Hi gang,
I'm trying to find out why people use CPWs on PCBs.
I'm looking into improving the rise-time performance of a PCB. It is
currently using microstrip on 6.6mils of Rogers 4450B, with a ground
plane right underneath.
We are launching a 50ps step and getting 150ps out at the other end.
The path is about 5 inches long, an 11 mils trace with a nominal
impedance of 50ohms.
The test report from the PCB shop shows we are within 5% of 50ohms.
This is measured, not calculated.
The 150ps figure comes from the lab. Our early simulations showed
there would be rise-time degradation, but not at this level.
So I'm trying to educate myself on CPWs, I'm reading Microwave
Engineering by Pozar.
But I'd like a pre-digested answer like: it makes no difference, it
helps in the high frequencies, your 11mil traces are too thin, etc...
TIA
I'm trying to find out why people use CPWs on PCBs.
I'm looking into improving the rise-time performance of a PCB. It is
currently using microstrip on 6.6mils of Rogers 4450B, with a ground
plane right underneath.
We are launching a 50ps step and getting 150ps out at the other end.
The path is about 5 inches long, an 11 mils trace with a nominal
impedance of 50ohms.
The test report from the PCB shop shows we are within 5% of 50ohms.
This is measured, not calculated.
The 150ps figure comes from the lab. Our early simulations showed
there would be rise-time degradation, but not at this level.
So I'm trying to educate myself on CPWs, I'm reading Microwave
Engineering by Pozar.
But I'd like a pre-digested answer like: it makes no difference, it
helps in the high frequencies, your 11mil traces are too thin, etc...
TIA