Mention the factors on which the resultant pattern of array depends. UNIT II WIRE ANTENNAS AND ANTENNA ARRAYS 1. Write short notes on: (MAY / JUNE 2012) i). Solve the wave equation for uniform plane waves in an infinitely extending conducting medium. Explain the following terms with respect to antenna, (NOV. What are Hertzian dipoles? Derive the electric and magnetic field quantities of Infinitesimal dipole and radiation pattern. Explain the following terms with respect to antenna, (APRIL / MAY 2011) i). Derive the electric and magnetic field components of Hertzian dipole. Calculate the power density at distance of (i) 100m (ii) 1000m.
The total power delivered to the radiator is 100 KW. Calculate the effective length of a λ/2 antenna gives Rr=73 Ω effective aperture 0.13 m An antenna radiates power equally in all directions. An antenna has a loss resistance of 10 Ω power gain of 20 and directivity gain of 22. Determine the antenna efficiency and directivity.Ģ 21.
An antenna has a radiation resistance of 72Ω loss resistance of 8ƒ Ω power gain of 12dB. What is the gain of the antenna? Assume free space propagation. An antenna radiates a total power of 100W in the direction of maximum radiation, the field strength at a distance of 10Km was found to be 12mV/m. Calculate the gain of an antenna with a circular aperture of diameter 3m at a frequency of 5 GHz. Calculate the length of half wave dipole antenna meant to have wavelength at 60MHz. Find the field intensity at a distance of 100Km from the antenna. A radio station radiates a total power of 10KW and a gain of 30. Find the directivity of an antenna having radiation resistance of 72 Ω and loss resistance of 12 Ω and a gain of What is the maximum effective aperture of a microwave antenna which has a directivity of 900? 16. Show that an isotropic radiator radiating 1 KW power gives a field of 173mv/m at a distance of 1 Km. Write short notes on: (a) Fields of an oscillating dipole (b) Antenna field zones.
Derive an expression for field intensity at a distant point. Derive the relationship between radiation resistance and efficiency. Derive the relation between directivity and beam solid angle. Derive an expression for power radiated by an isotropic antenna. Define aperture of an antenna and find its relation with directivity. Draw the radiation pattern of: (i) Directional antenna. Write a note on radiation pattern and radiation lobes. With the help of neat diagrams explain the principle of radiation in antennas. Define the following parameters w.r.t antenna: i. 1 EC ANTENNA AND WAVE PROPAGATION FUNDAMENTALS PART-B QUESTION BANK UNIT 1 1.
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