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RF Electronics Chapter 2: Computer Simulation Page 38 2022, C. J. Kikkert, James Cook University, ISBN 978-0-6486803-9-0. The data in table 2.2 is used in a new circuit, by right clicking on Circuit Schematics and selecting New Schematic and giving that a suitable name like "Measured_Ckt". Select Draw Add Subcircuit and for the Subcircuit select the Measurements Touchstone file. Add ports to result in the circuit shown in figure 2.47. Table 2.2. Bandpass T, S parameters of figure 2.45 when Port Z=50 Ω. !1 2 3 4 5 6 7 8 9 #MHz S RI !Freq S(1,1) (Real) (Imag) S(2,1) (Real) (Imag) S(1,2) (Real) (Imag) S(2,2) (Real) (Imag) 50 -0.243196 -0.731472 0.59059 0.130582 0.59059 0.130582 0.550605 -0.561518 60 -0.375925 -0.65411 0.624213 0.0449708 0.624213 0.0449708 0.484718 -0.598862 70 -0.47541 -0.575551 0.634624 -0.0349784 0.634624 -0.0349784 0.425575 -0.633207 80 -0.552339 -0.499376 0.628902 -0.10684 0.628902 -0.10684 0.370205 -0.66539 90 -0.613449 -0.426228 0.61193 -0.170042 0.61193 -0.170042 0.316886 -0.695395 100 -0.662903 -0.355774 0.587119 -0.224755 0.587119 -0.224755 0.264712 -0.722954 110 -0.703262 -0.287473 0.556924 -0.271444 0.556924 -0.271444 0.213273 -0.747795 120 -0.736122 -0.220851 0.523162 -0.310684 0.523162 -0.310684 0.162454 -0.769717 130 -0.762495 -0.155588 0.487214 -0.343089 0.487214 -0.343089 0.112306 -0.788613 140 -0.783052 -0.0915112 0.450145 -0.369279 0.450145 -0.369279 0.0629657 -0.804466 150 -0.79827 -0.0285797 0.412785 -0.38986 0.412785 -0.38986 0.0146048 -0.817331 160 -0.808518 0.0331546 0.375778 -0.405423 0.375778 -0.405423 -0.0325988 -0.827327 170 -0.814116 0.0935747 0.339618 -0.416533 0.339618 -0.416533 -0.0784796 -0.834611 180 -0.81536 0.152526 0.30468 -0.423723 0.30468 -0.423723 -0.122895 -0.839373 190 -0.812541 0.209837 0.271237 -0.427495 0.271237 -0.427495 -0.16573 -0.84182 200 -0.805953 0.265335 0.239481 -0.428314 0.239481 -0.428314 -0.206899 -0.842168 210 -0.795895 0.31886 0.209536 -0.426606 0.209536 -0.426606 -0.246341 -0.840633 220 -0.782667 0.37027 0.181472 -0.422762 0.181472 -0.422762 -0.284025 -0.837429 230 -0.766573 0.419448 0.155312 -0.417133 0.155312 -0.417133 -0.319939 -0.832757 240 -0.747909 0.466301 0.131047 -0.410032 0.131047 -0.410032 -0.354093 -0.826812 250 -0.726969 0.510764 0.108637 -0.40174 0.108637 -0.40174 -0.386513 -0.81977 Sometimes one needs to develop a circuit model corresponding to measured data. In most cases, one has to develop a circuit schematic based on physical properties of frequency behaviour. To develop a Bandpass T matching network model of the measured data of table 2.2, the circuit is known, but component values are not known. To develop a model of the network, a suitable circuit diagram is developed, with trial guesses for the component values. As shown in figure 2.48, the components are guessed to be 1 pF for the capacitors and 1 nH for the inductor. A value of 100 is used for the initial Q values. Figure 2.48. Bandpass T matching network initial guess. The model needs to be tuned or optimised to ensure its S parameters match the measurements for all S parameters and all frequencies. To achieve this error equations are produced, like the equations 2.5 shown below for S 11 . RF Electronics: Design and Simulation 38 www.cadence.com/go/awr