Thoose days the hitachi's u chip is the smallest known microchip on the market . There are controvercials for different reading ranges . The general opinion is that the tag's read range is within few centimeters .
Why so , and why you cannot increse its range . Is there some fundamental restrcition due to size of antenna and wavelength that does not allow bigger range to happen ?
I will be glad if you put some math in the explainations
Thank you