Compact Configuration for Common Mode Filter Design based on Planar Electromagnetic Bandgap Structures

• Published in: IEEE transactions on electromagnetic compatibility Vol. 54; no. 3; pp. 646 - 654
• Main Authors: de Paulis, F., Raimondo, L., Connor, S., Archambeault, B., Orlandi, A.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Cavity resonators; Circuit properties; Common mode (CM); Delta modulation; Electric connection. Cables. Wiring; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; electromagnetic bandgap (EMG); electromagnetic compatibility (EMC); Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Frequency filters; Layout; Materials; Metamaterials; Noise; Periodic structures; power integrity (PI); Printed circuit boards; signal integrity (SI); Solids; Studies; Various equipment and components; On board equipment; Photonic band gap; Plane configuration; Electromagnetism; Differential amplifier; Resonant coupling; Printed circuit board; Electromagnetic compatibility; Compact design; electromagnetic bandgap (EMG); electromagnetic compatibility (EMC); Mode filter; power integrity (PI); Time domain method; Cavity; Photonic crystal; Layout; Electrical connector; High speed; Common mode (CM); Printed circuit; signal integrity (SI); Signal integrity; Planar technology
• ISSN: 0018-9375; 1558-187X
• DOI: 10.1109/TEMC.2011.2170427

A planar electromagnetic bandgap configuration of a compact common mode filter that is laid out on printed circuit board is studied. This filter is used to mitigate the common mode noise traveling on high-speed differential signal traces. These differential signal lines may be connected to I/O connectors and cables and small amounts of common mode noise can result in significant electromagnetic emissions. The filter is obtained by a very simple planar geometry based on the electromagnetic bandgap structures. A cavity made by a rectangular/square patch (together with a solid plane underneath) has a well known and predictable resonant behavior; the coupling between the differential pair routed on top of the patterned plane and the patch cavity, occurring when the traces cross the gap between adjacent patches, is used to reduce the energy associated with the propagation of the common mode noise. The properties of this filter are studied taking into account the layout of a real differential microstrip and the number of gap crossings. A compact configuration is proposed. Time domain simulations validate the suggested layout approach.