1. Antennas & Wave Propagation
Unit 1

2. Radiation resistance of a current element
The radiation resistance of a current element can be found out by using the power radiated from a current element. The total power radiated by a current element can be obtained by the radial poynting vector over a spherical surface.
Consider a spherical shell with the current element I dl placed at the centre of the spherical coordinate system as shown in the figure below. The point P at which power radiated is to be calculated is independent of an azimuthal angle Φ, so the element of area ds on the spherical cell is considered as strip.
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9. Power radiated from a half-wave dipole antenna
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24. Average Power interms of effective or RMS current
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