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rfckt.rlcgline

Passive component or network

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Description

Use therlcglineobject to represent RLCG transmission lines that are characterized by line loss, line length, stub type, and termination.

Creation

Syntax

h = rfckt.rlcgline
h = rfckt.rlcgline(Name,Value)

Description

example

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

h = rfckt.rlcgline(Name,Value)sets properties using one or more name-value pairs. For example,rfckt.rlcgline('LineLenght',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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Computed S-parameters, noise figure, OIP3, and group delay values, specified asrfdata.dataobject.AnalyzedResultis a read-only property. For more information refer, .Algorithms.

Data Types:function_handle

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 is0.

Data Types:double

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 is0.

Data Types:double

Frequency data for the RLCG values, specified as aM-element vector. The values must be positive and correspond to the order of the RLCG values. The default value is1e9.

Data Types:double

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 is0.

Data Types:double

Interpolation method used inrfckt.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

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 is0.

Data Types:double

Physical length of transmission line, specified as a scalar in meters. The default value is0.01.

Data Types:double

Object name, specified as a1-by-Ncharacter array.Nameis a read-only property.

Data Types:char

数量的端口,指定为一个positive integer.nportt is a read-only property. The default value is2.

Data Types:double

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

Data Types:double

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 X-Y 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 forx-axis
semilogy Plot RF circuit object parameters using log scale fory-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 orRF Toolboxcircuit object

Examples

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Open Live Script

Create an RLCG transmission line usingrfckt.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

Theanalyzemethod treats the transmission line, which can be lossy or lossless, as a 2-port linear network. It uses the interpolation method you specify in theIntpTypeproperty to find the R, L, C, and G values at the frequencies you specify when you callanalyze. Then, it calculates the characteristic impedance, Z0, phase velocity, PV, and loss using these interpolated values. It computes theAnalyzedResultproperty of a stub or as a stubless line using the data stored in therfckt.rlcglineobject properties as follows:

  • If you model the transmission line as a stubless line, theanalyzemethod first calculates the ABCD-parameters at each frequency contained in the modeling frequencies vector. It then uses theabcd2sfunction to convert the ABCD-parameters to S-parameters.

    Theanalyzemethod calculates the ABCD-parameters using the physical length of the transmission line,d, and the complex propagation constant,k, using the following equations:

    A = e k d + e − k d 2 B = Z 0 * ( e k d − e − k d ) 2 C = e k d − e − k d 2 * Z 0 D = e k d + e − k d 2

    Z0andkare vectors whose elements correspond to the elements off, the vector of frequencies specified in theanalyzeinput argumentfreq. Both can be expressed in terms of the resistance (R), inductance (L), conductance (G), and capacitance (C) per unit length (meters) as follows:

    Z 0 = R + j 2 π f L G + j 2 π f C k = k r + j k i = ( R + j 2 π f L ) ( G + j 2 π F C )

  • If you model the transmission line as a shunt or series stub, theanalyzemethod first calculates the ABCD-parameters at the specified frequencies. It then uses theabcd2sfunction to convert the ABCD-parameters to S-parameters.

    When you set theStubModeproperty 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.

    2-port network consists of a stub transmission line terminated with either a short circuit or an open circuit

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

    A = 1 B = 0 C = 1 / Z i n D = 1

    When you set theStubModeproperty 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.

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

    A = 1 B = Z i n C = 0 D = 1

Theanalyzemethod uses the S-parameters to calculate the group delay values at the frequencies specified in theanalyzeinput argumentfreq, as described in theanalyzereference page.

References

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

Version History

Introduced in R2009a

See Also

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