Synthesis Design on Wideband Single-Ended and Differential Dual-Band Filtering Impedance Transformer

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 68; no. 3; pp. 913 - 917
• Main Authors: Chen, Weijuan, Wu, Yongle, Wang, Weimin, Xu, Kai, Shi, Jin
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">J -inverters; Band-pass filters; Bandpass filters; Broadband; Circuit design; Dual band; filtering; Frequencies; Impedance; impedance transformer (IT); Resonators; Scattering parameters; Transformers; Transmission lines; Wideband
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2020.3022464

In this brief, a novel dual-band wideband impedance transformer (IT) integrated with the function of dual-band bandpass filtering was proposed for the first time. The presented design, based on the equivalents of dual-band J-inverters and LC resonators, has a simple structure with parallel open/short-circuited stubs and cascading transmission lines. Analysis results show that the considered ITs can work at two separate uncorrelated frequency bands with arbitrary terminated real impedances. For demonstration, a wideband single-ended dual-band filtering impedance transformer (DBFIT) with the filtering order n = 4, and a differential DBFIT with n = 3, are designed. In particular, the common-mode rejection of the differential circuit is well considered. The simulated and measured results are recorded in good agreement, well verifying the design concept.