Microminiature Transformers

Paper GV-15: To be presented at the 53rd Conference on Magnetism and Magnetic Materials, Austin, TX, Nov. 2008

On Design of Air Core Ethernet Transformers

D. Bowen1,2, I. Mayergoyz1,2, C. Krafft3, D. Kroop4, M. Beyaz1

1. Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA
2. UMIACS, University of Maryland, College Park, Maryland 20742, USA
3. Laboratory for Physical Sciences, College Park, Maryland 20740, USA
4. Windermere/Essex, Subsidiary of Northrup Grumman, Annapolis, MD 21401, USA

Abstract

The air-core designs of Ethernet transformers in which the reduction of winding magnetic

coupling is compensated by increasing the cross-winding capacitance coupling are discussed. The

theoretical analysis that accounts for the distributed nature of the cross-winding capacitance is

presented. It is demonstrated that the capacitive cross-winding coupling may result in desirable

transfer characteristics of air-core transformers that are similar to those of ferrite core Ethernet

transformers.