Microwave Engineering Introduction Lecture 1

Microwave related knowledge.

1. Microwave Engineering

2. Grading Policy 12.5 % Quizzes 12.5 % Assignments 25% Mid Exam 50% Final Exam

3. Text/Reference Book Microwave Engineering 4th Edition by David M. Pozar. Foundations for Microwave Engineering , Robert E. Collins , 2 nd Edition.

4. Course Learning Outcomes (CLO’s) COURSE LEARNING OUTCOMES: Upon successful completion of the course, the student will be able to: S. No. CLO Domain Taxonomy level PLO 1. Explain the performance of a microwave device by looking at its s-parameters Cognitive 2 1 2. Analyze active and passive microwave devices from given specifications Cognitive 4 2 3. Explain basic communication link design, signal power budget, noise evaluation and link carrier to noise ratio Cognitive 2 1 4. Design and implement microwave filters for given specification Cognitive 6 3

5. Lecture Distribution Lecture Topics CLO Covered 1 Introduction . Introduction to Electromagnetics Microwave Frequency bands, General Applications of Microwaves, Advantages and disadvantages of Microwaves CLO-1 2 Transmission line equation in time and frequency(phasor) domain, lossless transmission line, Dispersion less TL.   CLO-1 3 TL input impedance, time average power, return and insertion losses, VSWR CLO-1 4 Generator and load mismatches on TLs, smith chart CLO-1 5 Transmission line matching using lumped L Networks, Quarter Wave transformer matching CLO-1 6 Concept of Mode, Characteristics of TEM, TE and TM Modes for waveguides. Rectangular Waveguide CLO-1

6. Lecture Distribution Lecture Topics CLO Covered 7 Impedance and Admittance matrices, CLO-1 8 S parameters and scattering matrix   CLO-1 9 Transmission (ABCD) Matrix CLO-1 10 signal flow graphs CLO-1 11 Basic properties of dividers and couplers CLO-2 12 T junction and resistive power dividers CLO-2

7. Lecture Distribution Lecture Topics CLO Covered 13 Wilkinson power divider CLO-2 14 Quadrature and rat race hybrid coupler   CLO-2 15 Coupled and Lange directional couplers CLO-2 MID EXAM 17 Klystron, Travelling wave tube and magnetron CLO-2 18 Role of mixer and pre selector filter in heterodyne receiver CLO-2

8. Lecture Distribution Lecture Topics CLO Covered 19 Active microwave circuits: Two port power gains CLO-2 20   Amplifier Stability CLO-2 21 Single stage Amplifier: Design for maximum gain CLO-2 22 Single stage Amplifier: Design for specific Gain CLO-2 23 Microwave Filter design by insertion loss method CLO-4 24 Scaling of low pass prototype filters, stepped impedance low pass filter   CLO-4

9. Lecture Distribution Lecture Topics CLO Covered 25 Stub synthesis, Kuroda’s identities, Stub low pass filters CLO-4 26 High pass and band pass filters CLO-4 27 Microwave Propagation (Propagation modes, Multipath propagation, Atmospheric attenuation, polarization ) CLO-3 28 Link budget calculations (Transmission power, received power, EIRP, Noise power, Free space loss) CLO-3 29 Vector Network Analyzer FINAL TERM

10. Introduction to Microwaves

11. ELECTROMAGNETIC SPECTRUM

12. Radio waves and Microwaves Microwaves  are  electromagnetic waves with   frequencies  between 300MHz (0.3GHz) and 300GHz in the electromagnetic spectrum Radio waves are electromagnetic waves within the frequencies 30KHz - 300GHz, and include microwaves.  Microwaves are at the higher frequency end of the radio wave band and low frequency radio waves are at the lower frequency end.

13. Radio Spectrum

14. Microwave Frequency Bands The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older use includes lower frequencies. Most common applications are within the 1 to 40 GHz range

15. Advantages of Microwaves Large Bandwidth : The Bandwidth of Microwaves is larger than the common low frequency radio waves. Thus more information can be transmitted using Microwaves. It is very good advantage, because of this, Microwaves are used for Point to Point Communications. Better Directivity : At Microwave Frequencies, there are better directive properties. This is due to the relation that As Frequency Increases, Wavelength decreases and as Wavelength decreases Directivity Increases and Beam width decreases. So it is easier to design and fabricate high gain antenna in Microwaves. .

16. Contd…… Small Size Antenna : Microwaves allows to decrease the size of antenna. The antenna size can be smaller as the size of antenna is inversely proportional to the transmitted frequency. Thus in Microwaves, we have waves of much higher frequencies and hence the higher the frequency, the smaller the size of antenna. Low Power Consumption : The power required to transmit a high frequency signal is lesser than the power required in transmission of low frequency signals. As Microwaves have high frequency thus requires very less  power. Effect Of Fading :  The effect of fading is minimized by using Line Of Sight propagation technique at Microwave Frequencies. While at low frequency signals, the layers around the earth causes fading of the signal

17. Applications of Microwaves   Following are the other main application areas of Microwaves: Communication : Microwave is used in broadcasting and telecommunication transmissions. As described earlier, they have shorter wavelengths and allows to use smaller antennas. The cellular networks like GSM, also uses Microwave frequencies of range 1.8 to 1.9 GHz for communication. Microwaves are also used for transmitting and receiving a signal from earth to satellite and from satellite to earth. Military or Army also makes use of Microwaves in their communication system. They uses X or ku band for their communication. Remote Sensing : The most common application of Microwave is its use in RADAR (Radio Detection and Ranging) and SONAR (Sound Navigation and Ranging). RADAR is used to illuminate an object by using a transmitter and receiver to detect its position and velocity. .

18. Contd….. Heating :  We uses Microwave Oven to bake and cook food. It is very convenient electronic machine which performs the heating task very cleanly and in a very less time. Medical Science : Microwave's heating properties are also used in Medical Science. Microwave also have Medical Applications such as it is used in diagnosis and various therapies.

19. Disadvantages of Microwaves Line-of-sight will be disrupted if any obstacle, such as new buildings, are in the way Signal absorption by the atmosphere. Microwaves suffer from attenuation due to atmospheric conditions. Towers are expensive to build.

20. Any Question…?

21. Have A Nice Day…