rfckt.rlcgline

Passive component or network

Description

Use the rfckt.rlcgline object to create a RLCG transmission line that is characterized by line loss, line length, stub type, and termination.

Note

txlineRLCGLine is recommended over rfckt.rlcgline because it enables you to:

Create a RLCG transmission line that is characterized by line loss, line length, stub type, and termination.
Build a circuit object with a RLCG transmission line.
Model a RLCG 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.

(since R2023b)

Creation

Syntax

h = rfckt.rlcgline

h = rfckt.rlcgline(Name,Value)

Description

h = rfckt.rlcgline returns an RLCG transmission line object whose properties are set to their default values.

example

h = rfckt.rlcgline(Name,Value) sets properties using one or more name-value pairs. For example, rfckt.rlcgline('LineLength',0.04) creates a RLGC transmission line with a physical length of 0.04 meters. You can specify multiple name-value pairs. Enclose each property name in a quote. Properties not specified retain their default values.

Properties

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`AnalyzedResult` — Computed S-parameters, noise figure, OIP3, and group delay values
`rfdata.data` object

Computed S-parameters, noise figure, OIP3, and group delay values, specified as rfdata.data object. AnalyzedResult is a read-only property. For more information refer, .Algorithms.

Data Types: function_handle

`R` — Resistance values per length
vector

Resistance values per length, specified as a vector in ohms per meter. The resistance values correspond to the frequency values in 'Freq' property. All values must be positive. The default value is 0.

Data Types: double

`C` — Capacitance values per length
vector

Capacitance values per length, specified as a vector in farads per meter. The capacitance values correspond to the frequency values in 'Freq' property. All values must be positive. The default value is 0.

Data Types: double

`Freq` — Frequency data
M-element vector

Frequency data for the RLCG values, specified as a M-element vector. The values must be positive and correspond to the order of the RLCG values. The default value is 1e9.

Data Types: double

`G` — Conductance values per length
vector

Conductance values per length, specified as a vector in Siemens per meter. The conductance values correspond to the frequency values in 'Freq' property. All values must be positive. The default value is 0.

Data Types: double

`IntpType` — Interpolation method used in `rfckt.rlcgline`
`'Linear'` (default) | `'Spline'` | `'Cubic'`

Interpolation method used in rfckt.rlcgline, specified as one of the following values:

Method	Description
`Linear`	Linear interpolation
`Spline`	Cubic spline interpolation
`Cubic`	Piecewise cubic Hermite interpolation

Data Types: char

`L` — Inductance values per length
vector

Inductance values per length, specified as vector in henries per meter. The inductance values correspond to the frequency values in 'Freq' property. All values must be positive. The default value is 0.

Data Types: double

`LineLength` — Physical length of transmission line
scalar

Physical length of transmission line, specified as a scalar in meters. The default value is 0.01.

Data Types: double

`Name` — Object name
`'RLCG Transmission Line'` (default) | `1-by-N` character array

Object name, specified as a 1-by-N character array. Name is a read-only property.

Data Types: char

`nport` — Number of ports
positive integer

Number of ports, specified as a positive integer. nportt is a read-only property. The default value is 2.

Data Types: double

`StubMode` — Type of stub
`'NotaStub'` (default) | `'Series'` | `'Shunt'`

Type of stub, specified as one of the following values: 'NotaStub', 'Series', 'Shunt'.

Data Types: double

`Termination` — Stub transmission line termination
`'NotApplicable'` (default) | `'Open'` | `'Short'`

Stub transmission line termination, specified as one of the following values: 'NotApplicable', 'Open', 'Short'.

Data Types: double

Object Functions

`analyze`	Analyze RFCKT object in frequency domain
`calculate`	Calculate specified parameters for rfckt objects or rfdata objects
`circle`	Draw circles on Smith Chart
`extract`	Extract specified network parameters from rfckt object or data object
`listformat`	List valid formats for specified circuit object parameter
`listparam`	List valid parameters for specified circuit object
`loglog`	Plot specified circuit object parameters using log-log scale
`plot`	Plot circuit object parameters on X-Y plane
`plotyy`	Plot parameters of RF circuit or RF data on xy-plane with two Y-axes
`getop`	Display operating conditions
`polar`	Plot specified object parameters on polar coordinates
`semilogx`	Plot RF circuit object parameters using log scale for x-axis
`semilogy`	Plot RF circuit object parameters using log scale for y-axis
`smith`	Plot circuit object parameters on Smith Chart
`write`	Write RF data from circuit or data object to file
`getz0`	Calculate characteristic impedance of RFCKT transmission line object
`read`	Read RF data from file to new or existing circuit or data object
`restore`	Restore data to original frequencies
`getop`	Display operating conditions
`groupdelay`	Group delay of S-parameter object or RF filter object or RF Toolbox circuit object

Examples

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RLCG Transmission Line

Open Live Script

Create an RLCG transmission line using rfckt.rlcgline.

rlcgtx=rfckt.rlcgline('R',0.002,'C',8.8542e-12,'L',1.2566e-6,'G',0.002')

rlcgtx = 
   rfckt.rlcgline with properties:

