| MICROWAVE ENGINEERING |
| PAPER NO. 1 |
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| PUT ON: Dec,2K2 |
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EC-302 MICROWAVE ENGINEERING (B.Tech 6th & 7th Semester, 2122) Time : 3 Hours Maximum Marks : 60 NOTE:- This paper consist of Three Sections. Section A is compulsory. Do any Four questions from Section B and any two questions from Section C Section-A Marks : 20 1(a) What is frequency pulling in case of magnetrons? (b) List various methods of beam focusing in TWT's. (c) What is velocity Modulation? (d) Which microwave diode is suitable at low frequency and why? (e) What happens to the performance of PIN diodes above 100 MHz? (f) Ordinary low frequency circuit analysis is not adequate to describe the electrical phenomenon taking place at microwave frequencies, why? (g) List the properties of ferriets that make them useful in construction of Isolator and circulator's. (h) Why TEM waves cannot be propagated in waveguides? (i) Why rectangular waveguides are preffered over circular waveguides in some applications. (j) Why FET's are preffered over Bipolar Transistor at highest frequencies? Section-B Marks:5 Each 2. Discuss the problem of transit time effect in tubes at microwave frequencies. 3. What is Magic-Tee and why E-H plane is named as Magic-Tee. 4. Discuss the operation of a tunnel diode with its V-I characteristics. 5. Why stopping is needed in case of travelling wave magnitron? 6. Calculate ratio of cross-section of circular waveguide to that of a rectangular one if each is to have same cut-off wavelength for its dominant mode? Section-C Marks : 10 Each 7. Derive an expression for maximum possible theoretical efficiency of a two Cavity Klystron. 8. What are Ferrites? Discuss behaviour of ferrites in isolators and circulators. 9. Describe construction and operation of an PIN diode. Also discuss PIN diode as a switch. |