Wrangler236
Newbie level 3
Hello,
I'm just getting into analog RF design(L-band). I have done a lot of high speed digital stuff > 10Gb/s on differential pairs.
Typically we would call up the anticipated PCB manufacturer and get a stackup that they generated using their process and tools. For example 100 ohm differential space and trace numbers. We would then have the PCB layout team use these numbers.
In getting into the RF realm we've noticed a lot of VSWR across the band of our first board. Some of this was component pad size etc.
I realized we needed to develop with an EM solver. But since we get the stackup from the fabricator it doesn't agree with the stackups generated in the tools. I talked to their engineering dept. and there was what I felt a lot of hand waving. One thing that came out of it was they test using a TDR that only goes up to ~700MHz. I take that as my 950-2150MHz board isn't being verified at the correct frequencies. Is this correct?
The other thing was there doesn't seem to be a way to connect their process stackup numbers to the simulation tools. How does the industry use the simulation tools to design boards that are then fabricated as designed?
Thanks
Matt
I'm just getting into analog RF design(L-band). I have done a lot of high speed digital stuff > 10Gb/s on differential pairs.
Typically we would call up the anticipated PCB manufacturer and get a stackup that they generated using their process and tools. For example 100 ohm differential space and trace numbers. We would then have the PCB layout team use these numbers.
In getting into the RF realm we've noticed a lot of VSWR across the band of our first board. Some of this was component pad size etc.
I realized we needed to develop with an EM solver. But since we get the stackup from the fabricator it doesn't agree with the stackups generated in the tools. I talked to their engineering dept. and there was what I felt a lot of hand waving. One thing that came out of it was they test using a TDR that only goes up to ~700MHz. I take that as my 950-2150MHz board isn't being verified at the correct frequencies. Is this correct?
The other thing was there doesn't seem to be a way to connect their process stackup numbers to the simulation tools. How does the industry use the simulation tools to design boards that are then fabricated as designed?
Thanks
Matt