A New Class of Low-Loss High-Linearity Electronically Reconfigurable Microwave Filter

• Published in: IEEE transactions on microwave theory and techniques Vol. 56; no. 8; pp. 1945 - 1953
• Main Authors: Peng Wen Wong, Hunter, I.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.08.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Band pass filters; Bandpass filter; Bandwidth; Circuit optimization; Circuit properties; Circuits; Circuits of signal characteristics conditioning (including delay circuits); Coupling circuits; Delay; Electric, optical and optoelectronic circuits; Electronic circuits; electronically tunable filters; Electronics; Exact sciences and technology; Feasibility; Frequency filters; Joining; Linearity; low-distortion tunable filter; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwave filters; Microwaves; Noise levels; Oscillators, resonators, synthetizers; Passband; Resonator filters; switched delay lines; Switching; Tunable circuits and devices; Tuning; Electronic control; switched delay lines; Tunable circuit; Resonator; Prototype; Third order; Lossy medium; low- distortion tunable filter; Microwave filter; Switching; Bandpass filter; electronically tunable filters; Intercept point; Tunable filter; Linearity; Band pass filter; Feasibility; Passband; Delay line; Microstrip circuits
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2008.927395

A novel electronically reconfigurable microwave bandpass filter based on a switched delay-line approach is presented. In contrast to conventional tunable filters, the approach enables the lossy and nonlinear switching elements to be used as part of the coupling elements rather than within the resonators. Therefore, the filter distinguishes itself through its ability to provide a wide tuning bandwidth with low passband loss and high linearity. Theoretical analysis of the approach is presented in this paper. The feasibility of the approach has been experimentally verified with microstrip circuit prototypes. The filter produced a maximum passband loss of 1.7 dB and a third-order intercept point of >32 dBm with 35% tuning bandwidth.