Elastic wave resonator, band pass filter, and duplexer

An elastic wave resonator comprising:

• a piezoelectric substrate;
• a first interdigital transducer electrode and a second interdigital transducer electrode that are arranged on the piezoelectric substrate in an elastic-wave propagation direction with a gap located between the first interdigital transducer electrode and the second interdigital transducer electrode;
• a third interdigital transducer electrode and a fourth interdigital transducer electrode that are arranged on the piezoelectric substrate in the elastic-wave propagation direction with a gap located between the third interdigital transducer electrode and the fourth interdigital transducer electrode, the third interdigital transducer electrode and the fourth interdigital transducer electrode respectively facing the first interdigital transducer electrode and the second interdigital transducer electrode in a direction orthogonal or substantially orthogonal to the elastic-wave propagation direction;
• a first reflector disposed between the first interdigital transducer electrode and the second interdigital transducer electrode and between the third interdigital transducer electrode and the fourth interdigital transducer electrode, the first reflector being shared by the first interdigital transducer electrode to the fourth interdigital transducer electrode;
• a second reflector shared by the first interdigital transducer electrode and the third interdigital transducer electrode;
• and
• a third reflector shared by the second interdigital transducer electrode and the fourth interdigital transducer electrode;
• wherein
• the second reflector and the first reflector sandwich the first interdigital transducer electrode and the third interdigital transducer electrode in the elastic-wave propagation direction;
• the third reflector and the first reflector sandwich the second interdigital transducer electrode and the fourth interdigital transducer electrode in the elastic-wave propagation direction;
• the first interdigital transducer electrode, the second interdigital transducer electrode, the third interdigital transducer electrode, and the fourth interdigital transducer electrode respectively include a first busbar, a second busbar, a third busbar, and a fourth busbar, the first interdigital transducer electrode and the third interdigital transducer electrode share a first common busbar, and the second interdigital transducer electrode and the fourth interdigital transducer electrode share a second common busbar;
• and
• the first busbar, the second busbar, the third busbar, and the fourth busbar are electrically connected to each other.