High-Q gyrator-based monolithic active tunable bandstop filter

摘要

A monolithic bandstop active tunable filter has been designed andnrealised. The filter is based on a gyrator-type active resonator,nimplemented using only three active devices. The centre frequency of thenrealised notch filter is around 2.0 GHz, with a tuning range greaternthan 400 MHz. The chip dimensions are 1.2×1.2 mm2nincluding coplanar RF test pads. Measured performances of the realisednchip include a typical in-band rejection greater than 35 dB over all thenoperating bandwidth, a stopband span less than 50 MHz, together with anninput/output match greater than 14 dB. Positive supply only has beennemployed