What is a 50 Ω feedthrough, and why do I need one?
A 50 Ω feedthrough is essentially a 50 Ω resistor to ground, in parallel with whatever you have connected through it. This means that if the impedance of the circuit you’ve hooked up to it is much higher than 50 Ω, the net result of 50 Ω in parallel with the higher impedance will look a lot more like 50 Ω than the high impedance. Matching is crucial for success in radio frequency (RF) circuits. Because the signals we’re working with have wavelengths on the order of or less than the lengths of board components, we’re facing transmission lines at every turn instead of the lumped circuits that you’ve been dealing with until now. This means it’s possible for us to fit multiple wavelengths of a signal on things like capacitor legs, board traces, and BNC cables, which will behave like transmission lines instead of just a point or short. Thus, we have to make sure we eliminate reflections and standing waves that can occur in these transmission line segments. From your E&M classes, you may rem
