A Q-enhanced 8th order CMOS active bandpass filter is presented employing a novel two-stage self-calibration technique. The proposed active filter shows the better out-band attenuation performance than other reported CMOS active bandpass filters. The proposed calibration method enables the stable filtering operation affected by neither the input power variation nor the strong interference power. It is fabricated using 65 nm CMOS process. The measured 3 dB bandwidth is 54 MHz at 2.37 GHz. The insertion loss is 2.9 dB and the out-band attenuation is 27.5 dB at 15 MHz offset frequency. The performance of the filter remains unchanged for 5% supply voltage variations.

An empirical dispersion formula is proposed and experimentally verified considering higher order modes of the conductor-backed coplanar waveguide with via holes. For this purpose, an effective dielectric constant is extracted up to 100 GHz from measured S-parameters. By fitting the extracted data, an empirical equation is extracted. The simulation of the Gaussian pulse transmission and the comparison results with the modeling data validate the reported expression.