Duplexer and communication module

A duplexer, comprising,

• an antenna terminal which receives signal waves and disturbance waves,
• a transmission filter which is connected to the antenna terminal,
• a reception filter which is connected to the antenna terminal, and receives a portion of the signal waves, and has a passband of a frequency range higher than a passband of the transmission filter, and
• a disturbance wave resonator which is connected to the antenna terminal and to a ground and positioned closer to a side of the antenna terminal than the transmission filter and the reception filter,
• wherein a resonance frequency of the disturbance wave resonator is within a disturbance wave band which is a frequency range lower than the passband of the transmission filter and which includes a frequency range of the disturbance waves,
• wherein a antiresonance frequency of the disturbance wave resonator is deviated relative to a frequency at the center of the passband of the transmission filter by an extent of 10% or more of a bandwidth of the passband of the transmission filter, and
• wherein the antiresonance frequency of the disturbance wave resonator is higher than the passband of the transmission filter.

A duplexer, comprising:

• an antenna terminal which receives signal waves and disturbance waves,
• a transmission filter which is connected to the antenna terminal,
• a reception filter which is connected to the antenna terminal, and receives a portion of the signal waves, and has a passband of a frequency range higher than a passband of the transmission filter, and
• a disturbance wave resonator which is connected to the antenna terminal and to a ground and positioned closer to a side of the antenna terminal than the transmission filter and the reception filter,
• wherein a resonance frequency of the disturbance wave resonator is within a disturbance wave band which is a frequency range lower than the passband of the transmission filter and which includes a frequency range of the disturbance waves,
• wherein:
• the disturbance wave resonator comprises
• an antenna side comb-shaped electrode which is provided on a piezoelectric substrate and is connected to the antenna terminal, and
• a ground side comb-shaped electrode which is provided on the piezoelectric substrate, is connected to the ground, and is meshed with the antenna side comb-shaped electrode,
• wherein the transmission filter is a ladder type filter having serial resonators and parallel resonators,
• the serial resonator has
• an input side comb-shaped electrode which is provided on the piezoelectric substrate and to which the transmission signal is input and
• an output side comb-shaped electrode which is provided on the piezoelectric substrate, is connected to the antenna terminal, and is meshed with the input side comb-shaped electrode, and
• a direction from the input side comb-shaped electrode to the output side comb-shaped electrode in the serial resonator which is provided in the transmission filter and closest to the antenna terminal and a direction from the antenna side comb-shaped electrode to the ground side comb-shaped electrode are directions different from each other.

A duplexer, comprising:

• an antenna terminal which receives signal waves and disturbance waves,
• a transmission filter which is connected to the antenna terminal,
• a reception filter which is connected to the antenna terminal, and receives a portion of the signal waves, and has a passband of a frequency range higher than a passband of the transmission filter, and
• a disturbance wave resonator which is connected to the antenna terminal and to a ground and positioned closer to a side of the antenna terminal than the transmission filter and the reception filter,
• wherein a resonance frequency of the disturbance wave resonator is within a disturbance wave band which is a frequency range lower than the passband of the transmission filter and which includes a frequency range of the disturbance waves,
• wherein:
• the disturbance wave resonator comprises
• an antenna side comb-shaped electrode which is provided on a piezoelectric substrate and is connected to the antenna terminal, and
• a ground side comb-shaped electrode which is provided on the piezoelectric substrate, is connected to the ground, and is meshed with the antenna side comb-shaped electrode,
• wherein the transmission filter is a ladder type filter having serial resonators and parallel resonators,
• the disturbance wave resonator has
• a first capacitance electrode which is provided on the piezoelectric substrate and is connected to the antenna side comb-shaped electrode and
• a second capacitance electrode which is provided on the piezoelectric substrate, is connected to the ground side comb-shaped electrode, and faces the first capacitance electrode, and
• a direction from the antenna side comb-shaped electrode to the ground side comb-shaped electrode and a direction from the first capacitance electrode to the second capacitance electrode are directions different from each other.