Dual-band mixer and its design flow

In the dual-band mixer of this invention, a current combined load is presented and is shared by two separate working frequency bands. In the invented dual-band mixer, a switch is provided to connect and disconnect an adjust capacitor series to the load inductors. By determining the capacitance of respective capacitors and the inductance of the load inductors, it is possible to generate resonance with related parasitic capacitances at particular frequencies, such that value of the load inductors may be changed. This enables the invented mixer to work with selected frequencies according to the operation of the switches. In addition, a systematic methodology is proposed to implement the design of the invented dual-band mixer. The efficient design method is approved by a 2.4/5.2-GHz CMOS mixer implementation.