Biju Patnaik University of Technology 2008-7th Sem B.Tech (B Tech),ester antenna engineering . - Question Paper
BPUT(B Tech),7th semester antenna engineering ques. paper.
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Total number of printed pages -4 B, Tech P EEC 5401Seventh Semester Examination - 2008 ANTENNA ENGINEERING Fulf Marks - 70
Time-3 Hours
Answer Question No. 1 which is compuisory and any five from the rest.
The figures in the right-hancf margin indicate marks.
1. Justify ; 2x10
(a) Isotropic radiator radiates equally in all directions.
(b) Standing waves are present along hal f wave dipole.
(c) If ihe feed point of the antenna is a! a current maximum, the input Impedance js only real.
Sdbst' tuw method 01 arsonna mr! ii twra<K (ft bntJfl imsthod
(<*} Anipote/a"ioncant&a3rfyot<anod by pwer timmp&rwi
(fj CaHegtttn fc*d mochanism 11 very papula/ for to* nooe apC*C*fcOfw
(gj The(?ff<*flcvolaoofniO*KK)homr3mor than rhal ol corvontonal !hom
(h) IHom to a ftarsd out wavogmdto
(i) Tho (toarodptfafuatiOncAn t oMamftd by dilferont shapes of the microstnp antenna
(j) The method otmomorl is useful fo* finding field tiistnbuTfon in slois and other wire antomas
2, (a) Explain, tho following; 6 (i). Method of exeiiation ol anjoas (If) impedance matching tachhiques, PEEC 5401 2 Contd
(to) An array of dipoles of ~ lengthm encMire
mode i$ to txoOuce a power gam ot 24. Find (j) aay ieogth, number & elements
wMwi spacer | and (u) Null to INufli beam
WVtTl 4
3 What is a tog-penodic antenna ? What are rhe wiient features of sucft antenna ? Draw a 'tog? pufKxfcc array and wrne the equabons involve in CJesjQAing the same. 10
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a (a) Enumerate the sabenl features of resonant aniennss How these are different Irom travelling wave antenna ? 5
(b) A rhombic antenna is to operate at a frequency of 45 MH;t with the elevation angle 35* with respect lo ground. Find (I) Height of the rhombic, (ii) tilt angle, and
(iii) length of each wire. 5
5. Explain the following in relation with a patch antenna, 2,5x4
(a) Patch parameters
(b) Methods of bandwidth control
(c) Shapes of antenna
(d) Characteristic impedance.
6. (a) Explain the radiation phenomena of a
waveguide slot. 4
(b) The aperture dimensions of a pyramidal horn are 10 x 5 cm. It is operating at 6.6 GHz. Find fi) beam width, (ii) power gain and (iti) directivity. 6
7. (a) Why antenna measurements are
necessary ? What are the drawbacks in measurements of antenna parameters? 4
(b) Explain impedance measurement by Wheatstone bridge method. 6
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