ALEXANDRIA, Va., June 16 -- United States Patent no. 12,308,815, issued on May 20, was assigned to Apple Inc. (Cupertino, Calif.).

"Differential double balanced duplexer" was invented by Christof Pfannenmuller (Erlangen, Germany), Joonhoi Hur (Sunnyvale, Calif.), Dominic Koehler (Viereth-Trunstadt, Germany), Harald Pretl (Schwertberg, Austria) and Rastislav Vazny (Sunnyvale, Calif.).

According to the abstract* released by the U.S. Patent & Trademark Office: "A differential double balanced duplexer (dDBD) includes a transmitter and a first balun are coupled to a first impedance tuner that produces a first impedance that blocks received signals at a first frequency range from travelling across the first balun and into the transmitter, and a...