Multiplexer

A multiplexer comprising:

• a first terminal;
• a second terminal;
• a third terminal;
• a first filter that is connected between the first terminal and the second terminal, includes a first capacitor, a first inductor, and one or more first acoustic wave resonators, and has a first passband;
• a second filter that is connected between the first terminal and the third terminal, includes a second capacitor, a second inductor, and one or more second acoustic wave resonators, and has a second passband higher than the first passband, the second passband not overlapping with the first passband;
• a substrate that has a surface on which a film is directly located, at least one first acoustic wave resonator of the one or more first acoustic wave resonators and at least one second acoustic wave resonator of the one or more second acoustic wave resonators including the film, the at least one first acoustic wave resonator being shunt-connected between the first terminal and the second terminal;
• the at least one second acoustic wave resonator being shunt-connected between the first terminal and the third terminal;
• a resonant frequency of the at least one first acoustic wave resonator and a resonant frequency of the at least one second acoustic wave resonator being located between the first passband and the second passband;
• and
• a metal structure that is located on the surface, and is located between the at least one first acoustic wave resonator and the at least one second acoustic wave resonator,
• wherein
• the resonant frequency of the at least one first acoustic wave resonator is formed by the at least one first acoustic wave resonator without a separate inductor or capacitor and the resonant frequency of the at least one second acoustic wave resonator is formed by the at least one second acoustic wave resonator without a separate inductor or capacitor, and
• no capacitor is connected in parallel with the at least one first acoustic wave resonator between a first end of the at least one first acoustic wave resonator and a second end of the at least one first acoustic wave resonator and no capacitor is connected in parallel with the at least one second acoustic wave resonator between a first end of the at least one second acoustic wave resonator and a second end of the at least one second acoustic wave resonator.