Numerical Sheet6

NUMERICAL SHEET 6 RADIATION AND ANTENNAS 1. Find the radiation resistance of a Hertzian dipole of length λ/40, λ/60 and λ/80. (0.493Ω, 0.219Ω, 0.123Ω). 2. Find the directivity of an half wave antenna whose radiating power is 1W. (1.644) 3. An antenna whose radiation resistance is 300Ω operates at a frequency of 1 GHz and with a current of 3 A. Find the radiated power. (2700W) 4. What is the effective area of a half-wave dipole operating at 500 MHz?(Directivity:1.644). (0.047m^2) 5. Find the effective area of a Hertzian dipole operating at 100 MHz. (1.07m^2) 6. An EM wave of 1 GHz is radiated by an antenna to cover a distance of 100 km. Determine the (333µs) 7. The directivity of an antenna is 30 and it operates at a frequency of 100 MHz. Find its effective aperture area. (21.48m^2)