RF Circuit Objects

Overview of RF Circuit Objects

RF Toolbox™ software uses circuit (rfckt) objects to represent the following components:

Circuit components such as amplifiers, transmission lines, and ladder filters
RLC network components
Networks of RF components

The toolbox represents each type of component and network with a different object. You use these objects to analyze components and networks in the frequency domain.

Components Versus Networks

You define component behavior using network parameters and physical properties.

To specify an individual RF component:

Construct a circuit object to represent the component.
Specify or import component data.

You define network behavior by specifying the components that make up the network. These components can be either individual components (such as amplifiers and transmission lines) or other networks.

To specify an RF network:

Build circuit objects to represent the network components.
Construct a circuit object to represent the network.
Note
This object defines how to connect the network components. However, the network is empty until you specify the components that it contains.
Specify, as the Ckts property of the object that represents the network, a list of components that make up the network.

These procedures are illustrated by example in Model Cascaded Network.

Available Components and Networks

To create circuit objects that represent components, you use constructors whose names describe the components. To create circuit objects that represent networks, you use constructors whose names describe how the components are connected together.

The following table lists the available rfckt object constructors and describes the components or networks the corresponding objects represent. For more information on a particular object, follow the link in the table to the reference page for that object.

Constructor	Description
`rfckt.amplifier`	Amplifier, described by an `rfdata` object
`rfckt.cascade`	Cascaded network, described by the list of components and networks that comprise it
`rfckt.coaxial`	Coaxial transmission line, described by dimensions and electrical characteristics
`rfckt.cpw`	Coplanar waveguide transmission line, described by dimensions and electrical characteristics
`rfckt.datafile`	General circuit, described by a data file
`rfckt.delay`	Delay line, described by loss and delay
`rfckt.hybrid`	Hybrid connected network, described by the list of components and networks that comprise it
`rfckt.hybridg`	Inverse hybrid connected network, described by the list of components and networks that comprise it
`rfckt.lcbandpasspi`	LC bandpass pi network, described by LC values
`rfckt.lcbandpasstee`	LC bandpass tee network, described by LC values
`rfckt.lcbandstoppi`	LC bandstop pi network, described by LC values
`rfckt.lcbandstoptee`	LC bandstop tee network, described by LC values
`rfckt.lchighpasspi`	LC highpass pi network, described by LC values
`rfckt.lchighpasstee`	LC highpass tee network, described by LC values
`rfckt.lclowpasspi`	LC lowpass pi network, described by LC values
`rfckt.lclowpasstee`	LC lowpass tee network, described by LC values
`rfckt.microstrip`	Microstrip transmission line, described by dimensions and electrical characteristics
`rfckt.mixer`	Mixer, described by an `rfdata` object
`rfckt.parallel`	Parallel connected network, described by the list of components and networks that comprise it
`rfckt.parallelplate`	Parallel-plate transmission line, described by dimensions and electrical characteristics
`rfckt.passive`	Passive component, described by network parameters
`rfckt.rlcgline`	RLCG transmission line, described by RLCG values
`rfckt.series`	Series connected network, described by the list of components and networks that comprise it
`rfckt.seriesrlc`	Series RLC network, described by RLC values
`rfckt.shuntrlc`	Shunt RLC network, described by RLC values
`rfckt.twowire`	Two-wire transmission line, described by dimensions and electrical characteristics
`rfckt.txline`	General transmission line, described by dimensions and electrical characteristics

Circuit Object Methods

The following table lists the methods of the circuit objects, the types of objects on which each can act, and the purpose of each method.

Method	Types of Objects	Purpose
`analyze`	All circuit objects	Analyze a circuit object in the frequency domain.
`calculate`	All circuit objects	Calculate specified parameters for a circuit object.
`copy`	All circuit objects	Copy a circuit or data object.
`extract`	All circuit objects	Extract specified network parameters from a circuit or data object, and return the result in an array.
`getdata`	All circuit objects	Get data object containing analyzed result of a specified circuit object.
`getz0`	`rfckt.txline`, `rfckt.rlcgline`, `rfckt.twowire`, `rfckt.parallelplate`, `rfckt.coaxial`, `rfdata.microstrip`, `rfckt.cpw`	Get characteristic impedance of a transmission line.
`listformat`	All circuit objects	List valid formats for a specified circuit object parameter.
`listparam`	All circuit objects	List valid parameters for a specified circuit object.
`loglog`	All circuit objects	Plot specified circuit object parameters using a log-log scale.
`plot`	All circuit objects	Plot the specified circuit object parameters on an X-Y plane.
`plotyy`	All circuit objects	Plot the specified object parameters with y-axes on both the left and right sides.
`polar`	All circuit objects	Plot the specified circuit object parameters on polar coordinates.
`read`	`rfckt.datafile`,`rfckt.passive`,`rfckt.amplifier`,`rfckt.mixer`	Read RF data from a file to a new or existing circuit object.
`restore`	`rfckt.datafile`,`rfckt.passive`,`rfckt.amplifier`,`rfckt.mixer`	Restore data to original frequencies of `NetworkData` for plotting.
`semilogx`	All circuit objects	Plot the specified circuit object parameters using a log scale for the X-axis
`semilogy`	All circuit objects	Plot the specified circuit object parameters using a log scale for the Y-axis
`smith`	All circuit objects	Plot the specified circuit object parameters on a Smith chart.
`write`	All circuit objects	Write RF data from a circuit object to a file.
`smithplot`	All circuit objects	Plot measurement data on Smith chart