  The concentration of electromagnetic waves (EM) is of utmost importance in
many engineering applications such as solar-cells. According to the
transformation optics (TO) methodology, a feasible approach for obtaining
arbitrary shape concentrators is proposed. In contrary to the previous works,
the obtained materials are homogeneous and independent of the concentrator
shape. That is regardless of the input geometry always one constant material,
which is optic-null medium (ONM), is used and the performance of device will
not alter. This competency will ease the design process and circumvent the
sophisticated calculations of the necessitating materials. To authenticate the
concept, several numerical full-wave simulations were performed for different
shape concentrators. It was observed that numerical results exhibit strong
agreement with the theoretical investigations and corroborate the generality
and effectiveness of the proposed designing method.
