Microwave, biquadratic, active-RC filter development

✍ Scribed by Stephen E. Sussman-Fort; Laurent Billonnet; Bernard Jarry

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 267 KB
• Volume: 8
• Category: Article
• ISSN: 1096-4290
• DOI: 10.1002/(sici)1099-047x(199803)8:2<102::aid-mmce4>3.0.co;2-p

✦ Synopsis

We present a number of computer-simulated results for a recently developed family of active-RC, microwave, biquadratic filters. These circuits are gyrator-based and ( ) contain negative second-generation current conveyors CCIIIs realized as cascades of MMIC GaAs FETs. First, the circuit family is extended to include asymmetric band-reject filters. As with the previous circuits of the group, we use optimization to obtain an accurate frequency response when the CCIIIs are implemented as cascaded pairs of GaAs FETs. Second, we illustrate how cascades of three or four devices become necessary for the CCIIIs of bandpass biquads as their center frequencies are increased. Next, we show how third-and fourth-order filters may be obtained by cascading optimized lower-order sections. In our examples, the slight interaction between the stages is eliminated by adjusting a single element. Finally, we discuss the topological origins of the biquad family and consider alternative circuit structures which may possess particular practical advantages.