Patent ID: 7501912

Claim:
A radio frequency (RF) signal processing device, the device comprising: a common terminal; a plurality of filters, wherein each of the filters is one of a surface acoustic wave (SAW) filter, a bulk acoustic wave (BAW) filter, and a thin film bulk acoustic resonator (FBAR) filter; a plurality of matching capacitors corresponding to the plurality of filters, each capacitor having a first electrode directly connected to the corresponding filter and having a second electrode, wherein the second electrodes of all of the matching capacitors are directly connected together to the common terminal; and one of an inductor and a transmission line connected between the common terminal and ground, wherein capacitance values (C 1m , C 2m , . . . , C nm ) of the n matching capacitors solve the equations: (2πF 1 ) 2 L(0+C 2 +C 3 + . . . +C n-1 +C n )=1; (2πF 2 ) 2 L(C 1 +0+C 3 + . . . +C n-1 +C n )=1; . . . (2πF n ) 2 L(C 1 +C 2 + . . . +C n-1 +0)=1, wherein C i =(C im *C i0 ) / (C im +C i0 ), wherein C i0 is the equivalent capacitance value of filter i outside of its passband, wherein L is an inductance value of the one of an inductor and a transmission line connected between the common terminal and ground, and wherein (F 1 , F 2 , . . . F n ) are center frequencies of the n filters.