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CHAPTER 4 - Impedance Matching 196 The simulation equivalent of the circuit of Figure 4.6-1 is shown in Figure 4.6-2. Corresponding elements in these two figures are shown by frames of the same type and colour. First and foremost let us talk about the "PORT" element in Figure 4.6-2. This element represents a signal generator, with internal impedance specified by the parameter 'Z', which is also able to measure the power that flows out of its terminal and the power that is reflected back into it. Its circuital equivalent is shown in the dashed frame in Figure 4.6-1. When we have more than one port, some of the ports may simply behave as an impedance equal to 'Z' ohm furnished with power meters as shown in Figure 4.6-3. The latter are defined as 'passive' ports whereas and the former as 'active' ports. Figure 4.6-3 Passive port in MWO The second element if Figure 4.6-2 represents a transmission of line whose length is specified in terms of its electrical length 'TLIN'. For this element we need to specify the characteristic impedance (Z0), which we have chosen to be the same as that of PORT 1, the electrical length (EL) in degrees (20ι in this case) and the frequency F0 which is used to calculate the electrical EL 33 . Finally we have the load impedance ZL, which we have implemented with an element called 'IMPED' 34 . This element allows us to specify explicitly the real and imaginary parts of a complex impedance. Figure 4.6-4 Measuring reflection coefficient in MWO 33 Remember that the electrical length θ of a line is equal to , where is the physical length of the line 34 Sometimes it may be advantageous to use the 'ADMIT' element in MWO, which may be used to simulate any arbitrary admittance expressed in Cartesian form ǡθ (l) θ (EL) Conquer Radio Frequency 196 www.cadence.com/go/awr

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