Addition of runs to a two-level supersaturated design

The purpose of this article is to introduce a new class of extended E(s2)-optimal two level supersaturated designs obtained by adding runs to an existing E(s2)-optimal two level supersaturated design. The extended design is a union of two optimal SSDs belonging to different classes. New lower bound to E(s2) has been obtained for the extended supersaturated designs. Some examples and a small catalogue of E(s2)-optimal SSDs are also included.