Question

Problem 7. Transmission Lines The figure below shows a transmission line with a characteristic impedance Z,-50 Ω, connected to a single frequency generator with an internal impedance R,-50 C (not shown), and terminated in a purely resistive load RL 50 2. At the frequency of the generator, the wavelength of the transmission line is λ = 2 m. At a distance dl-1.25 m away from the load, a shorted stub is connected via a tee. The length of the stub can be freely adjusted from 0 to infinity (0) What is the equivalent input impedance Zld at any distance d di from the load? (2) On the Smith chart (schematically shown at lower left corner of the figure; used here to map impedance to reflection coefficient and vice versa, as on the screen of a network analyzer), draw the locus of the normalized equivalent input impedance 2(di)- Zd)/Zo when the stub length is adjusted. Notice that Zdi) is the total impedance at di, including the stub in parallel to the main transmission line. (3) As shown in the figure, d 0.5 m. Draw on the Smith chart (use the same chart) the locus of the normalized equivalent input impedance z(ditd2)Ztdh/Zo when the stub length is adjusted (4) When the stub length is adjusted to exactly a quarter of the wavelength on the stub and the incident power to the system is 10 mW, what is the power reflected back to the generator? d2 50 Ω 180 0.2 102.0-3.0-5.0-10.0 0 Adjustable

answer number 3 and 4

Answer 1

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