From: Robert Badea <rxb230@ca...>  20120614 19:40:54

Hello, I was using your webpage on microstrips as an equation reference for some of my designs. I was wrestling with an issue I had today using the Hammerstad and Jensen quasi static characteristic impedance equations. I was using this page... http://qucs.sourceforge.net/tech/node75.html#SECTION001211000000000000000 The issue is you wrote down ZL(W,h,er) = ZL1/Sqrt[er] but its actually ZL1/Sqrt[ereff] where er is the relative permittivity and ereff is the effective permittivity provided later on by Hammerstad and Jensen, the effective permittivity is correct. ZL1 is the characteristic impedance of the strip its self, the dielectric substrate is factored in the effective permittivity using their model. I have not tried your simulator yet so I don't know if the issue carried over to the simulations. But I still wanted to say thank you for the webpage, it was extremely useful to have a compendium of references and equations all in one place so well organized. 