A Bandwidth-Tunable Active Bandstop Filter Having Variable Loss Compensation Circuits

摘要

A bandwidth-tunable active bandstop filter with variable loss compensation circuits is presented in the paper. The active bandstop filter uses a dual-resonant circuit in the feedback path of the differential amplifier for tuning bandwidth as well as a series resonant circuit in the load for compensating losses. The implemented active bandstop filter has achieved a variable center frequency of 0.74 to 1.2GHz with a rejection level of 21.8 to 23.6dB. Moreover, the active bandstop filter has provided a 10dB fractional bandwidth of 41.8 to 74.2% with a rejection level of 13.6 to 33.6dB. Typical loss compensation was 10 to 16dB. This is the first time to present a bandwidth-tunable active bandstop filter having a variable loss compensation circuit.