rfelement

Generic RF element object

Description

Use the rfelement object to create a generic RF element. An RF element is a 2–port RF circuit object. You can use this element in the rfbudget object and the circuit object.

Creation

Syntax

rfel = rfelement

rfel = rfelement(Name,Value)

Description

rfel = rfelement creates an RF element object with default property values.

rfel = rfelement(Name,Value) sets properties using one or more name-value pairs. You can specify multiple name-value pairs. Enclose each property name in a quote.

Properties

Name — Name given to identify RF element

'RFelement' (default) | character vector

Name given to identify rf element, specified as a character vector. All names must be valid MATLAB^® variable names.

Example: 'Name','rfel'

Example: rfel.Name = 'rfel'

Gain — Available power gain

0 (default) | scalar

Available power gain, specified as a scalar in dB.

Example: 'Gain',10

Example: rfel.Gain = 10

NF — Noise figure

0 (default) | real finite nonnegative scalar

Noise figure, specified as a real finite nonnegative scalar dB.

Example: 'NF',-10

Example: rfel.NF = -10

OIP2 — Second -order output-referred intercept point

Inf (default) | real scalar

Second -order output-referred intercept point, specified as a real scalar in dBm.

Example: 'OIP2',8

Example: amplifier.OIP2 = 8

OIP3 — Third -order output-referred intercept point

Inf (default) | real scalar

Third -order output-referred intercept point, specified as a real scalar in dBm.

Example: 'OIP3',10

Example: amplifier.OIP3 = 10

Zin — Input impedance

50 (default) | positive real part finite scalar

Input impedance, specified as a positive real part finite scalar in Ohms. You can also use a complex value with a positive real part.

Example: 'Zin',40

Example: rfel.Zin = 40

Zout — Output impedance

50 (default) | positive real part finite scalar

Output impedance, specified as a scalar in Ohms. You can also use a complex value with a positive real part.

Example: 'Zout',40

Example: rfel.Zout = 40

NumPorts — Number of ports

2 (default) | scalar integer

Number of ports, specified as a scalar integer. This property is read-only.

'Terminals' — Names of port terminals

{'p1+' 'p2+' 'p1-' 'p2-'} (default) | cell vector

Names of port terminals, specified as a cell vector. This property is read-only.

Object Functions

clone

Create copy of existing circuit element or circuit object

Examples

RF Element

Create an rfelement object with a gain of 10 dB, noise figure of 3 dB, and OIP3 (output third-order intercept) of 2 dBm.

r = rfelement('Gain',10,'NF',3,'OIP3',2)

r = 
  rfelement: RF element

         Name: 'RFelement'
         Gain: 10
           NF: 3
         OIP2: Inf
         OIP3: 2
          Zin: 50
         Zout: 50
     NumPorts: 2
    Terminals: {'p1+'  'p2+'  'p1-'  'p2-'}

RF Element Circuit

Create an rf element with a gain of 4 dB. Create another rf element with an output third-order intercept(OIP3) of 13 dBm.

rfel1 = rfelement('Gain',4);
rfel2 = rfelement('OIP3',13);

Build a 2-port circuit using the above defined rf elements.

c = circuit([rfel1 rfel2])

c = 
  circuit: Circuit element

    ElementNames: {'RFelement'  'RFelement_1'}
        Elements: [1x2 rfelement]
           Nodes: [0 1 2 3]
            Name: 'unnamed'
        NumPorts: 2
       Terminals: {'p1+'  'p2+'  'p1-'  'p2-'}

RF Budget Analysis of Series of RF Elements

Create an amplifier with a gain of 4 dB.

a = amplifier(Gain=4);

Create a modulator with an OIP3 of 13 dBm.

m = modulator(OIP3=13);

Create an N-port element using passive.s2p.

n = nport('passive.s2p');

Create an RF element with a gain of 10 dB.

r = rfelement(Gain=10);

Calculate the RF budget of a series of RF elements at an input frequency of 2.1 GHz, an available input power of –30 dBm, and a bandwidth of 10 MHz.

b = rfbudget([a m r n],2.1e9,-30,10e6)

b = 
  rfbudget with properties:

               Elements: [1x4 rf.internal.rfbudget.Element]
         InputFrequency: 2.1 GHz
    AvailableInputPower: -30 dBm
        SignalBandwidth:  10 MHz
                 Solver: Friis      
             AutoUpdate: true

   Analysis Results
        OutputFrequency: (GHz) [  2.1    3.1    3.1     3.1]
            OutputPower: (dBm) [  -26    -26    -16   -20.6]
         TransducerGain: (dB)  [    4      4     14     9.4]
                     NF: (dB)  [    0      0      0  0.1392]
                   IIP2: (dBm) []                           
                   OIP2: (dBm) []                           
                   IIP3: (dBm) [  Inf      9      9       9]
                   OIP3: (dBm) [  Inf     13     23    18.4]
                    SNR: (dB)  [73.98  73.98  73.98   73.84]

Type the show command at the command window to display the analysis in the RF Budget Analyzer app.

show(b)

Version History

Introduced in R2017a

R2023b: Recommended over rfdata.ip3

rfelement is recommended over rfdata.ip3 because it enables you to:

• Create a generic RF element with third-order intercept points.

• Build a circuit object with a generic RF element.

• Model an amplifier in an RF chain created using an rfbudget object or the RF Budget Analyzer app, and then export this element to RF Blockset™ or to rfsystem System object™ for circuit envelope analysis.