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Shunt RLC component


Use the shuntrlc class to represent a component as a resistor, inductor, and capacitor connected in a shunt configuration.

The shunt RLC network object is a 2-port network as shown in the following circuit diagram.




h = rfckt.shuntrlc returns a shunt RLC network object whose properties all have their default values. The default object is equivalent to a pass-through 2-port network; i.e., the resistor, inductor, and capacitor are each replaced by a short circuit.

h = rfckt.shuntrlc('R',Rvalue,'L',Lvalue,'C',Cvalue) sets properties using one or more name-value pairs. You can specify multiple name-value pairs. Enclose each property name in a quote


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

Data Types: function_handle

Resistance value, specified as a positive scalar in ohms. The default value is 0.

Data Types: double

Capacitance value, specified as a positive scalar in farads. The default value is 0.

Data Types: double

Inductance value, specified as a positive scalar in henries. The default value is 'Inf'.

Data Types: double

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

Data Types: char

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

Data Types: double

Object Functions

analyzeAnalyze RFCKT object in frequency domain
calculateCalculate specified parameters for rfckt objects or rfdata objects
circleDraw circles on Smith Chart
extractExtract specified network parameters from rfckt object or data object
listformatList valid formats for specified circuit object parameter
listparamList valid parameters for specified circuit object
loglogPlot specified circuit object parameters using log-log scale
plotPlot specified circuit object parameters on X-Y plane
plotyyPlot parameters of RF circuit or RF data on X-Y plane with Y-axes on both left and right sides
getopDisplay operating conditions
polarPlot specified object parameters on polar coordinates
semilogxPlot RF circuit object parameters using log scale for x-axis
semilogyPlot RF circuit object parameters using log scale for y-axis
smithPlot circuit object parameters on Smith chart
writeWrite RF data from circuit or data object to file
getz0Get characteristic impedance of transmission line object
readRead RF data from file to new or existing circuit or data object
restoreRestore data to original frequencies
getopDisplay operating conditions
groupdelayGroup delay of S-parameter object or RF filter object or RF Toolbox circuit object


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This example creates a shunt LC resonator and examines its frequency response. It first creates the circuit object and then uses the analyze method to calculate its frequency response. The plot is in decibels(dB).

h = rfckt.shuntrlc('L',4.7e-5,'C',2.2e-10);
ax = gca;
ax.XScale = 'log';

Figure contains an axes. The axes contains an object of type line. This object represents S_{21}.

The example then plots the phase, in degrees:

ax = gca;
ax.XScale = 'log';

Figure contains an axes. The axes contains an object of type line. This object represents S_{21}.


The analyze method computes the S-parameters of the AnalyzedResult property using the data stored in the rfckt.shuntrlc object properties by first calculating the ABCD-parameters for the circuit, and then converting the ABCD-parameters to S-parameters using the abcd2s function. For this circuit, A = 1, B = 0, C = Y, and D = 1, where


and ω = 2πf.

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.


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

Introduced in R2009a