Looking for an "SMA signal polarity inverter"
How it works: the black component in the middle is a balun (a type of transformer for RF applications). The input goes to ground trough the primary, inducing a voltage into the secondary. By connecting the right end of the secondary to the output and the other to ground, the signal gets inverted. Reflections, distortion and attention are minimized by selecting a balun that presents an impedance at the signal frequency which matches that of the transmission line (50 ohms).  

The attenuator is responsible for the 10 db attenuation you see.