1. ELEC 401 MICROWAVE ELECTRONICS
Instructor: M. İrşadi Aksun
Phone:
Textbooks:
“Microwave Engineering” by D. M. Pozar, 2nd Edition, John Wiley & sons, Inc
“Modern Microwave Circuits” by N. Kinayman and M. I. Aksun, Artech House 2004.

2. to make students familiar with high-frequency concepts:
The aim of the course is
to make students familiar with high-frequency concepts:
wave nature of the voltages and currents;
analysis and design of high-frequency circuits;
understanding of the effects of high-frequency signals in circuits and in materials.

3. What do we mean by high-frequency?
We mean frequencies at which the wavelength is comparable to or less than the physical sizes of the interested components

4. What is Wavelength?
WAVELENGTH is a distance a single frequency wave propagates during its complete cycle (=period T)

5. Outline
Chapter 1: Motivation & Introduction
Chapter 2: Review of EM Wave Theory
Chapter 3: Plane Electromagnetic Waves
Chapter 4: Transmission Lines (TL)
Chapter 5: Microwave Network Characterization
Chapter 6: Smith Chart & Impedance Matching
Chapter 7: Passive Microwave Components

6. Chapter 1 Motivation & Introduction
What do we mean by “Microwave” signals and circuits?
Electrical signals within 300 MHz and 300 GHz range are referred to as microwave signals, and
circuits operating in this frequency range are called microwave circuits.
1 MHz
1 GHz
1 Mega Hertz = 1 x 106 Hz
1 Giga Hertz = 1 x 109 Hz

8. Motivation & Introduction
Why do we need to work in “Microwave” frequencies?
Because systems designed in Microwave frequencies have some unique features:
More bandwidth
Line-of-sight communications
More antenna gain

9. Motivation & Introduction
Why do we need new tools for the analysis of high-frequency circuits?
What is wrong with the traditional AC circuit theory?
To partially understand the answers to these questions, let us study a simple one-component circuit operating at a high frequency !!!

10. Motivation & Introduction
Example: Find the current I2 at the output terminal of a series resistor when the current at its input port is known.
I2=I1, is this correct ?

11. Motivation & Introduction
I2=I1 is an approximation valid for low-frequency operations;
Current is the propagation of electron disturbances;
Physical disturbances take finite amount of time to travel from input to output.
Time delay for a disturbance to travel to output

12. Motivation & Introduction
Assume l=1 cm, and v=c=3.0x108 m/sec (speed of light)
for f= 300 KHz,
for f=300 MHz
for f=3 GHz

13. Motivation & Introduction
A high-frequency capacitor and its frequency characteristics

14. Motivation & Introduction
High-frequency resistors and their typical frequency characteristics

15. Motivation & Introduction
A typical amplifier circuit: circuit diagram

16. Motivation & Introduction
and realization

17. Motivation & Introduction Reflection and Transmission (Refraction)

18. Motivation & Introduction
Although we have plenty of experience on reflection and transmission of light, like reflections on mirrors, mirages and rainbow, we have very little information how these phenomena occur.

19. Motivation & Introduction
Microwaves, Antennas and Optics Problems are governed by the following Maxwell’s Equations:
Microwaves engineering can be defined as applied electromagnetic fields engineering.