anh56789
Junior Member level 2
Hi everyone,
I’m designing an amplifier using 65nm CMOS technology at 30GHz, with a substrate stack-up as shown in the figure below (I can’t disclose the full substrate details due to an NDA). The substrate thickness is 700um. I need to run an EM simulation for the amplifier up to 60GHz to account for the second-order harmonic, but I’m encountering difficulties in setting up the EM simulation, particularly with selecting the appropriate port type. The documentation indicates that the distance between the (+) and (-) of a port should be smaller than lambda/10, which is 500um at 60GHz. Since my substrate thickness is 700um, I suspect that the implicit ground port might not be suitable for this simulation, but I’m unsure. I have a few questions and would appreciate your guidance:
I’m designing an amplifier using 65nm CMOS technology at 30GHz, with a substrate stack-up as shown in the figure below (I can’t disclose the full substrate details due to an NDA). The substrate thickness is 700um. I need to run an EM simulation for the amplifier up to 60GHz to account for the second-order harmonic, but I’m encountering difficulties in setting up the EM simulation, particularly with selecting the appropriate port type. The documentation indicates that the distance between the (+) and (-) of a port should be smaller than lambda/10, which is 500um at 60GHz. Since my substrate thickness is 700um, I suspect that the implicit ground port might not be suitable for this simulation, but I’m unsure. I have a few questions and would appreciate your guidance:
- If I use the implicit ground port, will ADS generate any warning messages in the EM log about this potential port size violation?
- If I need to use an explicit ground port, what should I select as the reference point? I’m uncertain because I’m working with multiple transistor and capacitor models connected to the EM layout, which only includes interconnects and inductors. For a CPW transmission line, selecting the reference point seems straightforward (the nearby ground plane), but I’m unclear on how to define reference points for other devices.