I'm daydreaming a new product, and this is one problem:
The IC that I want to drive will be about a 2 pF load, and that wrecks the 50 ohm microstrip transmission line that connects the two SMAs. The idea is that a user can input a signal and either loop it into another (several?) boxes, or screw on a terminator.
The 2 pF makes really bad stuff happen around 2 GHz or so, for the loop-through path, and I'd like to go to 5. What I need is a zero-capacitance buffer.
A phemt source follower might work, with a SAV551 or one of the Skyworks parts. But fast source followers are also known as oscillators.
Maybe I could use a series resistor into a 50 ohm MMIC amplifier. I'd lose some signal but at least wouldn't have the horrible resonances that a lumped capacitor makes.