The use of Planar Circularly Symmetric (PCS) Electromagnetic Band-Gap (EBG) structures for optimizing the performances of single antenna elements and arrays is been discussed. The key advantage of using this sort of super structures is that they are planar and thus very cheap to manufacture with respect to alternative EBG structures based on vertical pins. In this contribution a review of the design principles and of the antennas based on PCS EBG which have been developed at TNO will be presented. Also a review of the applications that effectively used the benefit associated with them will be discussed. In conclusions, while EBG technology has been promising marvels for phased array applications for quite some time, its PCS implementation e...