Can a Tiny Antenna Transmit Long Wavelength EM Waves?

[nsaspook]

So this is the reason why visible light can't be emitted by antenna?
no exception?

View attachment 246298How about chest x-ray machine. How do they direct the x-ray? nuclear decay since antenna not possible?

Visible light can be received by fairly conventional antennas at the nano-scale so if we can't emit visible light from an antenna it's not because of a physics limitation on EM antenna dipole radiation at that wavelength.
https://www.me.gatech.edu/featured_colarectenna

 

[DaveE]

NO, it's dangerous

And expensive.

 

[sophiecentaur]

A little matching will do the trick

And a massive amount of copper in the ground mat, of course. That would count as the antenna, I suppose.
The VLF transmitting station at Rugby is another example of a notionally 'small' antenna in terms of wavelength. It has a long history of different installations, from as low frequency as 16kHz. One of the arrays transmitted on 60kHz (5km wavelength) and the antenna consisted of a number of 260m masts. That MSF signal did go a long way! The actual size of the array would be open to interpretation but it certainly was hard work going lower than a quarter wave.
But these small arrays did actually work and provide(d) usable services.

 

[Herman Trivilino]

My nephew was asking me last week whether if Antman was the size of Ant. He could still send radio waves in his radio or cell phone.

Ha ha! He's ready to learn about scaling.

http://www.lr-web.dk/Lru/microsites...ojekt_5.9_Scaling_the_Physics_of_Lilliput.pdf