Multiplexer

A multiplexer comprising:

• a common terminal;
• and
• a plurality of filters connected to the common terminal, each of the plurality of filters including a plurality of resonators;
• wherein
• the plurality of filters include:
• a first transmission filter having a pass band including a first transmission band;
• a second transmission filter having a pass band including a second transmission band different from the first transmission band;
• and
• a first reception filter having a pass band including a first reception band;
• wherein
• a center frequency of the first reception band is between a center frequency of the first transmission band and a center frequency of the second transmission band;
• in a case where an electric equivalent circuit of a specific resonator among the plurality of resonators in each of the plurality of filters is represented by using a parallel circuit including a series circuit of an equivalent resistance, an equivalent inductor, and an equivalent capacitance, and a damping capacitance, and a current flowing in the series circuit is defined as an acoustic path current;
• under conditions that a phase of an acoustic path current of the first transmission filter at a side of the common terminal at a frequency within the first transmission band is represented as θ1Tx, a phase of an acoustic path current of the first transmission filter at the side of the common terminal at a frequency within the second transmission band is represented as θ2Tx, a phase of an acoustic path current of the first reception filter at the side of the common terminal at a frequency within the first transmission band is represented as θ1Rx, and a phase of an acoustic path current of the first reception filter at the side of the common terminal at a frequency within the second transmission band is represented as θ2Rx;
• the multiplexer satisfies a first condition or a second condition;
• and
• the first condition is a condition that
• |(2·θ1Tx−θ2Tx)−(2·θ1Rx−θ2Rx)|=180°±90°;
• and
• the second condition is a condition that
• |(2·θ2Tx−θ1Tx)−(2·θ2Rx−θ1Rx)|=180°±90°.