I am aware of LED's that produce a full range of visible light, and also infrared. There are black-light ultraviolet LEDs, which are a fairly recent development, and which can be coated with fluorescent paint to produce white light. Is there such a thing as an LED that emits electromagnetic waves at microwave or radio frequencies? It seems like a device of this type would greatly simplify the manufacture of cellphones and radio controllers.

I think Gunn diodes can be used to generate microwaves when mounted in a wave guide. [en.wikipedia.org]. The don't work anything like LEDs though, they just oscillate at very high frequencies rather than emitting photons.

You used to get little radar modules for motion sensing that used them. I think there are better ways of doing it nowadays though.

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[www.hydraraptor.blogspot.com]

There's a HotWheels Radar gun in shops now for around $30 which uses a genuine microwave doppler radar at 10.525Ghz.

See [www.edparadis.com]

The reason that LEDs make generating light so easy is that light's wavelength is mere hundreds of nanometers, and it's easy to make electrons jump the proper distances.

However, microwaves and lower frequencies have wavelengths of centimeters, so more conventional methods are required. The above HotWheels radar uses a transistor of some kind in a resonant cavity, similar to a relaxation oscillator, driving a waveguide. I suppose that's about as close as you can get to a single component microwave source.

I've heard that terahertz radiation is starting to be used for things, and light is in the hundreds of terahertz range so the gap between methods is closing...

Gentleman:
The RF emitting diode exists by chance I have discovered such a circuit from which only a Diode emits RF waves(by chance ). I have sent letters to Science Magazine, RF & Microwaves ; there is no response.
regards,
ebby

Kapton, and other tape, all emit X-rays when peeled off the roll (in a vacuum). Believe it or not, it's enough to image through a finger bone.

Get a patent ASAP! If your discovery is valid, there could be a number of ways to capitalize on the phenomena you discovered. I'd be very interested to hear how it works out for you. good luck!
Bob

... this was statred in several science blogs and magazines, so not patentable - here a German source: [lindau.nature.com]

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]