new form of radio? EM-vortex transmissions - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: September 22, 2024, 07:34:46 am
content: I saw thishttps://www.popularmechanics.com/science/a62263447/first-electromagnetic-vortex-cannon/https://pubs.aip.org/aip/apr/article-abstract/11/3/031411/3306444/Observation-of-resilient-propagation-and-free?redirectedFrom=fulltextthough, I am having alot of time understanding it, because they use pressure as a word.. ? It looks like it has a interesting looking antenna plot.The key is that their horn is coaxial..? the transmission TE mode of a coaxial cable kinda has a doughnut vibe to itI often wondered about this, to build a coaxial "open" flare. I built some cones that can fit inside of each other a few years ago but I never setup the experiment because I don't understand the value. I just wanted to know if it could emit. If I take apart one of my incorrect antennas I can throw something that looks kind of similar together. I figured the radiation pattern would be some how bizzare.I wonder what my 15x10 inch cone would do if I put a 12x4 inch cone in the middle and hooked it up to some coax, should only take a minute to take one of my antennas apart, the cones exist. The narrow one was a fat dipole experiment. I even spot welded a end cap on the little cone during my spot welder experiments, metal forming is the hard part to make a dome..https://www.semanticscholar.org/paper/Analysis-of-a-coaxial-horn-antenna-using-FDTD-Barros-Silva/e6664e51571a10b6b8df59e78aececba0c1dbb32looks kinda like something with fluid dynamics.-coaxial cable TE modeThe benefit of the coaxial horn antenna seems to be wide bandwidth, much like how cable is very wide band (i.e. DC to 100GHz for the right size one). UWB pulses are currently used for distance finding (tags). I suppose naturally using the coaxial horn antenna for a wide band pulse leads to something interesting if you focus it right. i.e. "chirps" .I am not sure how this could revolutionize communication because its wide band, akahatedin any multi user system lol (its like a microwave spark gap transmitter, socially)

author: RoV
author_rank: Regular Contributor
timestamp: September 22, 2024, 05:29:01 pm
content: This remembers me of OAM (Orbital Angular Momentum) that I think was studied originally (for radio waves) by Tamburini and Thidé. See e.g.https://en.wikipedia.org/wiki/Orbital_angular_momentum_of_lightI believe radio applications didn't have success, because the waves propagate like doughnuts that become rapidly very large and can be detected only by a huge receiving antenna that can capture the full diameter (no field on the center). So the technique could only be proved at very small distances. I think it has optical applications, instead.

author: coppercone2
author_rank: Super Contributor
timestamp: September 22, 2024, 06:22:04 pm
content: This is what I thought about the coaxial antenna (I did not know about their design) that it would be useless for long distance, because its easy enough to build if you lose the fancy curveMost of what I see about UWB pulses is all about asset tracker stuff, aka I don't care. The smart tags all use UWB pulses (octave+) IIRC. Like 2-12GHzI want to see what their antenna does at a reasonable distance like 500metersThere is a interesting world of metalized foam coaxial structures that can be fabricated I think. Like if you put epoxy on a foam cut out and metalize it with tape, paint or chemicals, but I never figured outwhyI am kind of excited that someone did actually do SOMETHING with a coaxial horn antenna. blunderbuss antennaThey have a much slimmer taper then some of the round horns I have (20-26GHz) lens horn have a close to 75 degree angle, but those are waveguide fed...