Recent advances in microwave active filter design. Part 1: Low-frequency techniques and noise optimization

Abstract

This two-part article presents a representative sample of recent advances in microwave active filter design. In part one, we discuss design techniques based on both analog and digital low-frequency methods that have been adapted to microwaves. From circuits with analog origins, we present simulated results, with some experimental verification, for a frequency-dependent negative resistance (FDNR) and active-inductance MMIC bandpass filters. From circuits with digital origins, we present experimental results for recursive filters, including MMIC bandpass and bandstop structures as well as higher-order cascaded sections. Part one concludes with a discussion of the noise-wave formalism and experimental results for active-recursive and tunable ring-resonator filters with minimum noise figure. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 159–176, 2002.