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Unformatted text preview: ECE 3030: Electromagnetic Fields and Waves Fall 2009 WORKSHOP 10 INSTRUCTOR NOTES: Bounce Diagrams, Waveguides Reminder: Date: Thursday 11/5 1. Problem 13.34: Consider the switching transient at the source end of the follow- ing transmission line circuit. The source voltage equals 2 volts and was switched on = 50 o Z ) ( t V s 150 = z "- = z z 150 Figure 1: Transmission line with switched source and unmatched load. at time t =- . At time t = 0, the switch at the source end is closed, shorting out the source. Plot the voltage V ( z = 0 ,t ) across the load resistor for the time interval t 9 / 2 v . Solution: Here a source is shorted that had been driving a transmission line for a long time. The reflection coefficients are S =- 1 and L = 1 / 2. Initially there is 1 V across the load. Then V 1+ =- 1 V, leaving zero on the line, but at the load a reflection occurs with V 1- =- 1 / 2 V, leaving- 1 / 2 V across the load. Then V 1- reflects at the shorting switch giving V 2+ = +1 / 2 V, which in turn reflects off the load leaving +1 / 4 V across the load. The plot should have +1 V from t = 0 until t = /v at which time it changes to -1/2 V. At t = 3 /v it changes to +1/4 V until t = 5 /v , etc. Source Load V1+, I1+ V1-, I1- V2+, I2+ V3+, I3+ V2-, I2- V3-, I3- Figure 2: Bounce diagram. CORNELL UNIVERSITY c WES SWARTZ (09/8/14) 101 ECE 3030: Electromagnetic Fields and Waves Fall 2009 WORKSHOP 10 INSTRUCTOR NOTES: Bounce Diagrams, Waveguides 2. Problem 15.20 Consider the following integrated optical waveguide on a Silicon substrate. As long as the width W of the waveguide is much larger than its height h , the Silicon Substrate Silicon Dioxide S i l i c o n W h Figure 3: Silicon slab waveguide....
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This note was uploaded on 01/16/2010 for the course ECE 3030 at Cornell University (Engineering School).