MULTIPLEXER, RADIO-FREQUENCY FRONT-END CIRCUIT, COMMUNICATION APPARATUS, AND ELASTIC WAVE FILTER

• Main Author: NOSAKA, Koji
• Format: Patent
• Language: English
• Published: 14.01.2021
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS; TRANSMISSION

A multiplexer includes a first filter located between a common terminal and a first terminal to pass a signal in a first passband, and a second filter located between the common terminal and a second terminal to pass a signal in a second passband. A first series arm circuit included in the first filter includes a first series arm resonator and a second series arm resonator. The first series arm circuit is connected to the common terminal not through a circuit including an elastic wave resonator and a connecting point of the circuit. The first series arm circuit has a first antiresonance frequency and a second antiresonance frequency higher than the first antiresonance frequency. The second antiresonance frequency is higher than a higher edge of the first passband. The first antiresonance frequency is at or lower than a higher edge of the second passband.