Design of CMOS active bandpass filter with three transmission zeros

摘要

An active bandpass filter with three transmission zeros is proposed. The filter consists of complementary cross-couple pairs to compensate resistive losses of resonators and a shunt-feedback inductor (L_P) to achieve the transmission zeros. The circuit is designed, implemented, and verified in a standard 0.18 μm CMOS process. The circuit with a chip size of 0.55×0.9 mm~2 draws 2.4 mA from a 2.1 V supply voltage. The measured insertion and return loss at 11 GHz is 1.7 dB and 26 dB. The rejection levels at these transmission zeros are greater than 12 dB. Moreover, the introduction of L_P demonstrates a 1.8 dB and 2.5 dB improvement in NF and linearity compared to the filter without L_P.