1. Microwave Engineering Instructor: Athar Hanif
Lecture-3
Microwave Engineering
Instructor: Athar Hanif

2. Quiz-1 Time Allowed: 30 minutes Total Marks: 20
Q.1:A plane wave traveling in z- direction in a dielectric medium with єr =2.55 has an electric field given by Ey = E0 cos(ωt-βz). The frequency is 2.4 GHz, and E0 = 30 V/m.
Find the amplitude and direction of the magnetic field (2 Marks)
Find the phase velocity and wavelength.
(3 Marks)
Find the phase shift between the positions Z1 = 0.5 m and Z2 = 1.7 m. (5 Marks)

3. Quiz-1 Time Allowed: 30 minutes Total Marks: 20
Q.2: A RFC is constructed by winding four turns of AWG 38 copper wire(σcu =64.516х106S/m) on a 2 mm ceramic core diameter(μr = 1) of 0.1 mm length. Estimate
The inductance (3 Marks)
Stray capacitance (2 Marks)
Resistance (2 Marks)
Resonance frequency (3 Marks)

4. Microstrip Transmission Line
Most popular type of planer transmission line
Geometry of microstrip line

5. Microstrip Transmission Line
Dielectric were not present(єr =1)
Simple TEM waves
Dielectric were present(єr ≠1)
Does not support TEM waves

6. Microstrip Transmission Line
In practical application, h<<λ
Fields are quasi-TEM
Єe is the effective dielectric constant
1< єe< єr

7. Microstrip Design Step-1: find W/h ratio єr and Z0 = known
Step-2: For W/h ≤ 2

8. Microstrip Design
For W/h ≥ 2
Step-3: Effective dielectric constant

9. Microstrip Design
Step-4: Find Z0
For W/h ≤ 1
For W/h ≥ 1

10. Microstrip Design Step-5: (1) Attenuation due to dielectric loss
Where tanδ is the loss tangent of the dielectric

11. Microstrip Design Attenuation due to conductor loss
Rs is the surface resistivity of the conductor

12. Microstrip Design

13. Microstrip Design

14. Design Problems
Problem-1: calculate the width and the length of a microstrip line for a 50Ω characteristic impedance and a 900 phase shift at 2.5 GHz. The substrate thickness is h = 0.127cm, with єr = 2.20
Problem-2: Design a microstrip transmission line for a 100Ω characteristic impedance. The substrate thickness is 0.158cm, with єr = What is the guide wavelength on this transmission line if the frequency is 4.0 GHz.

15. Assignment
Problem: A 100Ω microstrip line is printed on a substrate of thickness cm, with a dielectric constant of 2.2. Ignoring losses and fringing fields, find the shortest length of this line that appears at its input as a capacitor of 2.5 pF at 2.5 GHz. Repeat for an inductance of 5 nH.

16. Stripline Most popular type of planer transmission line
Geometry of microstrip line

17. Stripline
Phase velocity and the propagation constant of the stripline is given by

18. Stripline

19. Stripline Design
Step-1: Find√ єr Z0
Step-2: Find the strip width

20. Stripline Design
Step-3: Dielectric attenuation

21. Stripline Design
Attenuation due to conductor loss

22. Stripline Design Where ‘t’ is the thickness of the strip
Rs is the surface resistivity of the conductor and given by

23. Stripline Design Step-4: Total attenuation constant is given by
Step-5: The wavelength on the stripline is
Attenuation in term of wavelength

24. Design Problems
Problem-1: Find the width for a 50Ω copper stripline conductor, with b = 0.32cm and єr = If the dielectric loss tangent is and the operating frequency is 10 GHz, calculate the attenuation in dB/λ. Assume a conductor thickness of t = 0.01mm.
Problem-2: Design a stripline transmission line for a 70Ω characteristic impedance. The ground plane separation is cm, and the dielectric constant of the filling material is What is the guide wavelength on this transmission line if the frequency is 3.0 GHz.

25. Assignment (due on )
Problem: A microwave antenna feed network operating at 5 GHz a 50 Ω printed transmission line that is 16λ long. Possible choices are (1) copper microstrip, with d = 0.16 cm, єr = 2.20, and tanδ = 0.001, or (2) copper stripline, with b = 0.32 cm, єr = 2.20, and tanδ = Which line should be used, if attenuation is to be minimized?

26. Project-1(due on )
Design a microstrip line (characteristic impedance = 50 Ω, phase shift = 900,substrate FR-4 thickness = 31mil, 61mil, dielectric constant = 4.47, and tangent loss = 0.019)
Hand calculations
Verify your design using SERENADE
HARDWARE implementation
Results (hardware )

27. Instructions Each group has two students. Do your own work.
Write project report.
No late submission.

28. Instructions The format for design report should be as follows
1. Title page (including your name, the course number and the date)
Your signature after the statement
I certify that this design is the result of my own efforts.
(Signature) Date:
2. Design objectives and specifications
3. Design steps (including all, mentioned in problem statement)
4. Design modifications, if any
5. Computer design verifications
6. Results (hardware)
7. Conclusions