A rectenna, which can also be referred to as a rectifying antenna, sensor dish, or radar dish, was a specific kind of sensor that was placed on a starship. Its function was to locate and lock onto enemy ships.
The Millennium Falcon—a heavily modified YT-1300 light freighter that belonged to Han Solo, who was a smuggler—featured a circular, military-grade rectenna during the era of the Galactic Civil War. Nevertheless, this dish was broken off during the Battle of Endor. Consequently, Solo needed to swap it out for a rectangular, civilian version, but that one also broke off in the Battle of Crait. Subsequent to the Battle of Crait, the civilian rectenna was substituted with a circular, military-grade rectenna that was similar to the original.