The primary task in any cognitive radio (CR) network is to dynamically sense the radio spectrum so as to reliably determine portion(s) of the frequency band that may be used for communication link(s). Recently spectrum sensing for CRs based on filter banks have been addressed in literature. It was suggested that using filter banks for spectrum sensing would offer new opportunities of communicating at no extra cost. This means the reuse of sensing filter banks for transmission purpose also. But there was no consideration on the complexity issues associated with filter banks for CR. In this paper, we present a new low complexity reconfigurable filter bank architecture for multi-standard CR. The proposed filter bank is compared with other approaches and comparison results show that the proposed architecture is ideally suited for the CR systems.