A 2.45/5.2 GHz Image Rejection Mixer With New Dual-Band Active Notch Filter

A 2.45/5.2 GHz dual-band Gilbert downconversion mixer with image rejection function is presented, which is implemented using the 0.18 mum CMOS technology. The proposed differential dual-band image rejection circuitry is employed for the 2.45/5.2 GHz WLAN application to effectively diminish the DC power consumption and complexity of circuit design compared to the traditional Hartley or Weaver architectures. Moreover, the cross-connected pair consisted of NMOS and PMOS transistors in the proposed notch filter will further ameliorate the image rejection capability. The IC prototype achieves conversion gain of 10.5/11 dB, IIP3 of -4.9/-5.2 dBm for RF = 2.45/5.2 GHz and IF = 500 MHz while the image rejection ratio is better than 36/45 dB in the whole operation bandwidth.