Re: phase shifter in ADS
You probably need to elaborate a little to get some more insight. But this may help out a little.
I did a switched path phase shifter in ADS for a MMIC. In that case, the hardest part was creating a good FET switch model. Once that is done, and you are fairly confident in it, then you put two switches back to back as close as is physically possible. Then, you extend one of the paths by your desired phase shift. You could use Momentum to simulated the line lengths, to ensure that you have the correct difference. Momentum will also help you if you need to wrap the line around to fit within a physical area.
You could also do something similar with a high and low pass filter, which both pass your Fo. You can tweak those out to give you a certain phase delay, which would accomplish the same thing.