Assume I put an RF antenna in front of an object (typically the face of someone sitting in a chair, so able to move about +/- 10cm in all directions) at a typical distance of 1m. If I consider the system antenna/face as a resonant cavity, I'd get a fundamental resonant frequency of about 150MHz.
I have a general physics education but no experience at all with RF antennas and resonators, so I have no orders of magnitude in mind. I realize such a 'resonant' cavity would be extremely poor, but how poor? My question is: is it conceivable to have enough resonance with basic antenna and processing electronics to be able to measure the mean distance to the face with a precision of say 1cm (i.e. measure the mean resonance frequency with about 1.5MHz precision), or is it an obvious and complete no go?
If it were conceivable, how 'clean' would the background need to be? Assuming there could be many unconstrained background objects (typically at a distance twice larger) all in a small room, could I just pick up the main resonance frequency around 150MHz for my measurement or would all the reflections / interferences with the other objects + room walls mess the signals completely up?
Note: I'm not expecting a detailed solution to my problem (although I'll happily take it if it comes :) I'm more looking for an "expert's feeling" like "yes, people have done that for decades", "maybe, you'd have to try" or "No way dude, you're completely dreaming".
In any case, if anyone sees any other (as cheap as possible, and most importantly automated and non intrusive) way to get such a measurement (+/- 1cm at 1m distance) please let me know.