A filter chip lying on an upper surface of a top layer package substrate is connected to an upper surface ground electrode ( 235 ). The upper ground electrode ( 235 ) and a lower surface ground electrode ( 237 ) are connected to each other via through electrodes ( 261, 262, 263 ), ground wiring patterns ( 251, 252 ), first connecting lines ( 271 to 276 ), and second connecting lines ( 281, 282 ). The first connecting lines ( 271 to 276 ) are connected to the ground wiring patterns ( 251, 252 ), whereas the second connecting lines ( 281, 282 ) are not connected to the ground wiring patterns ( 251, 252 ), respectively. Owing to the provision of the connecting lines connected to the ground wiring patterns ( 251, 252 ) and the connecting lines unconnected to the ground wiring patterns ( 251, 252 ), the impedance between a multilayer package substrate and ground can be adjusted.
1. A duplexer, comprising:
a multilayer package substrate having a plurality of package substrates laminated on one another;
a surface acoustic wave filter chip disposed on an upper surface of the package substrate corresponding to a top layer;
an upper surface ground electrode formed on the upper surface of the package substrate corresponding to the top layer and connected to ground electrodes of the surface acoustic wave filter chip;
a lower surface ground electrode formed on a lower surface of the package substrate corresponding to a bottom layer;
ground wirings formed on at least one junction face of respective junction faces of the plurality of package substrates and connected to the upper surface ground electrode and the lower surface ground electrode via through electrodes provided in the multilayer package substrate;
one or a plurality of first connecting lines provided on the side surfaces of the multilayer package substrate and connected to some or all of the ground wirings and the upper surface ground electrode and the lower surface ground electrode; and
one or a plurality of second connecting lines provided on the side surfaces of the multilayer package substrate, said one or plural second connecting lines being connected to the upper surface ground electrode and the lower surface ground electrode and unconnected to the ground wirings.
2. A duplexer according to claim 1 , wherein the first connecting lines are connected to all the ground wirings.