A Single-Layer Planar Wideband Filtering Single-Ended-to-Balanced Crossover With Excellent Common-Mode Suppression

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 69; no. 2; pp. 364 - 368
• Main Authors: Zheng, Yana, Wang, Weimin, Wu, Yongle, Chen, Weijuan
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Baluns; Bandwidths; Broadband; Common-mode suppression; Crossovers; Equivalent circuits; Fabrication; Filtering; Filtration; Frequency ranges; Integrated circuit modeling; path-isolation; Scattering parameters; single-ended-to-balanced crossover; single-layer; Wideband; Wireless communication systems
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2021.3100334

In this brief, a single-layer planar single-ended-to-balanced crossover has been proposed, which has a wideband filtering differential-mode response, wide path-isolation bandwidth, and an excellent common-mode suppression. The complete design procedure and rigorous derivations are demonstrated based on the even-/odd-mode analysis. A 3.5 GHz prototype has been designed, simulated and measured. Finally, the measured 15-dB differential-mode filtering bandwidth and 10-dB common-mode transmission bandwidth are 37.38% and 77.33%, respectively. Besides, a 117% bandwidth of 10-dB path-isolation is also achieved. Moreover, the bandwidth of 22-dB common-mode-to-differential-mode conversion is 143% over the frequency range of 1-6 GHz. This proposed crossover can be an excellent candidate for constructing balanced and unbalanced wireless communication systems.