HEMT Wafer Probe Card Layout

[tec5c]

I have some spare panel room on a design I'm getting fabricated and I want to utilise this space. I would like to create a test jig for the HEMT I am using which I can measure its parameters using wafer probes at my University.

Things I know:
3 probe setup - G S G
Dimensions of probes for probe pads; width, spacing etc
RF measuring layout pattern; given in datasheet.

What I am unsure of is how to combine the dimensions into a layout.

I found this in a Cascade Microtech app. note, I believe this is what I need to do?



This is my attempt, as you can see it didn't work out.



The probe pads (G S G) are 100 micron squares, with a spacing of of 200 microns from edge to edge. The HEMT device has pin sizes of ~740 microns wide, which I why the tapered lines were included. However, the wafer probe pads are spaced at 200 microns (edge to edge) apart. This results in the tapered line from Gate/Drain pins overlapping with the ground strips for the two Source pins. (my apologies for the crude drawing)

Any advice on where I am going wrong? 

EDIT: I just noticed that the dimensions for the spacing between the Drain and Gate probe pads is incorrectly labelled in my diagram (I said it was crude!  ). It should be 2.06mm/2060 microns