Hi guys,
Thanks for your reply. I would like to design a TRL calibration standard on a 400um sapphire substrate. There is no ground plane.
I am mainly wondering if there is a "general rule of thumb" for the design of parallel CPWs. For instance, can you guarentee at least 80dB or 90dB of isolation if the CPWs are N wavelengths apart, N * (2s + 2g) apart, or N times some other physical parameter apart?
Also, I don't have HFSS or any other program that costs money. I've tried simulating CPWs in Ansoft Designer SV, but I could never get reasonable results with comparsion to hand calcuations. I tried Sonnet Lite and simulated CPW that was within 5% of the values predicted by hand calculation, but with only 16MB of memory allocated for this free application, I couldn't simulate anything larger than a single CPW.