EE 172 Mid-Term 1 Dr. Ray Kwok Name : __________________________________________________________________________ 1) (a) Calculate YL, Yin, Γin and VSWR (in the 20 Ω line) at 159.1 MHz for the circuit below with a load impedance ZL = 40 Ω. (b) Repeat the problem on a Smith Chart and verify Yin and VSWR are consistence with part (a). ZL Yin ZO=50Ω 20Ω 0.1λ 25 pF 100Ω 0.125λEE 172 Mid-Term 1 Dr. Ray Kwok 2) A 3-port device is characterized by the S-parameters shown here. a) Is this a symmetrical network? Reciprocal? Lossless? b) If port-2 is left open, and port-3 is terminated with a 100-Ω resistor, how much power (in Watt) is being reflected if 30 dBm of RF signal at 1 GHz is injected in port-1? −−=0jjj01j1021)S(EE 172 Mid-Term 1 Dr. Ray Kwok Z, b 3) (a) Derive the Y-matrix for an ideal transmission line with characteristic impedance of Z and length b, using the voltage and current wave definition with V+ and V- amplitudes. (b) An ideal transmission line can also be expressed in terms of characteristic inductance and capacitance. Use this definition and network shown to write down the Y-matrix. (c) Compare the results from (a) and (b). How is the characteristic impedance Z related to L and
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