Simple electromagnetic wave including delay

  • #1
a1titude
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$E(r,t)$ and $H(r,t)$ around $I*\sin(2*pi*f*t)$
I want to derive the electric and magnetic field at a point around an infinitely long wire which carries a sinusoidal alternating current. And I want the answer includes the phase delay according to the limited speed of propagation of the wave. Surely the answer must satisfy the Maxwell's equations. I have never seen such answers from anywhere yet. Please, someone derive them for me or recommend me some references.
 
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  • #2
Look at the sections 8.2-8.3 on retarded potentials in Stratton, Electromagnetic Theory.
 
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  • #3
a1titude said:
And I want the answer includes the phase delay according to the limited speed of propagation of the wave.
That is a type of travelling wave antenna, but with an infinite length wire.

The velocity of the sinusoid propagating along the wire is critical in determining the field pattern.
For sub-luminal conductor propagation, (with insulation or oxide), most of the energy is launched in the direction the sinusoid is propagating along the conductor, the conductor forward of there, can often be discounted.

The problem was solved over 100 years ago. You have obviously been reading the wrong books and papers.

This paper, by Beverage, Rice and Kellogg, is well worth reading at breakfast.
https://www.crosscountrywireless.net/The Wave Antenna.pdf
 
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FAQ: Simple electromagnetic wave including delay

What is a simple electromagnetic wave?

A simple electromagnetic wave is a wave consisting of oscillating electric and magnetic fields that propagate through space. These fields are perpendicular to each other and to the direction of wave propagation, forming a transverse wave.

How is the delay in an electromagnetic wave defined?

The delay in an electromagnetic wave refers to the time it takes for the wave to travel from one point to another. This delay can be influenced by the medium through which the wave is traveling and the distance between the points.

What factors affect the delay of an electromagnetic wave?

The delay of an electromagnetic wave is affected by the distance it travels, the medium it passes through (such as air, vacuum, or other materials), and the wave's frequency. Different materials have different refractive indices, which can slow down the wave and increase the delay.

How can you calculate the delay of an electromagnetic wave?

The delay of an electromagnetic wave can be calculated using the formula \( \text{Delay} = \frac{\text{Distance}}{\text{Speed of the Wave}} \). In a vacuum, the speed of the wave is the speed of light, approximately \( 3 \times 10^8 \) meters per second. In other media, the speed is reduced by the medium's refractive index.

Why is understanding the delay in electromagnetic waves important?

Understanding the delay in electromagnetic waves is crucial for various applications, including telecommunications, radar, and GPS systems. Accurate knowledge of wave delay ensures proper synchronization and functioning of these technologies, leading to reliable communication and navigation.

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