re: "It's the concept that is patented - ring oscillator. It shouldn't matter if someone else implements our concept with differnet materials or makes it a different size - it would still be a ring oscillator and an infringement."

As most have probably realized the above statement is a two edged sword. The other edge, given that my statement above is valid, is that if a patented concept was implemented earlier by someone else using older bigger parts the recert may be faced with a prior art issue.