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rfplot

Plot input reflection coefficient and transducer gain of matching network

Description

rfplot(mnobj) plots the input reflection coefficient and transducer gain of the matching network when cascaded between source and load impedances. This plot compares the actual performance of the network against the performance goals.

rfplot(mnobj,frequencylist) plots using values calculated at each frequency in the frequencylist.

example

rfplot(mnobj,frequencylist,circuitindices) plots performances of matching networks specified in the circuitindices.

hline = rfplot(mnobj,frequencylist,circuitindices) returns a cell array of line handle vectors, one cell for each circuit plotted.

Examples

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Create a dipole antenna and create the S-parameters of the antenna. This example requires Antenna Toolbox.

d       = dipole('Length', 0.103, 'Width',0.0022);
freq    = linspace(0.5e9,2.5e9,1001);
sd      = sparameters(d, freq);

Alternatively, load S-Parameters from the MAT file

% load('sparams_dipole.mat')

Create a matching network from the S-parameters.

n = matchingnetwork('LoadImpedance',sd,'Components',3,...
    'LoadedQ',7,'CenterFrequency',2e9);

Get the evaluation parameters of the network.

t = getEvaluationParameters(n)
t=1×6 table
    Parameter    Comparison     Goal               Band               Weight       Source    
    _________    __________    ______    _________________________    ______    _____________

     {'Gt'}        {'>'}       {[-3]}    {[1.8571e+09 2.1429e+09]}    {[1]}     {'Automatic'}

Plot the reflection coefficient and transducer gain of the matching network circuit 1 , at a frequency range of 1 GHz to 2.5 GHz.

rfplot(n, (1e9:0.001e9:2.5e9),1);

Figure Circuit 1 contains an axes object. The axes object with title Performance for Circuit 1 ('auto_6') (Passed) contains 3 objects of type line, rectangle. These objects represent Circuit 1: |gammain|, dB, Circuit 1: |Gt|, dB.

Add a new evaluation parameter to compare the transducer gain to have a cut-off of less than -10 dB. Use a frequency range of 0.5 GHz to 1.5 GHz. Plot the comparisons.

n = addEvaluationParameter(n, 'Gt', '<', -10, [0.5e9 1.5e9], 1);
t = getEvaluationParameters(n)
t=2×6 table
    Parameter    Comparison     Goal                Band               Weight          Source      
    _________    __________    _______    _________________________    ______    __________________

     {'Gt'}        {'>'}       {[ -3]}    {[1.8571e+09 2.1429e+09]}    {[1]}     {'Automatic'     }
     {'Gt'}        {'<'}       {[-10]}    {[ 500000000 1.5000e+09]}    {[1]}     {'User-specified'}

rfplot(n, (1e9:0.001e9:2.5e9),1);

Figure Circuit 1 contains an axes object. The axes object with title Performance for Circuit 1 ('auto_8') (Passed) contains 4 objects of type line, rectangle. These objects represent Circuit 1: |gammain|, dB, Circuit 1: |Gt|, dB.

Clear evaluation parameters.

n = clearEvaluationParameter(n,1);
t = getEvaluationParameters(n)
t=1×6 table
    Parameter    Comparison     Goal                Band              Weight          Source      
    _________    __________    _______    ________________________    ______    __________________

     {'Gt'}        {'<'}       {[-10]}    {[500000000 1.5000e+09]}    {[1]}     {'User-specified'}

Input Arguments

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Matching network, specified as a matchingnetwork object.

Data Types: char | string

Frequency values at which to plot the performance of the matching network, specified as a vector with each element in Hz.

Data Types: double

Index of the matching network circuit, specified as a vector or scalar.

Data Types: double

Output Arguments

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Line handle of circuit plotted, returned as a cell array with one cell for each circuit plotted.

Introduced in R2019a