L-band wideband filter in 0.13 µm CMOS with high common-mode rejection

An L-band filter in 0.13 µm CMOS with high common-mode rejection over a wide bandwidth and high differential out-of-band rejection over a large frequency range is presented. The high common-mode rejection in the passband is realized by shifting the common-mode transmission zeros into the passband while maintaining the differential-mode bandpass response. The measured differential-mode insertion loss and return loss of the filter with 62% bandwidth from 1 GHz to 1.9 GHz are better than 3.2 dB and 12.3 dB respectively. The common-mode rejection is more than 23.5 dB up to 3.7 GHz.