Question

If the power radiated by a quarter-wave monopole is 100mW then power radiated by a half wave dipole under same current input is _____

(a) 100W

(b) 100mW

(c) 200W

(d) 200mW

This question was posed to me in quiz.

My query is from Power Radiation from Half Wave Dipole in chapter Antenna Parameters – II of Antennas

Answer 1

The correct option is (d) 200mW

The explanation: Average Power radiated from the half-wave dipole \(P_{avg-hlf}=I_{rms}^2 R_{hlf}\)

⇨ \(\frac{P_{avg-hlf}}{P_{avg\, mono}} = \frac{R_{hlf}}{R_{mono}} = \frac{73}{36.5}=2\) (under same current)

⇨ Pavg-hlf = 2Pavg mono = 2*100mW=200mW