SPPU Electronics and Telecom Engineering (Semester 6)
Antenna and Wave Propagation
May 2017
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Solve any one question from Q.1(a,b,c) &Q.2(a,b,c)
1(a) A uniform plane wave of frequency 5MHz has a average poynting vector 1.5W/m2. If the medium is lossless with relative permeability μr = 2 and relative permittivity \( \varepsilon r=3. \)/ Determine velocity of propagation, wavelength, intrinsic impedance of a medium and r.m.s. value of electric field.
8 M
1(b) Explain the following characteristic of wireless channel
i) Coherence band width.
ii) Coherence time and
iii) Fading.
6 M
1(c) Deriv vector potential A for an magnetic current source J.
6 M

2(a) What is polarization of wave? Explain linear and circular polarization of wave.
6 M
2(b) Write short note on
i) Virtual height.
Multihope Propagation.
6 M
2(c) The power radiated by a lossless antenna is 10 watts. The radiation intensity of this antenna is \( U=Bo\cos ^{3}\theta \left ( W/Sr \right )0\leq \pi /2 \ \ 0\ \ \leq \Phi \leq 2\pi .\)/ Find.
i) The maximum power density in (W/m2) at a distance of 1000 meter (assume for field distance) specify the angle where this occurs. ii) Directivity
iii) Gain of the antenna.
8 M

Solve any one question from Q.3(a,b) &Q.4(a,b)
3(a) Derive the equation for input impedance and directivity of half wave dipole.
8 M
3(b) Show the current distribution on small dipole and derive the equation for its input impedance.
8 M

4(a) Find the radiation efficiency of a single turn and eight-turn small circular loop at f = 100MHz. The radius of the loop is λ/25, the radius of the wire is 10-4λ and the turns are spaced 4×10-4λ apart. Assume the wire is copper with a conductivity of 5.7 × 107 (S/m) and antenna is radiating into free sace. (Where ohmic resistance per unit length/ohmic skin effect resistance per unit length = 0.38)
10 M
4(b) Give the comparison of far fields of small loop and short dipole.
6 M

Solve any one question from Q.5(a,b) &Q.6(a,b)
5(a) For two element array consisting identical radiators carrying equal currents in phase, obtain positions of maxima and minima of the radiation pattern if the distance of seperation d = λ
8 M
5(b) Derive antenna array factor for N-element linear array taking the centre element as reference for N is odd and even.
8 M

6(a) Draw and explain the radiation pattern of an endfire array.
8 M
6(b) Explain in brief Dolph - Tchbyscheff distribution. What is the need for Tchbyscheff distribution?
8 M

Solve any one question from Q.7 & Q.8(a,b)
7 Explain the following antennas with its structural details dimensions, radiation pattern, diagram, specifications, features and applications.
i) Micro strip antenna
ii) Lens antenna.
iv) Biconical antenna
18 M

8(a) Explain the working of Rhombic antenna in detail.
8 M
8(b) With the help of suitable diagram explain the operating principle of
i) Super turnstile
ii) Slot antenna.
10 M

More question papers from Antenna and Wave Propagation