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Real Poynting vector

Because of its importance this vector ExH is called the Poynting Vector and is normally

in the time domain denoted by N.

N = E xH . (7.14)

We notę that at this stage the Poynting vector has been defined of terms real vectors E and H; that those fields may be either steady or time varying, and the Poynting vector

is in generał a time-varying quantity. For steady or time varying fields, the vector N can

contain a steady component and a fluctuating component. In a sinusoidal steady State

situation there are two components, one at d.c. and one at twice the operating freguency.