Osmania University (OU) 2006-2nd Sem B.E Electronics & Tele-Communication Engineering 3/4 (E.C.E)(ESTER)SUPPLEMENTARY ,emr, Antennas and propagation - Question Paper
B.E 3/4 (E.C.E)(II-SEMESTER)SUPPLEMENTARY EXAMINATION,December,2006
Antennas and propagation
M V S R Engg. College. Cods No. 11329
HYDERABAD
B.E. 3/4 (ECE.) II Semester (Supplementary) Examination, December 2006
Subject: Antennas and Propagation
Time: 3 Hours) {Max. Marks : 75
Note: Answer All questions of Part - A and Answer any five questions
from Part-B. IIBMAMT
PART-A (25 Marks) M VS R Engg. College
HYDERABAp
1. What is the directivity of half wave dipole and If it Is 90 % efficient, calculate gain. (2)
2. What Is the first side lobe level of a uniform linear array and sketch the radiation pattern ? (2)
3. An antenna receives 2 m w of power when the incident wave has an associated electric field of 20 mv/m rms. Find the aperture
area. (3)
4. Define antenna efficiency. Given RL = 36.5 Q find efficiency of quarter wave monopole. (2)
5. What Is the radio horizon distance for standard atmosphere in kilometers ? (2)
6. Deline vertical height of Ionospheric layer and $kip distance of tonosph&rlc layer. (3)
7. What is the impedance of reflector in Yagi - uda antenna.
Compare with director elements. (3)
8. Find the null-to-nuli beam width of 2m paraboloid reflector used at
5 GHz. (2)
9. Draw a typical non-radiating slot in the rectangular wave guide.
Why It Is non-radiating slot? (3)
10. How do you increase the radiation resistance by folding the dipole ?
What Is radiation resistance of folded dipole? (3)
PART-A (50 Marks)
11.(a) Define filed strength and power patterns of antenna. (4) (b) Derive an expression for the radiated power of half-wave dipole. (6)
12. (a) Explain the salient features of uniform linear arrays. (6)
(b) Find out the basic transmission loss between a ground based on antenna and air bone antenna when the distance between the antennas are 16 and 160 km at ff * 0.3 GHz. (4)
13.(a) Draw a typical log-periodic antenna and explain its design methodology. (5)
(b) Design a log-periodic antenna to obtain a gain of 9 dB to operate over a frequency range of 125 MHz - 500 MHz (Assume T * 0.861 0*0.162). (5)
14,(a) Explain the salient features of horn antenna . (2)
(b) State Babinets principle and explain. (5)
(c) A parabolic reflector with a mouth diameter of 22 m operates at f 5 GHz. If has an illumination efficiency of 0.6 . Find the power gain. (3)
15.(a) Bring out the differences between indoor and outdoor ranges. (4)
(b) Describe a method of measurement of antenna impedance. (6)
16.(a) What is a Troposphere. Derive the expression for the field strength
at a point due to space wave. (6)
(b) A communication system is to be established at a frequency of 60 MHz with a transmftter of 1.0 kw. The field strength of the directive antenna is 3 times that of a half-wave antenna. Ht 50 m, hr = 5m,. A field strength of 80 v/m is required to give satisfactory reception. Find the range of the system. (4)
17. Write short notes on the following: (3+3+4)
VSBEngg.
(b) Ground Wave Propagation HYDERABAD
(c) Binomial array
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