended microstrip transmission line.

The following figure shows the cross sections of the four types of microstrip transmission line. Its physical characteristics include the width of the conductor , the thickness of the conductor , the thickness of the dielectric , relative permittivity and the height of the conductor above the grounding plane .

txlinemicrostrip 1 entxlinemicrostrip 2 en

txlinemicrostrip 3 entxlinemicrostrip 4 en

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

Syntax

Function call

  • txline = txlineMicrostrip() — creates a standard microstrip transmission line object with default properties.

  • txline = txlineMicrostrip(Name=Value) — sets properties specified by one or more arguments of the type «name-value». Unspecified properties retain their default values.

Arguments

Input arguments «name-value»

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

Example: txline = txlineMicrostrip(Width = 0.0046) creates a standard microstrip transmission line with a width of 0.0046 M. You can specify several pairs «name-value».

# Type — type of microstrip transmission line

+ "Standard" (by default) | "Embedded" | "Inverted" | "Suspended"

Details

The type of microstrip transmission line specified by one of the following values:

  • "Standard" — standard microstrip transmission line;

  • "Embedded" — built-in microstrip transmission line;

  • "Inverted" — inverted microstrip transmission line;

  • "Suspended" — suspended microstrip transmission line.

Типы данных

String

# lineLength — the physical length of the transmission line

+ 0.01 (by default) | scalar

Details

The physical length of the microstrip transmission line, specified as a positive scalar in meters.

Типы данных

Float64

# Width — the physical width of the transmission line

+ 0.0006 (by default) | scalar

Details

The physical width of the microstrip transmission line, set as a positive scalar in meters.

Типы данных

Float64

# Height — the physical height of the conductor

+ 0.000635 (by default) | scalar

Details

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

Dependencies

To use this argument, set for the argument Type meaning "Embedded", "Inverted" or "Suspended".

Типы данных

Float64

# totalHeight — full height

+ 0.000635 (by default) | scalar

Details

The total height, set as a positive scalar in meters.

Типы данных

Float64

# DielectricThickness is the dielectric thickness of the microstrip transmission line

+ 0.000635 (by default) | scalar

Details

The dielectric thickness of an inverted, embedded, or suspended microstrip transmission line, specified as a positive scalar in meters. The default dielectric thickness values for embedded, inverted, and suspended microstrip transmission lines are shown in the table, where — thickness of the dielectric, — the width of the conductor.

Type of microstrip transmission line The value of the argument DielectricThickness by default Expected values

"Embedded"

Height * 2

"Inverted"

Height

"Suspended"

Height / 2
The default function is txlineMicrostrip sets the dielectric thickness of a standard microstrip transmission line equal to the value of the argument Height.

Dependencies

To use this argument, set for the argument Type meaning "Embedded", "Inverted" or "Suspended".

Типы данных

Float64

# Thickness — the physical thickness of the transmission line

+ 5.0e−6 (by default) | scalar

Details

The physical thickness of the microstrip transmission line, given as a positive scalar in meters. It is now possible to simulate a microstrip transmission line with a thickness of 0 mm.

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

+ 0.0 (by default) | scalar

Details

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

Типы данных

Float64

# SigmaCond — linear conductivity

+ Inf (by default) | scalar

Details

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

Типы данных

Float64

# Termination — shorting 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".

# Name — name of the transmission line

+ "Microstrip" (default) | line

Details

The name of the microstrip transmission line, set as a string.

Типы данных

String

# Terminals — terminals of the microstrip transmission line

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

Details

Terminals of a microstrip transmission line, specified as a tuple of strings from 4 elements.

This argument is read-only.

# 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

Output arguments

# txline — transmission line object

+ object

Details

A microstrip transmission line object containing the following properties:

  • Type — type of transmission line;

  • LineLength — length of the transmission line;

  • Width — width of the transmission line;

  • Height — height of the conductor;

  • TotalHeight — full height;

  • DielectricThickness — the thickness of the transmission line dielectric;

  • Thickness — the thickness of the transmission line;

  • EpsilonR — relative dielectric constant;

  • LossTangent — tangent of the dielectric loss angle;

  • SigmaCond — linear conductivity;

  • Termination — shorting of the transmission loop line;

  • StubMode — type of train;

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

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

  • NumPorts — number of ports;

  • 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, displayed only after adding the child schema to the parent schema.;

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

Examples

S-parameters and group delay of the microstrip transmission line

Details

Let’s create a microstrip transmission line with the following properties:

  • Width: 0.08 mm;

  • Line length: 12.2777 mm;

  • Thickness: 10e−6 m;

  • Relative permittivity: 3.9;

  • Linear conductivity: 5.88e7 Cm/m.

using EngeeRF

microstriptxline = txlineMicrostrip(LineLength = 12.2777e-3,
                                    Width = 0.08e-3, Thickness = 10e-6,
                                    EpsilonR = 3.9, SigmaCond = 5.88e7)

Calculate the S-parameters of the transmission line at the frequency 10 GHz.

sparam = sparameters(microstriptxline, 10e9, 50)

println("Impedance: ", sparam.Impedance,
        "\nNumPorts: ", sparam.NumPorts,
        "\nFrequencies: ", sparam.Frequencies,
        "\nParameters: ", sparam.Parameters)
Impedance: 50
NumPorts: 2
Frequencies: [1.0e10]
Parameters: ComplexF64[0.6948678545439806 + 0.24909256643028208im -0.22768417547072084 + 0.6233009650582779im; -0.22768417547072078 + 0.6233009650582778im 0.6948678545439806 + 0.2490925664302822im;;;]

Calculate the group delay of the transmission line at the frequency 10 GHz.

freqs = [10e9, 10e9 + 1e3]
gd = groupdelay(microstriptxline, freqs)
2-element Vector{Float64}:
 4.9333968511297063e-11
 4.9333968511297063e-11

S-parameters of the suspended microstrip line

Details

Let’s create a microstrip transmission line with a copper conductor and a Teflon substrate.

using EngeeRF

tx = txlineMicrostrip(Type = "Suspended", LineLength = 0.04705,
                      Width = 3.5e-3, Height = 1.6e-3,
                      DielectricThickness = 0.8e-3, Thickness = 3.556e-5,
                      EpsilonR = 2.1, LossTangent = 0.2e-3, SigmaCond = 596e5)

Let’s calculate and plot the S-parameters with the reference impedance 50 Om.

freq = (1:40) * 100e6
Srf = sparameters(tx, freq, 50)

rfplot(Srf)

txlinemicrostrip 1

Algorithms

If for an argument StubMode the value is set "Shunt", then the two-port network consists of a loopback transmission line that can be closed or opened, as shown in the following figure.

rfckt coaxial 1

Here — the input impedance of the parallel circuit. The ABCD parameters for the parallel loop are calculated as follows:







If for an argument StubMode the value is set "Series", then the two-port network is a serial transmission line that can be closed or opened, as shown in the following figure.

rfckt coaxial 2

Here — input impedance of the serial circuit. The ABCD parameters for the serial loop are calculated as follows:







Literature

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

  2. Wadell, Brian C. Transmission Line Design Handbook. The Artech House Microwave Library. Boston: Artech House, 1991.