txlineCoaxial

Create coaxial transmission line

Since R2020b. Recommended over rfckt.coaxial.

Description

Use the txlineCoaxial object to create a coaxial transmission line. A cross-section of a coaxial transmission line is shown in this figure. The physical characteristics of a coaxial transmission line include the radius of the inner conductor, r_in and the radius of the outer conductor, r_out.

Creation

Syntax

coaxialtxline = txlineCoaxial

coaxialtxline = txlineCoaxial(Name,Value)

Description

coaxialtxline = txlineCoaxial creates a default coaxial transmission line object.

coaxialtxline = txlineCoaxial(Name,Value) sets Properties using one or more name-value pairs. For example, txline = txlineCoaxial('OuterRadius',0.0046) creates a coaxial transmission line with an outer radius of 0.0046 meters.

Properties

Name — Name of coaxial transmission line

'coaxial' (default) | string scalar | character vector

Name of the coaxial transmission line, specified as a string scalar or a character vector.

Example: 'Name','coaxial1'

Example: coaxialtxline.Name = 'coaxial1'

Data Types: char | string

OuterRadius — Outer conductor radius

0.0026 (default) | positive scalar

Outer conductor radius, specified as a positive scalar in meters.

Example: 'OuterRadius',0.0074

Example: coaxialtxline.OuterRadius = 0.0074

Data Types: double

InnerRadius — Inner conductor radius

0.000725 (default) | positive scalar

Inner conductor radius, specified as a positive scalar in meters.

Example: 'InnerRadius',0.000875

Example: coaxialtxline.InnerRadius = 0.000875

Data Types: double

MuR — Relative permeability of dielectric

1 (default) | positive scalar

Relative permeability of the dielectric, specified as a positive scalar.

Relative permeability is the ratio of the permeability of the dielectric, μ, to the permeability in free space, μ₀.

Example: 'MuR',1.5

Example: coaxialtxline.MuR = 1.5

Data Types: double

EpsilonR — Relative permittivity of dielectric

2.3 (default) | positive scalar

Relative permittivity of the dielectric, specified as a positive scalar.

Example: 'EpsilonR',1.4

Example: coaxialtxline.EpsilonR = 1.4

Data Types: double

LossTangent — Loss angle tangent of dielectric

0 (default) | nonnegative scalar

Loss angle tangent of the dielectric, specified as a nonnegative scalar.

Example: 'LossTangent',1

Example: coaxialtxline.LossTangent = 1

Data Types: double

SigmaCond — Conductivity of conductor

Inf (default) | nonnegative scalar

Conductivity of the conductor, specified as a nonnegative scalar in Siemens per meter (S/m).

Example: 'SigmaCond',2

Example: coaxialtxline.SigmaCond = 2

Data Types: double

LineLength — Physical length of transmission line

0.0100 (default) | positive scalar

Physical length of the coaxial transmission line, specified as a positive scalar in meters.

Example: 'LineLength',0.2

Example: coaxialtxline.LineLength = 0.2

Data Types: double

Termination — Stub transmission line termination

'NotApplicable' (default) | 'Open' | 'Short'

Stub transmission line termination, specified as 'NotApplicable', 'Open', or 'Short'.

Example: 'Termination','Short'

Example: coaxialtxline.Termination = 'Short'

Data Types: char

StubMode — Type of stub

'NotAStub' (default) | 'Series' | 'Shunt'

Type of stub, specified as 'NotAStub', 'Series', or 'Shunt'.

Example: 'StubMode','Series'

Example: coaxialtxline.StubMode = 'Series'

Data Types: char

NumPorts — Number of input and output ports

2 (default) | positive scalar

This property is read-only.

Number of input and output ports, specified as a positive scalar.

Data Types: double

Terminals — Terminals of coaxial transmission line

{'p1+' p2+' 'p1-' 'p2-'} (default) | cell array of strings

This property is read-only.

Terminals of coaxial transmission line, specified as cell array of strings.

Data Types: char | string

Object Functions

sparameters	Calculate S-parameters for RF data, network, circuit, and matching network objects
groupdelay	Group delay of S-parameter object or RF filter object or RF Toolbox circuit object
noisefigure	Calculate noise figure of transmission lines, series RLC, and shunt RLC circuits
getZ0	Calculate characteristic impedance with and without dispersion for transmission line
circuit	Circuit object
clone	Create copy of existing circuit element or circuit object

Examples

Calculate Characteristic Impedance with Dispersion for Coaxial Transmission Line

Create a coaxial transmission line.

txline = txlineCoaxial('OuterRadius',1.47e-3,'InnerRadius',0.45e-3,...
            'EpsilonR',3.4,'SigmaCond',5.8e7);

Calculate the characteristic impedance with dispersion for the coaxial transmission line at the frequency of 6 GHz.

z0_f = getZ0(txline,6e9)

z0_f = 
38.4927 - 0.0201i

Version History

Introduced in R2020b

R2023b: Recommended over rfckt.coaxial

txlineCoaxial is recommended over rfckt.coaxial because it enables you to:

• Create a coaxial transmission line.

• Build a circuit object with a coaxial transmission line.

• Model a coaxial transmission line element in an RF chain created using an rfbudget object or the RF Budget Analyzer app, and then export this element to RF Blockset™ or to rfsystem System object™ for circuit envelope analysis.