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2018-Dec ECD-313 205

This document outlines the examination details for the B. Tech Dual-Degree in Electronics & Communication Engineering, specifically for the Antenna and Wave Propagation course. It includes various questions related to antenna theory, including derivations, calculations, and design aspects of different types of antennas. The exam covers topics such as Hertzian dipole antennas, directive gain, array factors, Yagi-Uda antennas, and radio wave propagation.

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Riya Singhal
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22 views1 page

2018-Dec ECD-313 205

This document outlines the examination details for the B. Tech Dual-Degree in Electronics & Communication Engineering, specifically for the Antenna and Wave Propagation course. It includes various questions related to antenna theory, including derivations, calculations, and design aspects of different types of antennas. The exam covers topics such as Hertzian dipole antennas, directive gain, array factors, Yagi-Uda antennas, and radio wave propagation.

Uploaded by

Riya Singhal
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Roll No •

National- Institute of Teclinorogy, Ifamirpur


Name of the Examination: B. Tech Dual-Degree (End Semester Examination)

: Electronics & Communication 5th


Branch Semester
Engineering.
Course Name : Antenna and Wave Propagation Course Code : ECD-313

Time: 3 Flours Maximum Marks: 60


Note: I. All questions are compulsory.
2. Assume necessary data if necessary.

Q.1.(a). Derive the field equation for a hertizian dipole antenna starting from Maxwell equation. Derive the
expression for its radiation resistance. (6)
OR
Q.I.(b). Derive the expression for the field quantities radiate from X./2 dipole and prove that the radiation resistance
to be 73ohm. (6)

• Q. I.(c). An electric field strength of E = 10µV/m is to be the measured at the observation point 0=7r/2, 500Km from
a half wave dipole antenna operating at f= 50 MHz (6)
(i) What is the length of dipole.
(ii) Current at must be fed into the antenna
(iii) Average power radiated
(iv) If the transmission line charactertic impedence is 75 ohm is connected to the antenna determine the
standing wave ratio.

Q.2.(a). Find the directive gain for (i) hertizian dipole antenna (ii) half wave dipole antenna. (6)

Q.2.(b). (i) Derive the expression for radio link (Friis formula). (3)

(ii) Two antennas are 50 km apart in radio communication, transmitting antenna delivers 2000W. It's antenna
gain is 40 in the direction of receving antenna and the power absorbed by receiving antenna is 20µW. Calculate
(a) Electric field at receving antenna (b) Effective aperature of receving antenna. (3)

Q.3.(a). Derive the expression for the array factor of a linear array of N isotropic element spaced k/2 apart fed with
signals of equal amplitude and phase. obtain the directions of maxima and minima and the direction of nulls.(6)

Q.3.(b). What is the significance of binomial array? Design a three element array if nulls comes at 0°. (6)

Q.4.(a). Discuss the construction and design of a Yagi-Uda antenna and explain its principle of operation and also
design a 3 element Yagi-Uda Antenna for 900MHz. (6)

Q.4.(b). Explain the operation and design of a helical antenna and a 16 turn helical beam antenna has circumfernce
and turn spacing 7/4, calculate (6)
(i) HPBW (ii) FNBW
(iii) Axial Ratio (iv) directivity.

Q.5.(a). Describe the structure of the atmosphere and specify the factors affecting the radio wave propagation. (6)

Q.5.(b). Discuss briefly on the types of fading and Obtain an expression for the refractive index of an ionospheric
layer. (6)

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