Concepts of the Square Kilometre Array; toward the new generation radio telescopes

We present the concepts and their unique features presently being studied for the Square Kilometre Array expected to be operational between 2010 and 2015. A comparison is made between telescopes in operation to day and SKA´s ambitious set of requirements is presented. The framework for coordinating the studies of various countries aiming to conclude on a concept choice in 5 years is introduced. As a desirable side effect, efforts relevant for SKA, will result in new albeit smaller telescopes coming into operation at earlier stages.