Narrow band MMIC active filter using negative resistance circuits in coplanar line technique

A narrow band second order active bandpass filter has been developed in coplanar line technique using negative resistance circuits. This filter has a tunable centre frequency from 1.92 GHz to 2 GHz, a 3 dB bandwidth of 24 MHz, which is about 1.2% of the centre frequency. It is fabricated on a GaAs substrate and occupies an area of 1.35 × 1.75 mm2 on the wafer including all biasing elements.