I've got a GPS circuit where the antenna is connected directly to the GPS receiver via a coplanar waveguide designed for an impedance of 50ohms. Unfortunately, I neglected to add the bias-t circuit that is used to provide power to the GPS antenna. Luckily, I was able to remedy this problem on the prototype by breaking the transmission line, soldering a 22pF cap across the gap and connecting the antenna side directly to a nearby 3.8V trace on the PCB. The GPS was able to get a fix in about 20s and happily tracked 9 satellites.
I now need to incorporate the capacitor and inductor of the bias-t into the circuit (Reference Design page 150) and I was wondering what considerations I need to make in order to ensure that the transmission line remains at 50ohms?