Question

What are the fundamental limits of very tiny radios?

Answer 1

For a hard SF story, I'm wondering about the physical limits of communications devices in a micro robot, say, the size of a mosquito. Figure one microgram mass.  Real rechnology has already come a long way since stories on this subject such as Hogan's Bug Park.  Assuming no limits on technology, but still made of atoms and employing the known laws of physics, what are some fundamental limits of making machines this small be able to communicate?  This includes limited availability of  mass (1 or 2 µg) length/area (2.5mm body length; appendages could fold out to form an antenna) power (chemical power from sugar and ambient oxygen) It appears that a short range link with a special (large, powerful) docking station is not a problem. But what about longer range communications between such micro machines?  I recall a new article where a FM radio was built using a single nanotube. So I assume that receiving a sufficiently strong signal requires only a few atoms. But transmitting, and receiving the signal strength a peer can transmit, will have some hard limits that will find this scale challenging

Answer 2

$<marquee><b>Radio is the technology of using radio wavesto carry information, such as sound, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.[n 1] When radio waves strike an electrical conductor, the oscillating fields induce an alternating currentin the conductor. The information in the waves can be extracted and transformed back into its original form.$