Refractive index of materials at rf frequencies to make a smaller wire antenna

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I would like to ask a few questions. Does a table of refractive indices of materials at rf frequencies (say for TV) exists? Is there a way for me to estimate it for some materials? Are the refractive indices of these materials higher? Will those materials have low absorption losses at these frequencies? Would it be practical and sensible to make a TV antenna of smaller dimensions, and immerse this antenna in the medium? Could this idea work?
 
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I'm sorry for doing this but I would really like somebody to give an answer to this question. I'm not sure if increasing the refractive index of an antenna's surroundings permits me to tune into a frequency band with an antenna that has smaller dimensions. My thinking is that wavelength is what's important in tuning an antenna and not frequency. Please help.
 
Unless you fill the space between the antenna and the receiver with the medium, the waves will have to exit the medium and enter the air. If the speed of the waves in the medium is significantly different than the speed in air you'll have strong reflection at the interface and the coupling with air will be poor.
This is one problem I may think about.
I don't know where you can find data regarding speed of RF waves in media.
Maybe try a search on Google Scholar.
 
Thank you for your reply. I missed that point about reflection at the boundary between the media.

nasu said:
Unless you fill the space between the antenna and the receiver with the medium, the waves will have to exit the medium and enter the air.

Do you mean the space between the transmitting and receiving antenna or the space between the receiving antenna and the RF receiver? I'm assuming you mean the space between the antennas. I'm more concerned with reception than transmission. Reflection of RF waves at the boundary are a problem. If the antenna is smaller, then I could make a better antenna with more elements because the dime. As for total internal reflection, the reflection due to a traveling wave exceeding the critical angle only occurs from a medium of high refractive index to low refractive index. Some noise issues will occur from RF waves trying to escape the medium.

I'm suggesting this as a possible solution. The antenna should be small enough in size. The medium it is immersed in is larger and is shaped as a sphere. I am imagining that the reflections will occur close to the boundary of the sphere and will avoid interfering with the antenna. The medium selected has a high critical angle at RF frequencies if possible.

As for dispersion, I'm not sure how to deal with this in a simple, practical way. Calibrate the antenna to suit the medium? Add some electronic hardware that corrects for the aberration?

After seeing an article on Wikipedia on Snell's window, in which "Snell's window is a phenomenon by which an underwater viewer sees everything above the surface through a cone of light of width of about 96 degrees," maybe the shape of the medium's boundary and the antenna used is important somehow.