RF System Design Using rfckt Objects

Design an RF system using RF Toolbox™ rfckt objects.

Create RF and IF bandpass filters using rfckt.passive objects.

fi1 = read(rfckt.passive,'RFBudget_RF.s2p');
fi2 = read(rfckt.passive,'RFBudget_IF.s2p');

Create RF and IF amplifiers by specifying an rfdata.network object as an input to the rfckt.amplifier object.

ai1 = rfckt.amplifier('NetworkData', ...
    rfdata.network('Type','S','Freq',2.1e9,'Data',[0,0;3.98,0]), ...
    'NoiseData',2,'NonlinearData',35);
ai2 = rfckt.amplifier('NetworkData', ...
    rfdata.network('Type','S','Freq',2.1e9,'Data',[0,0;31.66,0]), ...
    'NoiseData',8,'NonlinearData',37);

Create a demodulator and microstrip transmission line with the specified parameters using the rfckt.mixer and rfckt.microstrip objects, respectively. In this example, the rfdata.network object used in rfckt.amplifier and rfckt.mixer are used to set the gain of the amplifier and the mixer in linear scale.

mi1 = rfckt.mixer('NetworkData', ...
    rfdata.network('Type','S','Freq',2.1e9,'Data',[0,0;0.501,0]),...
    "MixerType",'Downconverter','FLO',2.03e9,'NoiseData',4,'NonlinearData',50);
tx1 = rfckt.microstrip('Thickness',0.0075e-6);

Cascade the circuit using the rfckt.cascade object.

c = rfckt.cascade('Ckts',{fi1 ai1 mi1 fi2 ai2 tx1});

Analyze the cascaded circuit and plot the 3-D S21 plot.

analyze(c,linspace(2.08e9,2.12e9,100));
plot(c,'budget','s21')

Plot the magnitude of the S21 parameter for the cascade at stage 6.

plot(c,'s21','db')
hold on;
plot(c,'s11','db')

For more information on how to analyze and visualize RF components in the frequency-domain, see Analyze and Plot RF Components.