The mechanism behind radiation including explanation of the term radiation resistance. This video deals with a single current segment or area, not an array of elements or current maximums.
The radiated field varies directly with current integrated over a length of space, and the cosign of the angle from the antenna direction.
This video demonstrates that a long length of conductor wound up, bent up, or packed into a given linear space has no different radiation coupling than a single straight conductor occupying the same spatial distance so long as current distribution is the same.
What matters for radiation is not how much wire we pack into a length of space, but rather how we distribute the integrated or effective current over that spatial distance.
This video is not to endorse or discourage any particular design. Designs are a necessary mix of multiple compromises.
Part of transferring energy is power factor correction. Reactive power, or the volt-amperes reactive, also leads to losses or coupling problems. Radiation resistance and current distribution is just one part of a complex problem.
This video makes three important points I'd like everyone to take away:
1.) Antennas radiate all of the power applied, less the power lost as heat, regardless of size
2.) Radiation resistance in a simple small antenna is all about the current distribution and spatial length of the radiator in fractions of the wavelength
3.) People call antenna things they are not either by mistake or as an effort to "fluff up" something that is not really special
I hope to find time to go through various antennas and explain how they actually work and what they really are.
31 июл 2024