# Solved Problems-1

Problem-1
Determine the directivity of the following antennas:
1. Infinitesimal dipole or Hertzian dipole antenna
2. Half-wave dipole antenna
3. Quarter-wave monopole antenna
4. Hertzian monopole
Solution
(a) For an infinitesimal dipole antenna,

The radiation intensity is given as,

The power radiated by the antenna is,

The directive gain is given as,

The directivity is given as,

(b) For a half-wave dipole antenna,

The radiation intensity is given as,

The power radiated by the antenna is,

As obtained earlier, the integral is 1.2188. Hence,

The directive gain is given as,

The directivity is given as,

(c) For a quarter-wave monopole antenna,

The radiation intensity is given as,

The power radiated by the antenna is,

As obtained earlier, the integral is .

Hence,

The directive gain is given as,

The directivity is given as,

(d) For a Hertzian monopole antenna,

The radiation intensity is given as,

The power radiated by the antenna is,