Question 1

Consider a loss less antenna with a directive gain of + 6 dB. If 1 mW of power is fed to it the total power radiated by the antenna will be

Accepted Answer

6 dB = 10 log10 ⟹ = 100.6 ⟹ 3.98 Pr = 3.98 mW.

Question 2

Find the radiation resistance of an antenna of length λ/10 meter?

Accepted Answer

.

Question 3

A transmission line is feeding 1 watt of power to a horn antenna having a gain of 10 dB. The antenna is matched to the transmission line. The total power radiated by the horn antenna into the free space is

Accepted Answer

= 101 ⟹ Pr = 10 watt.

Question 4

The radiation resistance of a λ/16 wire dipole in free space will be nearly

Accepted Answer

Rr = 80p2.

Question 5

In a conductor which of the following relations hold good?

Accepted Answer

Inside a conductor free charge is zero, hence, ∇ x D = 0.

Question 6

A rectangular waveguide measures 3 x 4.5 cm internally and has a 10 GHz signal propagated in it. Calculate the wave impedance for dominant mode.

Accepted Answer

Wave impedance .

Question 7

A uniform plane wave is one in which

Accepted Answer

For uniform plane wave, E and H must be in a plane but perpendicular to each other.

Question 8

The function f(x - vot) represent which of the following?

Accepted Answer

f(x - vot) represents in +ve direction while f(x + vot) represents a progressive wave in -ve direction.

Electromagnetic Field Theory Questions