Differential microstrip lines with common-mode suppression based on electromagnetic band-gaps (EBGs)
Vélez Rasero, Paris (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Bonache Albacete, Jordi (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Martín, Ferran, (Martín Antolín) (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)

Date:	2015
Abstract:	A technique for the suppression of the common mode in differential (balanced) microstrip lines, based on electromagnetic band-gaps (EBGs), is presented in this letter. It is demonstrated that by periodically modulating the common-mode characteristic impedance of the line and simultaneously forcing the differential-mode impedance to be uniform (and equal to the reference impedance of the differential ports), the common mode can be efficiently suppressed over a certain frequency band, while the line is transparent for the differential-mode. The main advantage of EBGs, as compared to other approaches for common-mode suppression in differential microstrip lines, is the fact that the ground plane is kept unaltered. Moreover, the design of the differential line is straightforward since the required level of common-mode suppression and bandwidth are given by simple approximate analytical expressions. As a design example, we report a four-stage common-mode suppressed differential line with 68% fractional bandwidth for the common-mode stopband centered at 2. 4 GHz, and maximum common-mode rejection ratio (CMRR) of 19 dB at that frequency. Furthermore, we have designed and fabricated a six-stage double-tuned common-mode suppressed differential line in order to enhance the stopband bandwidth for the common mode around 2. 4 GHz.
Grants:	Ministerio de Ciencia e Innovación TEC2010-17512 Ministerio de Ciencia e Innovación CSD2008-00066 Ministerio de Ciencia e Innovación TEC2013-40600-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-157 Agència de Gestió d'Ajuts Universitaris i de Recerca 2019/SGR-421
Note:	CIMITEC
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió sotmesa a revisió
Subject:	Common-mode noise suppression ; Differential transmission lines ; Electromagnetic band-gaps (EBGs) ; Periodic structures
Published in:	IEEE antennas and wireless propagation letters, Vol. 14 (2015) , p. 40-43, ISSN 1536-1225

DOI: 10.1109/LAWP.2014.2354472

Pre-print 4 p, 1.7 MB

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