Click here to go to our main page on coupled line couplers
Clicj here to learn about Henrik Forstén's on-line 2D EM field solver tool
Click here to see PolyStrata coax analyzed with an Henrik Forstén's on-line EM tool
Click here to see PolyStrata 10dB coupler design using Henrik Forstén's on-line EM tool
Click here to learn about the PolyStrata process
Click here to see a GaAs microstrip10dB coupler analysed with Henrik Forstén's tool
New for February 2026. There's nothing like being unemployed for making you look around for free EDA tools.
Here we are using Henrik Forstén's on-line 2D EM tool to follow up on a microstrip coupler design we first posted on this page using Microwave Office's linear model. Linear models are a reat way to start a design but before you fabricate anything you should take a look at the artwork with an electromagnetic solver. There are 3D simulators (HFSS, CST) and 2.5D simulators (Momentum), but how about a 2D solver? We took a look at the geometry using Henrik Forstén's totally free on-line 2D EM field solver tool. It is perfectly valid for transmission lines of uniform cross-section; if you need to analyze bends and other transitions you will have to find another way.
One of teh features of the tool is that you can store all of your parameters (geometry, material properties, frequqney points, etc) by copying a link to your work.
Here is the exact geometry we analyzed with Microwave Office on this page
Here is a link with all the parameters loaded
Click here
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Even and odd mode impedances. if you work out the math, even should be 69.4, odd 36.0. The resulig structure has Ze 67.7 and Zodd 35.2 at 10 GHz; oit's pretty close.
S-parameters​
Now lets compare the Microwave office coupler analsys with the EM analysis. We no longer have access to MWO, otherwise we would might have plotted all teh data on one plot. Here ie the MWO schematic. Port 1 is in input, 2 is iolated, 3 is dired and 4 is coupled.
Here is the Microwave office result