X-Band Quasi-Elliptic Non-Reciprocal Bandpass Filters (NBPFs)

• Published in: IEEE transactions on microwave theory and techniques Vol. 69; no. 7; pp. 3255 - 3263
• Main Authors: Ashley, Andrea, Psychogiou, Dimitra
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Band-pass filters; Bandpass filter (BPF); Bandpass filters; Circuit design; Design; Impedance; integrated circuit; isolator; Isolators; miniaturization; MMIC (circuits); MMIC filter; Noise measurement; non-reciprocal filter; Power transmission; Radio frequency; Resonators; RF co-design
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2021.3081021

This article reports on the design and practical development of RF co-designed MMIC components that exhibit the function of a bandpass filter and an RF isolator. They are based on cascaded non-reciprocal frequency-selective stages (NFSs), one-pole/two-transmission zero (TZ) multi-resonant stages, and impedance inverters. The combination of these components results in a two-port network that exhibits a nonreciprocal quasi-elliptic bandpass filter (NBPF) response in the forward direction and full RF signal cancellation in the reverse one. The operating principles of the NBPF are presented through various circuit-based design examples of low- and high-order configurations. For proof-of-concept demonstration purposes, NBPF prototypes were designed on an MMIC GaAs process and were experimentally validated at <inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula>-band. They include a two-pole/two-TZ NBPF and a three-pole/four-TZ NBPF.