In this paper we study the problem of explicitly constructing a dimension expander raised by [BISW04]: Let Fn be the n dimensional linear space over the field F. Find a small (ideally constant) set of linear transformations from Fn to itself {Ai}iI such that for every linear subspace V  Fn of dimension dim(V ) < n/2 we have dim iI Ai(V )  (1 + )