Multiplexer, transmission apparatus, and reception apparatus

Abstract

A multiplexer includes filters and a common terminal connected to an antenna element by a connection path, a first inductance element being connected between the connection path and a reference terminal. A terminal closer to the antenna element among an input terminal and an output terminal of one filter among the filters is connected to a parallel resonator and is connected to the common terminal with a second inductance element interposed therebetween. A terminal closer to the antenna element among an input terminal and an output terminal of each of other filters other than the one filter among the filters is connected to the common terminal and a series resonator.

What is claimed is: 
     
         1 . A multiplexer that transmits and receives a plurality of high-frequency signals, the multiplexer comprising:
 a plurality of elastic wave filters that have pass bands different from one another;   a common terminal that is connected to a connection path that connects to each of the plurality of elastic wave filters; and   an inductance element connected between the connection path and a reference terminal.   
     
     
         2 . The multiplexer according to  claim 1 , wherein the plurality of elastic wave filters includes a Band 25 transmission filter. 
     
     
         3 . The multiplexer according to  claim 1 , wherein the plurality of elastic wave filters includes a Band 66 transmission filter. 
     
     
         4 . The multiplexer according to  claim 1 , wherein the plurality of elastic wave filters includes a Band 25 reception filter. 
     
     
         5 . The multiplexer according to  claim 1 , wherein the plurality of elastic wave filters includes a Band 66 reception filter. 
     
     
         6 . The multiplexer according to  claim 1 , wherein each of the plurality of elastic wave filters includes at least one surface acoustic wave resonator that includes a piezoelectric substrate and an interdigital transducer electrode. 
     
     
         7 . The multiplexer according to  claim 5 , further comprising a mounting substrate on which the at least one surface acoustic wave resonator is mounted. 
     
     
         8 . The multiplexer according to  claim 7 , further comprising a sealing resin disposed on the mounting substrate and covering the at least one surface acoustic wave resonator. 
     
     
         9 . The multiplexer according to  claim 7 , wherein the mounting substrate includes a multilayer structure. 
     
     
         10 . The multiplexer according to  claim 9 , wherein the mounting substrate includes the inductance element. 
     
     
         11 . The multiplexer according to  claim 9 , wherein the mounting substrate includes a second inductance element that is connected to one of the plurality of elastic wave filters.