Program Overview

MStrip+is an interactive transmission line design program for the RF/Microwave engineer. It allows you to analyze or synthesize microstrip, including the effects of dispersion, (caused by frequency), and cover height, coupled microstrip with close to Bryant-Weiss accuracy, stripline, coupled stripline, or suspended substrate lines.

The calculations performed by MStrip+ are far beyond anything that can be done by hand, and are highly accurate. The synthesis techniques used here are, for the most part, unique, and have been the subject of several technical papers in the trade journals. No more accurate line synthesis techniques are known to exist.

This manual assumes a basic familiarity with transmission line structures. However, each of the different line types will be discussed in detail, and numerous examples will be given. After working thru the pages to follow, you should acquire a good feel for the dimensional and electrical parameters involved.

Background Information

The single microstrip line routine in MStrip+ employs a two-tiered iterative loop, and, relative to the highly regarded pioneering work of Bryant & Weiss (1968), and their MSTRIP program, is unsurpassed in overall accuracy. This program is named in their honor. The technique employed became a virtual standard in the industry following its publication in 1985 as the "MS" program. See Appendix C. RF & Microwaves magazine was flooded with thousands of requests for copies from engineers worldwide.


Since the publication of the original piece mentioned above, highly accurate dispersion and cover height routines have been added to markedly enhance the capabilities of "MS."

The microstrip coupled-line synthesis routine is based on the work of Zehentner, (see Appendix C), who fit a pair of fifteen-term polynomials to thousands of data points generated by the venerable Bryant & Weiss MSTRIP program in 1980. Its been shown to be far superior to earlier methods. Indeed, the earlier synthesis technique is now only used to generate seed values for use as a starting points by this new iterative routine!

The stripline and coupled-stripline routines use closed form equations which, in one form or another, have long been staples of the industry. They are based on the work of Cohn, an early pioneer in the field. See Appendix C. In the days before the advent of the desktop computer, these now "simple equations" were thought by many back then to be too lengthy, and were often translated into nomographs!

Lastly, the suspended substrate routine is based on infinite series expressions, which were developed by Yamashita and Atsuki in 1970. See Appendix C. Considerable work went into the formulation of the iterative loop technique used, and the method by which seed values were generated. This program has been used extensively, with good results, in the design of microwave filters in the 8-30 GHz range.

Rest assured - you're in good hands with MStrip+ !

Note: Your screen display will be in a black DOS window. We use color boxes, on occasion, to make the menus and tabular output stand out from the white page background.