Patent ID: 8736335
Filing Date: 2014-05-27
Classification: H03H

Abstract:
1. A front-end module comprising: an input terminal; one or more output terminals; a first filter circuit comprising a first input port and one or more first output ports and disposed between the input terminal and the one or more output terminals; a second filter circuit comprising a second input port and one or more second output ports and disposed between the input terminal and the one or more output terminals; a switch disposed between the input terminal and the first and second input ports, for connecting the input terminal selectively to the first and second filter circuits; and a matching circuit disposed between the one or more output terminals and one or more junctions between the one or more first output ports and the one or more second output ports, wherein the first filter circuit comprises a first filter element including a third input port and one or more third output ports, for passing a signal in a first passband, and wherein the second filter circuit comprises a second filter element including a fourth input port and one or more fourth output ports, for passing a signal in a second passband different from the first passband, and one or more first phase shifters disposed between the one or more fourth output ports of the second filter element and the matching circuit, and wherein a phase of a reflection coefficient in the first passband of the second filter element as seen from the one or more fourth output ports under a condition where the switch is switched to disconnect the input terminal from the second filter circuit, the one or more first phase shifters are removed, and the one or more junctions are opened, is leading, by 0° to 180°, a phase of a reflection coefficient in the second passband of the first filter element as seen from the one or more third output ports under a condition where the switch is switched to disconnect the input terminal from the first filter circuit and the one or more junctions are opened.