Coures: BEng (Hons) in Electrical and Electronic Engineering

1. EEEC6430310
Electromagnetic Fields and Waves
Faculty of Engineering and Computer Technology
Laboratory Manual
Lecturer: Ravandran Muttiah BEng (Hons) MSc MIET
Year/Semester: Year 2 / Semester 1
Academic Session: 2021/2022
The information in this documentis important and should be noted by all students undertaking the
Bachelor of Engineering (Honours) in Electrical and Electronic Engineering
Approved by Coordinator: Endorsed By Dean:
------------------------------------------ __________________

2. AIMST University Faculty of Engineering and Computer Technology
BEng (Hons) in Electrical and Electronic Engineering Electromagnetic Fields and Waves 1
50 + j100 Ω
Smith Chart Laboratory
(1) Plot the impedances given in table 1 on to the Smith chart.
Table 1
𝑍(Ω) 𝑧 Γ
𝑍1 = 100 + j50 𝑧1 = 2 + j Γ1 = 0.45∠27°
𝑍2 = 75 − j100 𝑧2 = 1.5 − j2 Γ2 = 0.65∠ − 38°
𝑍3 = j200 𝑧3 = j4 Γ3 = 1∠28°
𝑍4 = 150 𝑧4 = 3 Γ4 = 0.5∠0°
𝑍5 = ∞ 𝑧5 = ∞ Γ5 = 1∠0°
𝑍6 = 0 𝑧6 = 0 Γ6 = 1∠180°
𝑍7 = 50 𝑧7 = 1 Γ7 = 0
𝑍8 = 184 − j900 𝑧8 = 3.68 − j18 Γ8 = 0.97∠−6°
(2) A loss free transmission line of characteristic impedance 50 Ω is terminated with a
real impedance of 30 + j100 Ω. If the line is lengthened by 0.093𝜆. What is the
value of the new termination required to ensure that the impedance seen by the
generator is unchanged?
(3) Use Smith chart to find the input impedance 𝑍in looking at the input of a
transmission line as shown in figure 1 and 2.
Figure 1: Actual circuit.
𝑍L
𝑍in 𝑍0 = 50Ω
0.3𝜆

3. AIMST University Faculty of Engineering and Computer Technology
BEng (Hons) in Electrical and Electronic Engineering Electromagnetic Fields and Waves 2
1 + j2 Ω
Figure 2: Normalised circuit.
(4) A signal generator has an internal impedance of 50 Ω. It needs to feed equal power
through a lossless 50 Ω transmission line to two separate resistive loads of 64 Ω and
25 Ω at a frequency of 10 MHz. Quarter wave transformers are used to match the
loads to the 50 Ω line.
(a) Determine the required characteristic impedances and the physical lengths of
the quarter wavelength lines assuming the phase velocities of the waves
traveling on them is 0.5𝑐.
(b) Find the standing wave ratios on the matching line sections.
(5) To show how a transmission line terminated with an arbitrary load may be matched
at one frequency either with a series or parallel reactive component in each case
connected at a defined position, supposing a loss free air spaced transmission line of
characteristic impedance 50 Ω operating at a frequency of 800 MHz is terminated
with a circuit comprising a 17.5 Ω resistor in series with a 6.5 nH inductor. How
may the line be matched?
(6) A 50 Ω lossless transmission line is connected to load impedance, 𝑍L = 35 −
j47.5 Ω. Find the position 𝑑 and length 𝑙 of a short circuit stub required to match the
load at a frequency of 200 MHz. Assume that the transmission line is a coaxial line
filled with a dielectric material for which 𝜀r = 9.
(7) Show how an impedance of 10 + j10 Ω may be matched to 50 Ω with 2 different ‘L’
section matching networks at an operating frequency of 500 MHz.
𝑍L
1