JNTU
JNTU B.Tech III ANTENNAS AND WAVE PROPAGATION Previous Question Paper (January/February - 2023 - R13)
Note: i) Question paper consists of Part A, Part B.
ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions.
iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Determine the radiated power of antenna which has radiation resistance of 300 ohms and current of 5A.
Answer
The radiated power Prad is calculated using the formula Prad = I2Rrad, where I is the RMS current and Rrad is the radiation resistance. Given I = 5 A and Rrad = 300 Ω, Prad = 52 × 300 = 25 × 300 = 7500 W or 7.5 kW.
What is antenna efficiency? How it is related with directivity.
Answer
Antenna efficiency (η) is the ratio of the power radiated by the antenna to the total power supplied to it. It accounts for losses in the antenna structure. It is related to directivity (D) and gain (G) by the expression G = ηD, where the efficiency η = Rrad / (Rrad + Rloss).
Write the Fermat’s Principle.
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Mention the design Considerations of Pyramidal Horns.
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What are the advantages and applications of microstrip antenna?
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Write short notes on zoning.
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Define point source.
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List the precautions to be taken for error free antenna measurements.
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Define skip distance.
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Write the effect of Earth’s Curvature on wave propagation.
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Part B
An antenna has a radiation resistance of 72 ohms, a loss resistance of 8 ohms and a power gain of 12 dB. Determine the antenna efficiency and directivity.
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Compare the far field components of small loop and short dipole.
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Elaborate the radiation mechanism of Quarter Wave Monopole and Half Wave Dipole antenna with current distribution characteristics.
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A pyramidal horn is having E-plane aE = 10λ. The horn is fed by a rectangular waveguide with TE10 mode. Let δ = 0.2λ in the E-plane and 0.375λ in the H plane. Find (a) Length L, (b) E-Plane and H-plane flare angles, (c) H-plane aperture, (d) Half power beam width and directivity.
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With neat diagram, elaborate the construction and working of Yagi-Uda antenna with its characteristics and what are the applications of it.
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Explain in detail the design aspects of microstrip antenna and also discuss why rectangular type is mostly used. What are the limitations of rectangular patch in microstrip antenna?
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With relevant diagram, explain the operations of Flar Sheet and Corner Reflectors with different corner angles.
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With a neat example, elaborate the principle of pattern multiplication.
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How to design binomial array antennas?
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Explain the atleast two antenna gain measurement methods with suitable block diagram.
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Elaborate on Sky wave propagation.
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What are the different effects of earth’s curvature?
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Write short notes in duct propagation.
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Explain the concepts of Multi-hop Propagation.
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