US Patent 10560129 Hybrid-coupler-based radio frequency multiplexers

A radio frequency (RF) multiplexer includes, for example, a common port, a first port for a first frequency band, a second port for a second frequency band, and a third port for a third frequency band. The RF multiplexer also includes, for example, a first quadrature hybrid coupler (QHC), a second QHC and a third QHC. A coupling of the first QHC, a first pair of filters, and the second QHC separates the first frequency band and the second frequency band from the common port to the first port and to the second port, respectively. A coupling of the first QHC, a second pair of filters, and the third QHC separates the first frequency band and the third frequency band from the common port to the first port and to the third port respectively.