Gives direction and rate of energy flow of an electromagnetic wave.
S=E×H gives power flow per unit area (W/m²). For a plane wave S=E²/(2η) with η=377 Ω in free space. Poynting's theorem balances stored energy, dissipation and flow. Explains energy transfer in cables.
A 100 V/m peak field carries about 13 W/m².
The Poynting vector tells you how energy moves through a field, which is needed for power transfer and antenna design.
Gives direction and rate of energy flow of an electromagnetic wave.
The Poynting vector tells you how energy moves through a field, which is needed for power transfer and antenna design.
The power per unit area carried by an electromagnetic field, with direction along the energy flow.
It shows that energy flows in the space around the conductors rather than inside them, which explains how power moves along the cable.
Typical applications include calculating the power flow in a coaxial cable between source and load, estimating the energy flux reaching a receiving antenna and checking energy flow near a high-power microwave horn.
Study "Maxwell's equations" first (topic 93 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
Direction of propagation. Time-average S. Radiation intensity.
A 100 V/m peak field carries about 13 W/m².
The next topic is "Transmission line theory", which builds directly on this one.
It is classed as Advanced in Electrical Engineering (topic 94 of 106). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Electrical Engineering.
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