College of technical sciences/Bani Walid Exam Final Date 25 July 2024
Microwave Engineering Electric electronic Eng. Dept.
̂-direction is propagating in the Ẑ -direction
Q1- Assume a plane wave with electric field oriented in the X
ohms−1
through dry soil at 1 MHz at this frequency typical material properties are ε = 3ε0 and σ = 10−5 ( ) where
m
1 j j
(ε ≡ (ε̃) − σe ) = (3ε0 −
ω 2π106
10−5 ) = (3 − 2π106 ε 10−5 ) ε0 = (3 − j0.179)ε0 = ε′ −
0
jε′′ Find β(ω), α(ω), phase velocity vp and amplitude decrease within 1 Km distance.
Q2- A copper stripline transmission line is to be designed for a 100 Ωcharacteristic impedance The
ground plane separation is 1.02 mm and the dielectric constant is 2.20, with tan δ = 0.001. At 5 GHz,
find the guide wavelength on the line and the total attenuation.
Q3- A circular copper waveguide has a radius of 0.4 cm and is filled with a dielectric material having
𝜀𝑟 = 1.5 and tan δ = 0.0002. Identify the first four propagating modes and their cutoff frequencies. For
the dominant mode, calculate the total attenuation at 20 GHz.
Q4-A four-port network has the scattering matrix shown as follows. (a) Is this network lossless? (b) Is
this network reciprocal? (c) What is the return loss at port 1 when all other ports are terminated with
matched loads? (d) What is the insertion loss and phase delay between ports 2 and 4 when all other
ports are terminated with matched loads? (e) What is the reflection coefficient seen at port 1 if a short
circuit is placed at the terminal plane of port 3 and all other ports are terminated with matched loads?
Good luck Mr. Yahya
