This sheet is used to design microwave Coupled filters.
The maths for this can be found at www.acusd.edu/~ekim/e194rfs01/iec19aek.pdf.I have also added some simulation results at the end.
There are three steps to this filter design:
Step 1
, Get the filter g-values, this sheet calculated the g values according to the Chebychev polynomial, but these can be obtained in a variety of ways from books or from a program freely available from my web page.You will be pleased to know that these g-values agree with my program!!
Step 2
, Calculate Zoo/Zoe and wavelength depending on the type of filter.
This MathCAD sheet stops at this point.
Step 3
, Calculate length and width.One method is to use Linecalc which is part of ADS.For microstrip designs I have written a MathCAD sheet which is available from my wepage that works well for thin tracks, less well for thicker tracks. Also you can try
transcalc.sourceforge.net
for a Linecalc equivalent.
Yellow is user input, Green is output