              Freq: 1.0000e+09
                 R: 0.0020
                 L: 1.2566e-06
                 C: 8.8542e-12
                 G: 0.0020
          IntpType: 'Linear'
        LineLength: 0.0100
          StubMode: 'NotAStub'
       Termination: 'NotApplicable'
             nPort: 2
    AnalyzedResult: []
              Name: 'RLCG Transmission Line'

Algorithms

The analyze method treats the transmission line, which can be lossy or lossless, as a 2-port linear network. It uses the interpolation method you specify in the IntpType property to find the R, L, C, and G values at the frequencies you specify when you call analyze. Then, it calculates the characteristic impedance, Z0, phase velocity, PV, and loss using these interpolated values. It computes the AnalyzedResult property of a stub or as a stubless line using the data stored in the rfckt.rlcgline object properties as follows:

If you model the transmission line as a stubless line, the analyze method first calculates the ABCD-parameters at each frequency contained in the modeling frequencies vector. It then uses the abcd2s function to convert the ABCD-parameters to S-parameters.
The analyze method calculates the ABCD-parameters using the physical length of the transmission line, d, and the complex propagation constant, k, using the following equations:

$\begin{array}{l} A = \frac{e^{k d} + e^{- k d}}{2} \\ B = \frac{Z_{0} * (e^{k d} - e^{- k d})}{2} \\ C = \frac{e^{k d} - e^{- k d}}{2 * Z_{0}} \\ D = \frac{e^{k d} + e^{- k d}}{2} \end{array}$
Z₀ and k are vectors whose elements correspond to the elements of f, the vector of frequencies specified in the analyze input argument freq. Both can be expressed in terms of the resistance (R), inductance (L), conductance (G), and capacitance (C) per unit length (meters) as follows:
$\begin{matrix} Z_{0} = \sqrt{\frac{R + j 2 π f L}{G + j 2 π f C}} \\ k = k_{r} + j k_{i} = \sqrt{(R + j 2 π f L) (G + j 2 π F C)} \end{matrix}$
If you model the transmission line as a shunt or series stub, the analyze method first calculates the ABCD-parameters at the specified frequencies. It then uses the abcd2s function to convert the ABCD-parameters to S-parameters.
When you set the StubMode property to 'Shunt', the 2-port network consists of a stub transmission line that you can terminate with either a short circuit or an open circuit as shown in the following figure.

Z_in is the input impedance of the shunt circuit. The ABCD-parameters for the shunt stub are calculated as:

$\begin{matrix} A = 1 \\ B = 0 \\ C = 1 / Z_{i n} \\ D = 1 \end{matrix}$
When you set the StubMode property to 'Series', the 2-port network consists of a series transmission line that you can terminate with either a short circuit or an open circuit as shown in the following figure.

Z_in is the input impedance of the series circuit. The ABCD-parameters for the series stub are calculated as:

$\begin{matrix} A = 1 \\ B = Z_{i n} \\ C = 0 \\ D = 1 \end{matrix}$

The analyze method uses the S-parameters to calculate the group delay values at the frequencies specified in the analyze input argument freq, as described in the analyze reference page.

References

[1] Ludwig, R. and P. Bretchko, RF Circuit Design: Theory and Applications, Prentice-Hall, 2000

Version History

Introduced in R2009a

rfckt.rlcgline

Description

Creation

Syntax

Description

Properties

AnalyzedResult — Computed S-parameters, noise figure, OIP3, and group delay values rfdata.data object

R — Resistance values per length vector

C — Capacitance values per length vector

Freq — Frequency data M-element vector

G — Conductance values per length vector

IntpType — Interpolation method used in rfckt.rlcgline 'Linear' (default) | 'Spline' | 'Cubic'

L — Inductance values per length vector

LineLength — Physical length of transmission line scalar

Name — Object name 'RLCG Transmission Line' (default) | 1-by-N character array

nport — Number of ports positive integer

StubMode — Type of stub 'NotaStub' (default) | 'Series' | 'Shunt'

Termination — Stub transmission line termination 'NotApplicable' (default) | 'Open' | 'Short'

Object Functions

Examples

RLCG Transmission Line

Algorithms

References

Version History

See Also

`AnalyzedResult` — Computed S-parameters, noise figure, OIP3, and group delay values
`rfdata.data` object

`R` — Resistance values per length
vector

`C` — Capacitance values per length
vector

`Freq` — Frequency data
M-element vector

`G` — Conductance values per length
vector

`IntpType` — Interpolation method used in `rfckt.rlcgline`
`'Linear'` (default) | `'Spline'` | `'Cubic'`

`L` — Inductance values per length
vector

`LineLength` — Physical length of transmission line
scalar

`Name` — Object name
`'RLCG Transmission Line'` (default) | `1-by-N` character array

`nport` — Number of ports
positive integer

`StubMode` — Type of stub
`'NotaStub'` (default) | `'Series'` | `'Shunt'`

`Termination` — Stub transmission line termination
`'NotApplicable'` (default) | `'Open'` | `'Short'`