1. Electromagnetic waves and Applications Part III:
Microwave Fundamentals
Yungui MA (马云贵)
Office: Room 209, East Building 5, Zijin’gang campus

2. Electromagnetic spectrum
Millimeter waves
300 MHz
3 GHz
30 GHz
300 GHz
3 THz
30 THz
300 THz
Photonic devices
Electronic devices
Microwaves
THz gap
visible
Radio waves UV
Infrared
Microwave bands
Band P L S C X Ku K Ka
Freq (GHz)
0.23-1
1-2
2-4
4-8
8-12.5

3. Microwave applications
Wireless communications (cell phones, WLAN,…)
Global positioning system (GPS)
Computer engineering (bus systems, CPU, …)
Microwave antennas (radar, communication, remote sensing, …)
Other applications (microwave heating, power transfer, imaging, biological effect and safety)

4. 课件下载

5. Syllabus Chapter 1: Transmission line theory
Chapter 2: Transmission lines and waveguides
Chapter 3: Microwave network analysis
Chapter 4: Microwave resonators
Reference books：
David M. Pozar, Microwave Engineering, third edition (Wiley, 2005)
Robert E. Collin, Foundations for microwave engineering, second edition (Wiley, 2007)
J. A. Kong，Electromagnetic theory (EMW, 2000)

6. Chapter 1: Transmission line theory
1.1 Why from lumped to distributed theory?
1.2 Examples of transmission lines
1.3 Distributed network for a transmission line
1.4 Field analysis of transmission lines
1.5 The terminated lossless transmission line
1.6 Sourced and loaded transmission lines
1.传输线理论一（前言介绍，波动方程推导，场分析，单端口传输线分析，接源与负载传输线分析）。

7. 1.1 Why from lumped to distributed theory?

8. 1.1 Why from lumped to distributed theory?
At low frequencies:
Can simply use a wire to connect two components
f =50 HZ, wavelength = 6 x 106m;
At high frequencies:
Cannot simply use a wire to connect two components
f =500 MHZ, wavelength = 0.6 m;

9. 1.1 Why from lumped to distributed theory?
H field
E field
Microwave component: electric size << the operating wavelength

10. Transmission line theory
R = series resistance per unit length, for both conductors, in /m;
L = series inductance per unit length, for both conductors, in H/m;
G = parallel conductance per unit length, in S/m;
C = parallel capacitance per unit length, in F/m.
Loss: R (due to the finite conductivity) + G (due to the dielectric loss)

11. Transmission line theory
Bridges the gap between field analysis and basic circuit theory
Extension from lumped to distributed theory
A specialization of Maxwell’s equations
Significant importance in microwave network analysis
The key difference between circuit theory and transmission line theory is electrical size. Circuit analysis assumes that the physical dimensions of a network are much smaller than the electrical wavelength, while transmission lines may be a considerable fraction of a wavelength, or many wavelengths, in size. Thus a transmission line is a distributed-parameter network, where voltages and currents can vary in magnitude and phase over its length.

12. 1.2 Examples of transmission lines
(2) Coaxial line
(1)Two-wire line
Magnetic field
(dashed lines)
Electric field
(solid lines)
(3) Microstrip line

13. Review: Kerchhoff’s law
1.3 Distributed network for a transmission line
Review: Kerchhoff’s law
KCL:
KVL:

14. 1.3 Distributed network for a transmission line

15. 1.3 Distributed network for a transmission line

16. Derivation of differential transmission line equation
KVL:

17. Derivation of differential transmission line equation
KCL:

18. Derivation of differential transmission line equation

19. Phasor form of sinusoid haromic wave
Time factor convention

20. Derivation of differential transmission line equation

21. ki, Phase constant, rad/m
kr, attenuation constant, nep/m

22. Impedance, wavelength and phase velocity
TL current:
Characteristic impedance:
Voltage in the time domain:
Wavelength:
Phase velocity:

23. Propagation constant:
Characteristic impedance:
Wavelength:
(what happens if exchange L and C ?)
Phase velocity: