Using DC Block/Feed in ADS Schematic
DC Blocks which you place in labaratory is actually real capacitors which you use in circuits to prevent unwanted signals from entering to either port(terminal) of your device. Those components will be replaced by real inductors and capacitors serving the same purpose in your circuit.
When you talk about realistic, things get much more complicated; because now you have to think more than just designing(ie. tolerances of components effect your design, heat compensation techniques, so on so forth)
Even a DC block in real life has a model.If you would get a realistic results, you should always use equivalent models instead of ideal ones..
( I hope well understood your question )
We often design from "raw sketch" to accurate, fine detail.
For the early steps, we need to keep away DC bias from the 50 Ohm terminals, that's what a DC block is good for in simulation.
Thanks guys, I guess my labs in school just neglected to follow through with designing the circuit completely (to use volker@muehlhaus's terminology, we never really got past the "raw sketch" to make our designs "accurate w/ fine detail"