a question about microstrip on pcb.

[ArmBoy]

hi, i have a question about microstrip on pcb. when talking about microstrip on pcb, we may focus on phase vilocity and calculate the
time delay between source and load, what i want to know is that if the
working freq of my digital system is 100M, what is the rf freq i should
assume when dealing with microstrip.

 

[flatulent]

at least the 5th harmonic

One parameter of interest is the rise time you have to meet. Another is the 5th harmonic of a square wave (or 2.5 times the pulse rate) which is usually the minimum required to get a useful pulse shape. If you want to be precise, calculate the delay of all harmonics of your signal and add them up at the far end to produce the received pulse shape. from this you can do a second order correction on the pulse velocity on your line.

 

[toonafishy]

On the other hand if your data stream can contain a long string of 0s or 1s, then the frequency can at times look much lower than 100M. You must also consider this.