This article presents an effective methodology for desigining a CMOS single-balanced down conversion mixer with LO cancellation for MB-OFDM UWB direct-conversion receiver. The most crucial drawback of single-balanced mixer: LO feedthrough is overcome by employing BPF tecnique for multi-channel LO signal. The proposed single-balanced mixer is implemented with 0.18 mu m CMOS technology and it operates from 3 to 5 GHz frequency range. The measurement result shows that LO signal amplitude is less than IF signal, 1 dBm at 4-GHz. band and the current consumption is 6 mA. (c) 2007 Wiley Periodicals, Inc.