None of the IPL teams were able to qualify for the semis ?? What were the reasons behind such a low show ?

I was quite a bit surprised to see none of the IPL teams proceedin to the semis of the Champions League ... or is this because T20 is such an unusual format that you cannot underestimate any opposition ( like Zimbabwe beating Aussies at the inaugural T20 championship ) ... or was that a case of IPL teams performing poorly again ...