ELE4605: Fields & Waves- University of Southern Queensland- Numerical Transmission Line- Engineering Assignment Help

Internal Code: MAS7671

Engineering Assignment Help:

Task: Question 1: Propagation Coefficient A cable has distributed parameters of R, L, C and G, with values as follows: ...have the same characteristics for ?, ?, the absolute value |Zo|, and the phase 6 Zo as shown in Figure 2.3, 2.4, 2.5, and 2.6 (duplicated over page). Using MATLAB, create a program that calculates and plots the value of ?, ?, the absolute value |Zo|, and the phase 6 Zo for a wide range of frequencies. Determine the upper frequency limit and demonstrate that the characteristic curves are as shown in the StudyBook. Include in your report a listing of your program, as well as a discussion (50 words) of your results and where you have determined HF approximations will become suitable. Question 2: Smith Charts A 75 ? RF coaxial line is used to feed an antenna array at a frequency of f MHz. The line insulation is polythene having a dielectric constant of ?r, and the inner diameter of the outer shield is b mm. Unfortunately the antenna is not at all matched to the line, with measurements showing a voltage standing wave ratio of V SW R, with the first voltage minimum occurring d m from the antenna input. Part (a) Calculate: (a) The diameter of the inner conductor ; (b) the wavelength inside the transmission line ; (c) the antenna input impedance using both a Smith chart, and by direct calculation; (d) the antenna voltage reflection coefficient using both a Smith chart, and by direct calculation (20 marks); and (e) the point nearest to the antenna at which the line impedance is purely resistive, and also the value of this impedance using both a Smith chart, and by direct calculation. Part (b) The line is to be broken at the position calculated in Part (e) above and a quarter wave transformer inserted to achieve a match. The transformer is to have the same outer diameter and use the same dielectric as the main line. Calculate: (f) The transformer characteristic impedance; (g) the diameter of the inner conductor ; and (h) the transformer length. Question 3: Time Domain Reflectometry A transmission line between two poorly impedance matched pieces of equipment is created from spare equipment at hand. The equivalent circuit is shown in the above diagram. It has source of internal resistance, ZI , is driving a load, ZL, via a length, d, of lossless 75? coaxial cable, ZO. The source voltage is initially zero and the line is initially uncharged, with ??r = 2.8. Part (a)  If the open circuit source voltage, VI , jumps abruptly from zero to +32.1 volts at t = 0: (i) Calculate the round trip delay; (ii) Calculate the amplitude of the initial step which is launched onto the line; and then (iii) Calculate the final values of both the sending end and receiving end voltages. Part (b)  You are required to create a MATLAB program that: (i) Calculates the first twenty (20×) reflections at each end of the line for t > 0; which then (ii) Plots the resultant waveforms of the sending end and receiving end voltages in their correct time relationship for t > 0. Your program must calculate and display the reflected voltages at each stage of the lattice diagram. Include a listing of your program in your submission.