Antenna and Wave Propagation Essay
MEENAKSHI SUNDARARAJAN ENGINEERING COLLEGE DEPARTMENT OF ECE EC2353-ANTENNAS AND WAVE PROPAGATION QUESTION BANK UNIT – I PART – A 1. What is retarded current? 2. Define hertzian dipole. 3. Define antenna gain. 4. What are the two types of radiation pattern? 5. State reciprocity principle. 6. Define antenna temperature. PART – B 1. Derive the expression for calculation of electromagnetic field due to an alternating current element. 2. Explain how the solutions to wave equations are arrived? 3. (i)Derive the relationship between directivity & effective aperture. ii)State and prove reciprocity principle with regard to antenna.
4. What are the various types of apertures? Find the effective aperture of a dipole antenna. 5. Explain the following (i)Vector effective length (ii)Antenna temperature 6. Write short notes on (i)Equivalence of radiation pattern (ii)Equivalence of impedances UNIT – II PART – A 1. Define antenna array. 2. Define broadside array. 3. Define end fire array. 4. Define the principle of pattern multiplication 5. Name & draw the different shapes of loop antenna? 6. What are the field components of loop antenna? PART – B .
Derive the expression for radiation resistance of half wave dipole? 2. Deduce an expression for the radiation pattern of a broadside array with two point sources. 3. Deduce an expression for the radiation pattern of an end fire array having two point sources. 4. Derive the expression for the normalized field pattern of uniform linear array. 5. What are the four types of amplitude distribution in arrays with non-uniform excitation and explain binomial array. 6. Explain the principle of pattern multiplication with two examples. UNIT – III PART – A 1. State Huygens principle 2.
What is the difference between slot antenna and its complementary dipole antenna? 3. What is the relationship between the terminal impedances of slot and dipole antennas? 4. What are the drawbacks of lens antenna? 5. What are the different types of horn antennas? 6. Estimate the diameter and the effective aperture of a paraboloidal reflector antenna required to produce a null beamwidth of 10° at 3GHz. PART – B 1. Explain the radiation from an elemental area of a plane wave. 2. Explain the methods of images for antennas above ground 3. Show the relationship between dipole and slot impedances . Explain the following: (1) Corner reflector and (2) Flat reflector 5. Explain non-metallic dielectric lens antenna with neat diagram 6. Explain E plane metal plate lens antenna with neat diagram. UNIT – IV PART – A 1. Name and draw a frequency independent antenna. 2. Why folded dipole antenna is used in yagi uda antenna? 3. State the principle of operation of a turnstile antenna. 4. What are the advantages of patch or micro strip antenna? 5. How spherical waves are generated? 6. Determine the gain of a cassegrain antenna of diameter 70 metre at a frequency of 8. 45 GHz.
Assume an aperture efficiency of 80%. PART -B 1. Explain the construction, operation and design consideration for a rhombic antenna 2. What is yagi – uda antenna? Explain the construction and operation of yagi uda antenna. Also explain its general characteristics. 3. What are the different modes of operation of helical antenna? Explain in detail. 4. Explain in detail about spiral antenna? 5. Explain the techniques used for gain measurements. 6. Derive the expression for radiated fields and characteristic impedance of the infinite biconical antenna. UNIT – V PART – A 1. Define maximum Usable Frequency. . Define skip distance. 3. What is meant by fading? And explain its types. 4. What is meant by Surface Wave? 5. Define critical frequency. 6. What is wave impedance? PART – B 1. Derive an expression for the refractive index of the ionosphere in terms of the electron number density and frequency. 2. Explain the ground wave propagation in detail. 3. Explain the electrical properties of Ionosphere. 4. Discuss the effects of earth’s magnetic field on ionosphere radio wave Propagation. 5. Explain the Tropospheric propagation in detail. 6. Explain the structure of ionosphere in detail.