ECE 540 Midterm II

February 27, 1998

 

Open Notes, Open Book

 

Name ______________________________________

 

1. (25 points) Given a WR___ rectangular waveguide with dimensions a= and b= filled with teflon ( e r = 2.33, s = 0, m r = 1.0).

 

  1. Find the first four propagating modes. Specify their cutoff frequencies, and whether they are TEM, TE, or TM.

    2.  

  2. Suppose the waveguide is excited in such a way so that only the TE10 and TM10 modes are excited. Write an expression for the electric field in the waveguide as a function of x,y,z,t. Specify the values of any variables you can, and explain the meanings of any variables you cannot specify.

    3.  

  3. A broad band pulse made up of frequencies ranging from DC to ______ GHz is excited in this waveguide. Describe what will happen to the pulse. Discuss which frequencies will propagate in what modes, the velocity of propagation, and possible sources of attenuation.

 

 

2. (25 points) Find the S-parameters of the following 2-port network at 1 GHz. The circuit is connected to 50-ohm lines. There are several ways to solve this problem. You may use any method you wish.

 

 

3. (25 points) A two-port network has the following S-parameters relative to 50 ohms:

 

 

  1. If the voltage input to port 1 is 1Volt, and the second port is matched, how much voltage comes out of ports 1 and 2?

    2.  

  2. If the voltage input to port 1 is 1Volt, and the second port is connected to a 175 ohm load, how much power is delivered to the load?

 

4. (25 points)

  1. Design a microstripline using ________________

    2.  

  2. Write the S-parameters for a 3 inch long section of this microstripline.

 

 

ECE 540 Midterm II

 

Name _____________________________________

 

 

Problem 1 ______________ / 25 points

 

Problem 2 ______________ / 25 points

 

Problem 3 ______________ / 25 points

 

Problem 4 ______________ / 25 points

 

Total ______________ / 100 points