Create and analyze a two-wire network object.

tx1=rfckt.twowire('Radius',7.5e-4); analyze(tx1,1.9e9)

ans = rfckt.twowire with properties: Radius: 7.5000e-04 Separation: 0.0016 MuR: 1 EpsilonR: 2.3000 LossTangent: 0 SigmaCond: Inf LineLength: 0.0100 StubMode: 'NotAStub' Termination: 'NotApplicable' nPort: 2 AnalyzedResult: [1x1 rfdata.data] Name: 'Two-Wire Transmission Line'

This example shows how to analyze an RF amplifier at different reference impedances.

Assign the load and the source impedances.

zl = 50 - 50*1i; zs = 200 + 50*1i;

Create two amplifier circuits with the same Touchstone® file.

circuit50 = read(rfckt.amplifier,'default.s2p'); circuit75 = read(rfckt.amplifier,'default.s2p');

Analyze the amplifier circuits at two different reference impedance,50and75ohms.

analyzed_circuit50 = analyze(circuit50, circuit50.NetworkData.Freq, zl, zs,50); analyzed_circuit75 = analyze(circuit75, circuit50.NetworkData.Freq, zl, zs,75);

Plot S21 for the two amplifier circuits.

figure(30); plot(analyzed_circuit50,'S21') holdon; plot(analyzed_circuit75,'S21')

Note that in this example two amplifier circuits derived from a same touchstone file at two different reference impedances produce two different S21 plot. This is because, the S-parameters are only dependent on the reference impedance,z0, and not on the source impedance,zsor the load impedance,zl.

The analyze function storeszsandzlin the amplifier and these impedances are used when azsandzldependent parameter is calculated. For example, plot transducer gain,Gtof the two amplifier circuits.

figure(20); plot(analyzed_circuit50,'Gt') holdon; plot(analyzed_circuit75,'Gt')

Note thatGtis dependent onzs,zl, andz0. Hence for the two amplifier circuits derived from a same touchstone file with samezsandzlatz0of50and75ohms yields the sameGt.