Multiplexer, high-frequency front-end circuit, and communication device

A multiplexer comprising:

• a common terminal;
• a first terminal;
• a second terminal;
• a first filter disposed on a first path connecting the common terminal and the first terminal to each other and that includes a plurality of elastic wave resonators;
• and
• a second filter disposed on a second path connecting the common terminal and the second terminal to each other and that has a pass band higher in frequency than a pass band of the first filter;
• wherein
• the plurality of elastic wave resonators include:
• one or more serial resonators that are disposed on the first path;
• and
• two or more parallel resonators each of which is disposed on a path connecting a node on the first path and a ground to each other;
• the two or more parallel resonators include a first parallel resonator located on a side of the common terminal and a parallel resonator located on a side of the first terminal when seen from a first serial resonator that is one of the one or more serial resonators and that is closer to the common terminal than a remainder of the one or more serial resonators;
• each of the plurality of elastic wave resonators includes a substrate having piezoelectricity, an interdigital transducer (IDT) electrode including a pair of comb-shaped electrodes that are provided on the substrate, and a dielectric layer provided on the substrate so as to cover the IDT electrode;
• and
• the dielectric layer of the first parallel resonator and the dielectric layer of the first serial resonator each have a thickness smaller than a thickness of the dielectric layer or layers of a remainder of the plurality of elastic wave resonators.