Improved support for couplers

Recently support for directional couplers has been much extended. Its now possible to desgin couplers, determine the properties of couplers on PCBs, find a microstrip coupler on a PCB that suits your requirments. See http://atlc.sourceforge.net/couplers.html

Now its possible to design a coupler with a given frequency response and coupling factor. For one geometry (coupled striplines) it's possible to quickly find the dimensions of the coupler to meet the required specification. See http://atlc.sourceforge.net/determine_dimensions_of_couplers.html

If the user wishes to use coupled striples on a PCB, then this can be designed too, although this is a CPU intensive process, taking several hours to find the optimal PCB layout