A Direct Sampling Mixer with complex coefficient transfer function in 65nm CMOS

The Direct Sampling Mixer (DSM) with complex coefficient transfer function is demonstrated. The operation theory and the detail design methodology are discussed for the 2-parallel architecture, which can achieve large image rejection by introducing the attenuation pole at the image frequency band. The proposed architecture was fabricated in a 65nm CMOS process. The measured results agree well with the theoretical calculation, which proves the validity of the proposed architecture and the design methodology. By using the proposed design method, it will be possible for circuit designers to design the DSM with large image rejection ratio without repeated lengthy simulations.