A monolithic active notch tunable filter based on the gyrator principle

A monolithic bandstop active tunable filter has been designed and realised. The filter is based on a gyrator-type active resonator, implemented using only three active devices. The center frequency of the realised notch filter is around 1.9 GHz, with a tuning range of more than 400 MHz. Measured performances include a typical in-band rejection of more than 30 dB all over the operating bandwidth, a stopband span of less than 50 MHz, together with input/output match better than 12 dB. Positive supply only has been employed.