dr. yungui ma ( 马云贵 ) e-mail: [email protected]@zju.edu.cn office: room 209, east...
TRANSCRIPT
Dr. Yungui MA ( 马云贵 )E-mail: [email protected]
Office: Room 209, East Building 5, Zijin’gang campus
Microwave Microwave FundamentalsFundamentals
Electromagnetic spectrum
Band P L S C X Ku K Ka
Freq (GHz)
0.23-1 1-2 2-4 4-8 8-12.5 12.5-18 18-26.5 26.5-40
300 MHz 3 GHz 30 GHz 300 GHz 3 THz 30 THz 300 THz
Photonic devices
Electronic devices
Microwaves THz gap visibleRadio waves UV
Microwave bands
Millimeter waves
Infrared
Microwave applicationsWireless 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)
http://mypage.zju.edu.cn/mayungui/640892.html
SyllabusChapter 1: Transmission line theory
Chapter 2: Transmission lines and waveguides
Chapter 3: Microwave network analysis
Chapter 4: Microwave resonators
Reference books : 1.David M. Pozar, Microwave Engineering, third edition (Wiley, 2005)2.Robert E. Collin, Foundations for microwave engineering, second edition (Wiley, 2007) 3.J. A. Kong , Electromagnetic theory (EMW, 2000)
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
1.7 Introduction of the Smith chart
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 infinite conductivity) + G (due to the dielectric loss)
Transmission line theory
Transmission line theory
Bridges the gap between field analysis and basic circuit theory
Extension from lumped to distributed theoryA specialization of Maxwell’s equationsSignificant 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.
1.1 Why from lumped to distributed theory?
1.1 Why from lumped to distributed theory?
1.2 Examples of transmission lines
(2) Coaxial line
Magnetic field
(dashed lines)
Electric field
(solid lines)
(3) Microstrip line
(1)Two-wire line
Review: Kerchhoff’s law
1.3 Distributed network for a transmission line
KCL: 01
n
kki KVL: 0
1
n
kkv
1.3 Distributed network for a transmission line
1.3 Distributed network for a transmission line
1.3 Distributed network for a transmission line
(Telegrapher equations)
1.3 Distributed network for a transmission line
Impedance, wavelength and phase velocity
Wavelength:
Phase velocity:
1.3 Distributed network for a transmission line
)cos()cos(),( 00 zktVzktVtzv ii
Voltage in the time domain:
ik/2
fk
vi
p
Characteristic impedance:
TL current:
Characteristic impedance:
Phase velocity:
Wavelength: (what happens if exchange L and C ?)
1.3 Distributed network for a transmission line
LC /2
LCvp /1
Propagation constant: