Gujarat Technological University 2011 B.Tech Electronics and Communications Engineering Antenna & Wave Propagation - Question Paper
Seat No.: _____ Enrolment No.______
GUJARAT TECHNOLOGICAL UNIVERSITY
B E Sem-VI exam May 2011
Subject code: 161003
Subject Name: Antenna & Wave Propagation Date:19/05/2011 Time: 10.30 am – 01.00 pm
Total Marks: 70
Instructions:
1. Attempt all ques.. 2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Attempt all subsequent short ques.. (i)What is Antenna? (ii) describe Radiation Resistance. (iii) Show Antenna Field Zones.(iv) describe Directivity. (v) What is Beam Solid Angle? (vi) describe HPBW. (vii) How many square degree equals to solid angle of a sphere?
(b) Attempt Any 2 of the subsequent. (i) Show that effective length of receiving antenna is identical as that of transmitting antenna. (ii) Show that directivity of a current element is 1.5 or 1.76 db. (iii) Starting with field equations of short dipole, show that amplitude of radiation field and induction field are equal at ?/6 distance. (iv)Derive expression for Effective Aperture A
of an antenna having impedance Z
A
and terminating impedance Z
T.
e
Q.2 (a) discuss Principle of trend Multiplication for array of point sources. Also provide 2 examples of short dipoles.
(b) discuss Broadside and End-fire Array, considering linear array of 4 isotropic sources.
OR (b) discuss Schelkunoff Theorem and show its usefulness. 07
Q.3 (a) Compare far fields of Short Dipole and Small Loop antenna. 07 (b) Derive expression for Radiation Resistance of Loop antenna. 07 OR
Q.3 (a) Show that Short Magnetic dipole is equivalent to a loop. 07 (b) discuss Practical design considerations for the Monofilar Axial Mode Helical
antenna. 07
Q.4 (a) discuss Yagi-Uda antenna in detail. 07 (b) discuss Frequency Scanning Arrays and mention its advantages. 07
OR Q.4 (a) Attempt details of Any 2 of the subsequent.
(i) Lens Antenna. (ii) Micro Strip Antenna (iii) Slot Antenna. (iv) Log Periodic Antenna.
(b) Show how impedance matching is done with the help of Folded Dipole Antenna.
Q.5 (a) discuss Antenna Gain measurement methods. 07 (b) discuss Characteristics of Ionosphere layer and describe subsequent terms
MUF, Critical Frequency & Skip Distance. 07
OR
Q.5 (a) discuss various modes of Propagation with its practical significance. 07 (b) define Antennas for Terrestrial Mobile communication systems. 07
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one
07
07
07
07
07
07
Seat No. Enrolment No.
GUJARAT TECHNOLOGICAL UNIVERSITY
B E Sem-VI Examination May 2011
Subject code: 161003
Subject Name: Antenna & Wave Propagation
Time: 10.30 am - 01.00 pm Total Marks: 70
Date:19/05/2011
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Attempt all following short questions.
07
07
(i)What is Antenna? (ii) Define Radiation Resistance.
(iii) Show Antenna Field Zones.(iv) Define Directivity.
(v) What is Beam Solid Angle? (vi) Define HPBW.
(vii) How many square degree equals to solid angle of a sphere?
(b) Attempt Any Two of the following.
(i) Show that effective length of receiving antenna is same as that of transmitting antenna.
(ii) Show that directivity of a current element is 1.5 or 1.76 db.
(iii) Starting with field equations of short dipole, show that amplitude of radiation field and induction field are equal at X/6 distance.
(iv)Derive expression for Effective Aperture Ae of an antenna having impedance ZA and terminating impedance ZT.
(a) Explain Principle of Pattern Multiplication for array of point sources. Also give two examples of short dipoles.
Q.2
07
(b) Explain Broadside and End-fire Array, considering linear array of four isotropic sources.
07
OR
(b) Explain Schelkunoff Theorem and show its usefulness.
07
07
07
07
07
(a) Compare far fields of Short Dipole and Small Loop antenna.
Q.3
Q.3
Q4
Q4
(b) Derive expression for Radiation Resistance of Loop antenna.
OR
(a) Show that Short Magnetic dipole is equivalent to a loop.
(b) Explain Practical design considerations for the Monofilar Axial Mode Helical antenna.
(a) Explain Yagi-Uda antenna in detail. 07
(b) Explain Frequency Scanning Arrays and mention its advantages. 07
OR
(a) Attempt details of Any Two of the following. 07
(i) Lens Antenna. (ii) Micro Strip Antenna (iii) Slot Antenna. (iv) Log Periodic Antenna.
(b) Show how impedance matching is done with the help of Folded Dipole 07 Antenna.
Q.5
07
07
07
07
(a) Explain Antenna Gain measurement methods.
(b) Explain Characteristics of Ionosphere layer and define following terms MUF, Critical Frequency & Skip Distance.
OR
(a) Explain different modes of Propagation with its practical significance.
(b) Describe Antennas for Terrestrial Mobile communication systems.
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1
Q.5
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Attachment: |
| Earning: Approval pending. |
