Multiplexer, radio-frequency module, and communication apparatus

A multiplexer comprising:

• a first filter connected to a common terminal and having a first pass band including a first band sized to pass a signal;
• and
• a second filter connected to the common terminal and having a second pass band including a second band which is sized to pass another signal,
• wherein the first filter includes
• a first series arm resonator disposed on a first series arm path which connects the common terminal and a first radio-frequency input terminal that receives a first sending signal of the first band, and
• a first parallel arm resonator disposed on a first parallel arm path which connects the first series arm path and a ground,
• wherein each of the first series arm resonator and the first parallel arm resonator includes
• a first support substrate,
• a first bottom electrode disposed above the first support substrate,
• a first top electrode disposed above the first bottom electrode, and
• a first piezoelectric layer disposed between the first bottom electrode and the first top electrode,
• wherein at least one of resonators forming the first series arm resonator and the first parallel arm resonator is constituted by a plurality of series-divided resonators connected in series with each other,
• wherein the second filter includes
• a second series arm resonator disposed on a second series arm path which connects the common terminal and a second radio-frequency input terminal that receives a second sending signal of the second band, and
• a plurality of second parallel arm resonators disposed on individual second parallel arm paths, each of the second parallel arm paths connecting the second series arm path and a ground,
• wherein each of the second series arm resonator and the plurality of second parallel arm resonators includes
• a second support substrate,
• a second bottom electrode disposed above the second support substrate,
• a second top electrode disposed above the second bottom electrode, and
• a second piezoelectric layer disposed between the second bottom electrode and the second top electrode, and
• wherein, two second parallel arm resonators of the plurality of second parallel arm resonators, one second parallel arm resonator being directly connected to one end of the second series arm resonator, the other second parallel arm resonator being directly connected to the other end of the second series arm resonator, the second top electrodes or the second bottom electrodes of the two second parallel arm resonators are formed by one electrode.