KIRSCHNING AND JANSEN COMPUTER-AIDED DESIGN FORMULAE FOR THE ANALYSIS OF PARALLEL COUPLED LINES

Among the many computer-aided design (CAD) formulae used for the calculation of the wave parameters of coupled microstrip lines where fringing field effects occur, the Kirschning and Jansen equations are the most utilized ones, not only because of their high accuracy, but also because of their wide range of application. Here, we show that, despite the aforementioned advantages, such equations may lack physical meaning. We prove, for the first time, that the utilization of these widespread CAD equations can lead to positive valued mutual capacitances, an unacceptable result from the viewpoint of electromagnetic theory. (C) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 2466-2470, Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24659