The variance in refractive indeces is what makes color corrected lenses possible.
Wwhere di you get a figure for the refractive index at 90 mHz ? Refractive inceces are given for things that are to pass light, evren UV or IR, but llight.
No material is going to act the same at 900 mHz as at Angstroms and shit. Ain't happenin.
Are you trying to make some kind of focusable UHF transmitter or someting ? That might be illegal. If so, count me in.
As you were informed in your last thread, the velocity factor in water is V = 1/sqrt(Er) where V is the relative velocity (velocity factor) and Er is the effective relative permeability (dielectric constant), which for salt water is about 81. This results in a V of 1/9. The wavelength now becomes 33.3/9cm. That is, about 3.7cm.
The resonance of a sphere of salt water is something I can't help you with.
From good old electromagnetism and optics, the refractive index of water depends on its molecular properties, and as light is a form of electromagnetic radiation, its velocity is affected when it enters water. So, wavelength of light changes in water but is frequency remains unaltered, so light slows down in water. As salt water is an ionic fluid(as compared to sweet water) the effect is more. The question with regard making salt water resonate is not clear. Specifically, what would you expect to see if the water goes into resonance ? As an analogy, please consider what happens in a microwave oven - microwaves(electromagnetic radiation) excite the water molecules in food, which in turn return to their ground state(quantum mechanics) by releasing energy absorbed from the microwaves to the surrounding food molecules -- food is cooked. So if you aim to heat the salt water, the mechanism already exists. Hope that helps.
The extent of the losses dependent on the concentration of the brine.
There would be a bit as the impedance mismatch at the surface would tend to reflect a standing wave back across the interior, but I think you would be wiser to make the sphere effective lambda/2 across. There will certainly be some geometry fudge factors for the object being of the same order as the wavelength and spherical. It is not for nothing that undergraduates do the maths for particle in a square box first.
The OP might find it useful to read Agilents presentation on dielectric spectroscopy so that he has some idea about how the dielectric constant of water with and without salt actually varies with frequency.
Spherical cavity resonators exist, they were used in the microwave feed for the LEP collider at CERN (LHCs precursor). So there should be data for them somewhere.
The refractive index will depend on frequency, of course.
Salt water is conductive, so there's a LOT of damping, and it's unlikely you can use any resonance that may occur. Computing the resonance is a boundary-value problem in differential equations, so you need to know if the boundary is metal, or air (like, a salt-water balloon, you can ignore the small thickness of latex rubber). Then, you pull out a book on wave physics...
_Methods of Theoretical Physics_, Morse & Feshbach (especially chapter 11)
and look at the roots of spherical Bessel functions (that's where resonances occur)
1.0, 1.4303, 1.8346, 2, 2.2243... are the roots that apply to a metal sphere enclosure with a small hole to inject power (a Helmholtz sphere). That corresponds to resonances at wave-length-in-medium of
lambda = pi * R, pi * R/1.4303, pi * R/1.8346...
Now,comes the tricky part. Some of those resonances mightn't couple at all to an RF input, depending on things like polarization.
The refractive index will depend on frequency, of course.
Salt water is conductive, so there's a LOT of damping, and it's unlikely you can use any resonance that may occur. Computing the resonance is a boundary-value problem in differential equations, so you need to know if the boundary is metal, or air (like, a salt-water balloon, you can ignore the small thickness of latex rubber). Then, you pull out a book on wave physics...
_Methods of Theoretical Physics_, Morse & Feshbach (especially chapter 11)
and look at the roots of spherical Bessel functions (that's where resonances occur)
1.0, 1.4303, 1.8346, 2, 2.2243... are the roots of j_n(pi*x) that apply to a metal sphere enclosure with a small hole to inject power (a Helmholtz sphere). That corresponds to resonances at wave-length-in-medium of
lambda = 2 * R, 2 * R/1.4303, 2 * R/1.8346...
Now,comes the tricky part. Some of those resonances mightn't couple at all to an RF input, depending on things like polarization.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.