Engee documentation

rfckt.twowire

Creates a two-wire transmission line.

Library

EngeeRF

Description

Use the function rfckt.twowire to create a two-wire transmission line characterized by the size of the line, the type of loop and the short circuit.

The following figure shows a cross-section of a two-wire transmission line. Its physical characteristics include the radius of the dielectric wires , the distance between the centers of the wires , as well as the relative permittivity and relative magnetic permeability wires. It is assumed that the relative permittivity and relative magnetic permeability are homogeneous.

rfckt twowire en

It is recommended to use the function txlineTwoWire Instead of rfckt.twowire because it allows:

  • Create a two-wire transmission line.

  • Create an object circuit with a two-wire transmission line.

  • Simulate an element of a two-wire transmission line in an RF circuit created using an object rfbudget, and then export this element to the EngeeRF library for circuit envelope analysis.

Syntax

Function call

  • h = rfckt.twowire() — creates an object of a parallel RLC circuit, all properties of which have default values. The default object is equivalent to an end-to-end two-port network, i.e. the resistor, inductor and capacitor are replaced by a short circuit.

  • h = rfckt.twowire(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: rfckt.twowire(Radius = 7.5e-4) creates a two-wire transmission line object with the radius of the conducting wire 7.5e−4 meters. You can specify multiple pairs «name-value».

# AnalyzedResult — calculated values of S-parameters, noise factor, OIP3 and group delay

+ the rfdata.data object

Details

Calculated values of S-parameters, noise factor, OIP3, and group delay, set as an object rfdata.data. For more information, see Algorithms.

This argument is read-only.
Типы данных

function_handle

# Separation — the distance between the wire centers, m

+ 0.00162 (default) | scalar

Details

The distance between the wire centers, set as a positive scalar in meters.

Типы данных

Float64

# EpsilonR — relative permittivity

+ 2.3 (by default) | scalar

Details

The relative permittivity of a dielectric, given as a scalar. The relative permittivity is the ratio of the dielectric constant of a dielectric to dielectric constant in vacuum .

Типы данных

Float64

# lineLength — the physical length of the transmission line, m

+ 0.01 (default) | scalar

Details

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

Типы данных

Float64

# LossTangent is the tangent of the dielectric loss angle

+ 0 (by default) | scalar

Details

The tangent of the dielectric loss angle, defined as a scalar.

Типы данных

Float64

# MuR — relative magnetic permeability of a dielectric

+ 1 (by default) | scalar

Details

The relative magnetic permeability of a dielectric, given as a scalar. The relative magnetic permeability is the ratio of the magnetic permeability of a dielectric magnetic permeability in vacuum .

Типы данных

Float64

# Name — the name of the object

+ "Two-Wire Transmission Line" (by default) | line

Details

The name of the object, set as a string.

This argument is read-only.
Типы данных

String

# NPort — number of ports

+ 2 (by default) | a positive integer

Details

The number of ports specified as a positive integer.

This argument is read-only.
Типы данных

Int64

# Radius is the radius of the wire, m

+ 0.00067 (by default) | scalar

Details

The radius of a conductive wire in a two-wire transmission line, set as a positive scalar in meters.

Типы данных

Float64

# SigmaCond — linear conductivity, Cm/m

+ Inf (by default) | scalar

Details

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

Типы данных

Float64

# StubMode — loop type

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

Details

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

# 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".

Output arguments

# h — the object of a two-wire transmission line

+ object

Details

The object of a two-wire transmission line.

Examples

Creating a two-wire transmission line

Details

Let’s create a two-wire transmission line with a radius of a conductive wire 7.5e−4 meters.

using EngeeRF

h = rfckt.twowire(Radius = 7.5e-4)

println("Radius: ", h.Radius,
        "\nSeparation: ", h.Separation,
        "\nMuR: ", h.MuR,
        "\nEpsilonR: ", h.EpsilonR,
        "\nLossTangent: ", h.LossTangent,
        "\nSigmaCond: ", h.SigmaCond,
        "\nLineLength: ", h.LineLength,
        "\nStubMode: ", h.StubMode,
        "\nTermination: ", h.Termination,
        "\nnPort: ", h.nPort,
        "\nAnalyzedResult: ", h.AnalyzedResult,
        "\nName: ", h.Name)
Radius: 0.00075
Separation: 0.00162
MuR: 1.0
EpsilonR: 2.3
LossTangent: 0.0
SigmaCond: Inf
LineLength: 0.01
StubMode: NotAStub
Termination: NotApplicable
nPort: 2
AnalyzedResult: nothing
Name: Two-Wire Transmission Line

Algorithms

  • If we model the transmission line as a line without a loop, the method analyze First, it calculates the ABCD parameters at each frequency contained in the vector of simulated frequencies. Then he uses the function abcd2s to convert ABCD parameters to S parameters.

    Method analyze calculates the ABCD parameters using the physical length of the transmission line and a comprehensive distribution constant , using the following equations:







    where and — vectors, the elements of which correspond to the elements of the frequency vector specified in the input argument Freq functions analyze. Both vectors can be expressed in terms of resistance , inductance , conductivity and capacity per unit length (meters) as follows:



    where







    In the above equations:

    • — radius of dielectric wires;

    • — the distance between the centers of the wires;

    • — linear conductivity;

    • — magnetic permeability of the dielectric;

    • — dielectric constant of the dielectric;

    • — the imaginary part , where

      • — dielectric constant in vacuum;

      • — the value of the argument EpsilonR;

      • — the value of the argument LossTangent;

    • — the depth of current penetration into the conductor;

    • — the vector of simulated frequencies determined by the block Outport (CE);

    • .

  • If we model the transmission line as a parallel or serial loop, the method analyze first, it calculates the ABCD parameters at the specified frequencies. Then he uses the function abcd2s to convert ABCD parameters to S parameters.

    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 — 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. Pozar, David M. Microwave Engineering, John Wiley & Sons, Inc., 2005.