Department of Electrical Engineering
Sessional II
Antenna & Radiowave Propagation
Program: BET
Semester: VII
Instructor: Syed Muzahir Abbas/Dr. Slialiid A. Khan
Date: 23/04/2009
Time Allowed: 60minutes
Total Marks: 90
Question#l: Choose the correct answer. (15)
1. The standard reference antenna for the directive gain is:
a) Infinitesimal dipole
b) Elementary doublet
c) Half wave dipole
d) None of the above
2. The antenna used as standard reference for directive gain is:
a) Quarter wave dipole b) Isotropic antenna
c) Elementary doublet d) Half wave dipole
3. The input impedance of a dipole antenna having tip-to-tip physical length equal to half
wavelength is:
a) Pure resistance
b) Pure capacitance
c) Inductive impedance d) Capacitance impedance
4. The input impedance of a short dipole with length nearer to 0.23 λ contains a reactance, which is
normally:
a) Large and capacitive b) Small and capacitive
c) Large and inductive d) Small and inductive
5. The near zone fields of an oscillating time varying dipole are:
a) Dynamic
b) Static
c) Quasi-static
d) None of the above
6. For half wave dipole the directivity D (in dB’s) is obtained to be:
a) 1.76
b) 2.15
c) 3 .14
d) 1.64
7. The directivity of a half wave dipole is given by:
a) 1.51
b) 1.64
c) 2.03
d) 2.54
8. Tire directivity of the small loop and short dipole has the following ratio:
a) 1:2
b) 2:1
c) 1:1
d) 1:4
9. To qualify as a small loop or short dipole their dimensions should be:
a)  /10
b)  /8
c)  /4
d)  /2
10. If a dipole has been cut from a metal sheet, leaving a slot, the dipole and slot are said to be
complementary. The terminal impedance of dipole 𝑍𝑑 , and that of slot 𝑍𝑠 , are related to the intrinsic
impedance of space 𝑍𝑜 by 𝑍𝑠 =:
a) 𝑍𝑑2 ⁄4𝑍0
b) 4𝑍02 ⁄𝑍𝑑
c) 𝑍02 ⁄4𝑍𝑑
d) 4 𝑍𝑑2 ⁄𝑍0
11. Patch is a:
a) High gain wide band antenna
b) High gain narrow band antenna
c) Low gain narrow band antenna
d) Low gain wide band antenna
12. The field patterns for the following antennas are identical provided E and H fields are
interchanged:
a) Dipole and Patch antenna
b) Dipole and Horn antenna
c) Dipole and Loop antenna
d) Dipole and Yagi antenna
13. A helical antennas is used for satellite tracking because of its:
a) Circular polarization
b) Linear polarization
c) Broad bandwidth
d) Good front to back ratio
14. The following terms spell the same meaning in reference to an antenna:
a) Near field and Principal zone
b) Near field and Fresnel zone
c) Near field and Fraunhofer zone
d) Far field and Fresnel zone
15. Two /2 dipoles are crossed at 90°. If the two dipoles are fed with equal currents, what is the
polarization of the radiation perpendicular to the plane of the dipoles if the currents are (i) in phase,
(ii) phase quadrature (90° difference in phase)
a) (i) LP & (ii) EP
b) (i) EP & (ii) LP
c) (i) LP & (ii) CP
d) (i) CP & (ii) LP
Answers for question1
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11
P12
P13
P14
P15
D
B
A
B
A
B
B
C
A
C
C
C
A
B
C