Plot cumulative RF budget result versus cascade input frequency



rfplot(rfobj,str) plots the RF budget result specified by STR versus a range of input frequencies. The input frequencies are applied to the cascade of elements in the RF budget object, rfobj.

Cumulative (that is, terminated subcascade) results are automatically computed to show the variation of the RF budget result through the entire design.

rfplot(rfobj) plots the magnitude response of S-Parameters, S21 for the cascaded budget object, rfobj.

rfplot(rfobj,m,n) plots the magnitude response of S-Parameters, Smn (S11, S12, S21 , or S22) for the cascaded budget object, rfobj.


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Create an RF system.

Create an RF bandpassfilter using the Touchstone file RFBudget_RF.

f1 = nport('RFBudget_RF.s2p','RFBandpassFilter');

Create an amplifier with a gain of 11.53 dB, a noise figure (NF)of 1.53 dB, and an output third-order intercept (OIP3) of 35 dBm.

a1 = amplifier('Name','RFAmplifier','Gain',11.53,'NF',1.53,'OIP3',35);

Create a demodulator with a gain of -6 dB, a NF of 4 dB, and an OIP3 of 50 dBm.

d = modulator('Name','Demodulator','Gain',-6,'NF',4,'OIP3',50, ...

Create an IF bandpassfilter using the Touchstone file RFBudget_IF.

f2 = nport('RFBudget_IF.s2p','IFBandpassFilter');

Create an amplifier with a gain of 30 dB, a NF of 8 dB, and an OIP3 of 37 dBm.

a2 = amplifier('Name','IFAmplifier','Gain',30,'NF',8,'OIP3',37);

Calculate the RF budget of the system using an input frequency of 2.1 GHz, an input power of -30 dBm, and a bandwidth of 45 MHz.

b = rfbudget([f1 a1 d f2 a2],2.1e9,-30,45e6)
b = 
  rfbudget with properties:

               Elements: [1x5 rf.internal.rfbudget.Element]
         InputFrequency: 2.1 GHz
    AvailableInputPower: -30 dBm
        SignalBandwidth:  45 MHz
                 Solver: Friis      
             AutoUpdate: true

   Analysis Results
        OutputFrequency: (GHz) [   2.1    2.1   0.07    0.07   0.07]
            OutputPower: (dBm) [-31.53    -20    -26  -27.15  2.847]
         TransducerGain: (dB)  [-1.534  9.996  3.996   2.847  32.85]
                     NF: (dB)  [ 1.533  3.064  3.377   3.611  7.036]
                   IIP2: (dBm) []                                   
                   OIP2: (dBm) []                                   
                   IIP3: (dBm) [   Inf     25  24.97   24.97  4.116]
                   OIP3: (dBm) [   Inf     35  28.97   27.82  36.96]
                    SNR: (dB)  [ 65.91  64.38  64.07   63.83  60.41]

Plot the available output power.


Plot the transducer gain.


Plot sparameters of RF System on a Smith Chart and a Polar plot

s = smithplot(b,1,1,'GridType','ZY'); 

p = polar(b,2,1); 

Input Arguments

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Cumulative RF budget results, specified as an object.

Example: rfplot(rfobj,'Pout') where rfobj is created using rfbudget object.

STR values, specified as one of the following:

  • 'Pout' - Available output power (dBm)

  • 'GainT' - Transducer gain (dB)

  • 'NF' - Noise Figure (dB)

  • 'OIP3' - Output Third-Order Intercept (dBm)

  • 'IIP3' - Input Third-Order Intercept (dBm)

  • 'SNR' - Signal-to-Noise Ratio (dB)

  • 'Sparameters' - S - Parameters S21 magnitude response (dB)

Example: rfplot(rfobj,'Pout') where 'Pout' is the available output power of an RF system obtained from the RF budget analysis.

Introduced in R2017b