GYRATOR-BASED BIQUAD FILTERS AND NEGATIVE IMPEDANCE CONVERTERS FOR MICROWAVES

We develop and evaluate a new family of active-RC, gyrator-based, volt age-mode, biquadratic filters capable of realizing all standard second -degree filtering functions at microwave frequencies. Each biquad empl oys two negative second-generation current conveyors (CCII-s) or, equi valently, two infinite-conductance transistors, and we obtain excellen t simulated results by implementing each of these perfect elements as a cascaded pair of MMIC GaAs FETs. The transistors in the simulation a re modeled using tabulated S parameters of MB3000 (Phillips) devices. In addition, we catalog all known ideal, two-transistor negative imped ance converter (NIC) topologies and we show that some are intrinsicall y better than others with respect to their performance when the active elements are implemented using MMIC GaAs FET CCII-s. (C) 1998 John Wi ley & Sons, Inc.