This discussion focuses on calculating the diameter of a stepped four-coil array necessary for achieving a rotational electromagnetic (EM) field at the speed of light for a specified frequency. The calculation example provided indicates that for a 2-meter diameter coil array, a frequency of approximately 47.71 MHz is required to achieve this effect. The conversation clarifies that while the EM field can propagate at the speed of light, it does not imply that any physical object or field rotates at that speed. The distinction between phase velocity and actual rotational speed is emphasized throughout the discussion.
PREREQUISITESEngineers, physicists, and researchers involved in electromagnetic field applications, coil design, and those interested in the theoretical aspects of wave propagation and phase velocity.
The sides of the coils would share the same physical space, they would be inductively coupled, yet would have quadrature currents.Fluxation said:For example in the case of a cubical array made of square coils.
Just to mention the radiation mechanism from this structure. Irrespective of any rotating fields, radiation occurs due to the acceleration of the electrons in the wire. As the electrons are accelerated in the circular path of the wire, radiation is maximum in the plane of the coils. In this direction there is only plane polarisation, being the simple addition of the radiation fields from each coil. If the coils are spaced by a significant part of a wavelength and driven with a phase difference then we will see a directional pattern but still in the plane of the coils and plane polarised.Baluncore said:The sides of the coils would share the same physical space, they would be inductively coupled, yet would have quadrature currents.