High performance RF front-end receiver suitable for telemeter solution for smartgrid is proposed in this article. It is based on a tunable polyphase filter topology to perform high image rejection. The design allows frequency control making it suitable for multi-standards applications. In order to improve the maximal achievable image rejection ratio (IRR), both formal analysis and statistical method leading to the filter optimal sizing have been dealt with. The effects of parasitic capacitances and components mismatch are also considered and discussed. Steps within CMOS polyphase filter design flow are then provided to guarantee high image rejection performance. The proposed tunable polyphase filter has been used within a low-IF double-quadrature RF front-end receiver. More than 60dB IRR and good linearity in high frequency applications are ensured.