rfckt.seriesrlc

Series RLC component

Description

Use the seriesrlc class to represent a component as a resistor, inductor, and capacitor connected in series.

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

Creation

Syntax

h = rfckt.seriesrlc

h = rfckt.seriesrlc('R',Rvalue,'L',Lvalue,'C',Cvalue)

Description

h = rfckt.seriesrlc returns a series 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.seriesrlc('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

Properties

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. Analyzed Result is a read-only property. For more information refer, Algorithms.

Data Types: function_handle

R — Resistance value

positive scalar

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

Data Types: double

C — Capacitance value

positive scalar

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

Data Types: double

L — Inductance value

positive scalar

Inductance value, specified as a positive scalar in henries. The default value is 0.

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

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 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

Frequency Response of an LC Resonator

This example creates a series LC resonator and examines its frequency response. It first creates the circuit object and then uses the analyze method to calculate its frequency response. Finally, it plots the results - first, the magnitude in decibels (dB):

h = rfckt.seriesrlc('L',4.7e-5,'C',2.2e-10);
analyze(h,logspace(4,8,1000));
plot(h,'s21','dB')
ax = gca;
ax.XScale = 'log';

The example then plots the phase, in degrees:

figure
plot(h,'s21','angle')
ax = gca;
ax.XScale = 'log';

Algorithms

The analyze method computes the S-parameters of the AnalyzedResult property using the data stored in the rfckt.seriesrlc 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 = Z, C = 0, and D = 1, where

$$Z=\frac{-LC{\omega }^2+jRC\omega +1}{jC\omega }$$

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.

References

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

Version History

Introduced in R2009a