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EE163A Introductory Microwave Circuits
Fall, 2015
Prof. Y. Ethan Wang Electrical Engineering Dept.
UCLA
Lesson 1
Course info. Course organization TEM waveguides Non-TEM waveguides Equivalent Voltage & Currents
Textbook: David Pozar, Microwave Engineering, Ed. 4
EE163A Course Information Instructor: Y. Ethan Wang
7 Homeworks (30%), distributed on Wed. and due on next Wed.
1 Midterm (25%),
1 Final (45%), The finals week
No late submission of homework will be accepted !!!
No copy of homeworks and exams in any form!!!
Office hour: Tuesday, 3:30pm to 5:30pm
Office address: EN IV 56-147K
EE163A Syllabus 1. Review of transmission line& waveguides (4 hours)
2. Microwave network theory (Z/Y/S parameters, ABCD matrices) (4 hours)
3. Smith Chart and CAD design tools (4 hours)
4. Impedance matching and matching network (4 hours)
5. Microwave resonators, power splitters & couplers (6 hours)
6. Equivalent circuits of microwave devices (4 hours)
7. Noise and gain transfer in two-port networks (4 hours)
8. Amplifier gain, stability, VSWR requirements and design methods (4 hours)
9. Transistor amplifier design (6 hours)
Organization of EE163A
Network parameters & Smith Charts
Impedance Matching
Microwave Transistor Amplifier Design
Transmission line theory
Passive components
Active components
Microwave Network Theory
Microwave Passive Components
Microwave Filters
Designs of Microwave Circuits An example of Microwave Monolithic Integrated Circuits (MMIC)
Block Diagram of T/R Module
X-band T/R Module
64.5 x 13.5 x 4.5mm
Flow of Microwave Circuit Development
Waveguides Definition: Guiding structures for Electromagnetics Waves
Features: Infinitely long, transverse cross-sections are the same
Methodology of Analysis: -Assuming longitudinal variation of the field is known as exponential and solve for the transverse variation of the field for given B.C.
-Separate different field components and solve for one of them (longitudinal one) first
-Solve for other field components based on transverse-longitudinal relationship
Waveguide Solutions General waveguide field solutions are propagating in z direction can be written as:
transverse component longitudinal component
longitudinal variation
transverse variation
TEM waves:
TE waves:
TM waves:
Other hybrid waves
TEM Waveguides
TEM Waves (1) TEM waves is defined for the possibility of solution that satisfies:
One can either guess or prove from Maxwells equations that:
(Laplaces equations, classical electrostatic problems)
Conclusion: The field distribution of TEM waves imitate those (1) of electrostatic problems in the cross-section (2) of plane waves in the waveguide direction
The above assumption of the field direction determines that the wave has only z-propagating components
Wave Eq.:
Full solution:
Like in electrostatic problem, we can define potential function , so that
Voltage:
Current:
One can thus define wave Impedance:
TEM Waves (2)
Voltage & current can also be defined like the electrostatic case,
+
-
(conservative field)
(Laplaces equation)
From previously,
(Gausss law)
For TEM waves, this means:
The ratio between voltage & current is called characteristic impedance,
Parallel Plate Waveguides (1)
d
PEC
y
x
z
Dominant mode: TEM
d
W
Boundary conditions:
Assume no variation in x, thus,
Substitute the boundary conditions in the above,
The fields are,
Laplaces equation:
which gives,
The electric field is thus given by,
PMC
Parallel Plate Waveguides (2) Y-Z plane X-Y plane TEM
wave
The voltage is defined as,
The current is,
Then the characteristic impedance of the line is,
The phase velocity is also a constant,
d
PEC
y
x
z
d
W
PMC
(for TEM wave )
Microstrip Line
Compact, light weight Can be fabricated by photolithography Easily Integrated with other passive and active microwave
devices
Most popular type among planar transmission lines
Pros:
Cons: Low power capacity High loss
Microstrip Line
Define effective dielectric constant to represent the fringe field effect,
Approximately is given by:
Characteristic impedance
(why? ) Half air, half dielectric
Compact, light weight Can be fabricated by photolithography Easily Integrated with other passive and active microwave devices Low power capacity High loss
Coplanar Waveguides (CPW)
Empirical formulas can be used to find out the characteristic impedance and phase velocity
Support multiple quasi-TEM modes
Suited for Monolithic Microwave Integrated Circuit (MMIC) applications where vias and through holes to ground are difficult to make
An uni-planar transmission line
Coplanar Waveguide mode
Coplanar Slotline mode