Electronics and Communication Engineering - Electromagnetic Field Theory

Exercise : Electromagnetic Field Theory - Section 2

A broadside array consisting of 200 cm wavelength with 10 half-wave dipole spacing 10 cm. And if each array element feeding with 1 amp. current and operating at same frequency then find the radiated power

730 W

73 W

100 W

None

Answer: Option

Explanation:

P_rad = n I² . R_r 10 x 73 x 1 730 watt.

For static magnetic field Maxwell's curl equation is given by

∇ .

= μ₀

∇ x

= 0

∇ x

= μ₀

∇ x

= μ₀/

Answer: Option

Explanation:

For static field, time varying factor will be zero, ∇ x H

If wave of critical frequency 30 MHz is departing at an angle of 60°, then the MUF is given to be

10 MHz

15 MHz

30 MHz

60 MHz

Answer: Option

Explanation:

MUF = f_c sec θ

An antenna having an effective temperature of 27°K is fed into a microwave amplifier that has an effective noise temperature of 30 K. Calculate the available noise power per unit bandwidth

30 K

57 K

27 K

3K, K is Boltzmann constant

Answer: Option

Explanation:

where K is Boltzmann constant.

10.

Two identical and parallel dipole antenna are kept apart by a distance of λ/4 in the H-plane. They are fed with equal currents but the right most antenna has a phase shift of + 90°. The radiation pattern is given as