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:

  1. Construct a circuit object to represent the component.

  2. 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:

  1. Build circuit objects to represent the network components.

  2. 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.

  3. 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 a Cascaded RF 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.

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