Tunable high-Q MMIC active filter by negative resistance compensation

This paper describes the techniques for realizing MMIC active filter using negative resistance to compensate the loss from the spiral inductor, in order to achieve high Q-value performance. The active coupled approach and common-gate FET with an inductive feedback configuration have been used in this study. The measured response of this filter exhibits the pass-band tuning range from 1.855 GHz to 2.14 GHz with a Q-value of 100. This filter has also been characterized by digital modulation signal.