Surface acoustic wave device and branching filter

A surface acoustic wave device comprising:

• an input signal electrode and an output signal electrode to and from which an electric signal is inputted or outputted;
• a first surface acoustic wave resonator connected between the input signal electrode and the output signal electrode;
• and
• a second surface acoustic wave resonator including:
• a plurality of signal-side terminals having a plurality of comb electrodes and connected to a midpoint between the input signal electrode and the first surface acoustic wave resonator and a midpoint between the output signal electrode and the first surface acoustic wave resonator, and
• a ground-side common terminal having a plurality of comb electrodes to form interdigital transducers in cooperate with the comb electrodes of the plurality of signal-side common terminals and connected to a grounding electrode.

A surface acoustic wave device comprising:

• an input signal electrode and an output signal electrode to and from which an electric signal is inputted or outputted;
• a plurality of first surface acoustic wave resonators connected in series between the input signal electrode and the output signal electrode;
• and
• a second surface acoustic wave resonator including:
• a plurality of signal-side terminals having a plurality of comb electrodes and connected to a midpoint between the input signal electrode and the first surface acoustic wave resonator, a midpoint between the output signal electrode and the first surface acoustic wave resonator, and a midpoint between adjacent ones of the first surface acoustic wave resonators, and
• a ground-side common terminal having a plurality of comb electrodes to form interdigital transducers in cooperation with the comb electrodes of the plurality of signal-side common terminals and connected to a grounding electrode.

A branching filter comprising:

• at least two surface acoustic wave devices having mutually different band center frequencies, and at least one of the surface acoustic wave devices comprising:
• an input signal electrode and an output signal electrode to and from which an electric signal is inputted or outputted;
• a first surface acoustic wave resonator connected between the input signal electrode and the output signal electrode;
• and
• a second surface acoustic wave resonator including:
• a plurality of signal-side terminals having a plurality of comb electrodes and connected to a midpoint between the input signal electrode and the third surface acoustic wave resonator and a midpoint between the output signal electrode and the third surface acoustic wave resonator, and
• a ground-side common terminal having a plurality of comb electrodes to form interdigital transducers by the comb electrodes and the comb electrodes of the plurality of signal-side common terminals and connected to a grounding electrode.

A branching filter comprising:

• at least two surface acoustic wave devices having mutually different band center frequencies, and at least one of the surface acoustic wave devices comprising:
• an input signal electrode and an output signal electrode to and from which an electric signal is inputted or outputted;
• a plurality of first surface acoustic wave resonators connected in series between the input signal electrode and the output signal electrode;
• and
• a second surface acoustic wave resonator including:
• a plurality of signal-side terminals having a plurality of comb electrodes and connected to a midpoint between the input signal electrode and the third surface acoustic wave resonator, a midpoint between the output signal electrode and the third surface acoustic wave resonator, and a midpoint between adjacent ones of the first surface acoustic wave resonators, and
• a ground-side common terminal having a plurality of comb electrodes to form interdigital transducers by the comb electrodes and the comb electrodes of the plurality of signal-side common terminals and connected to a grounding electrode.