A SAW resonator comprises two reflectors and a transducer arranged between the reflectors. A resonant space between the transducer and a respective reflector is set large enough to enable occurrence of main resonance and at least one further resonance of comparable admittance. Thus, a multiple resonant resonator is achieved that can be used as a parallel resonator in a filter circuit with a DMS track for example to improve attenuation in a stop band.

A SAW resonator comprises two reflectors and a transducer arranged between the reflectors. A resonant space between the transducer and a respective reflector is set large enough to enable occurrence of main resonance and at least one further resonance of comparable admittance. Thus, a multiple resonant resonator is achieved that can be used as a parallel resonator in a filter circuit with a DMS track for example to improve attenuation in a stop band.

A phase shifter module includes a base material, a common terminal, and individual terminals, the common terminal and the individual terminals being provided at the base material. Inside the base material, phase shifters that are connected between the individual terminals and the common terminal, respectively, are provided. The phase shifters each include a primary coil and a secondary coil that is coupled to the primary coil by magnetic field coupling and define a transformer phase shifter. With this configuration, a phase shifter module for use with SAW filters while reducing or preventing interference among the SAW filters, a multiplexer/demultiplexer that includes the phase shifter module, and a communication apparatus that includes the phase shifter module, are obtained.

A multiplexer includes a common terminal, a Band66 transmission-side filter, a Band30 transmission-side filter, and an inductance element. The Band66 transmission-side filter includes series arm resonators and parallel arm resonators. The frequency of spurious waves generated by the Band66 transmission-side filter is included in a pass band of the Band30 transmission-side filter. A transmission output terminal is connected to a common terminal with the inductance element interposed therebetween and is directly connected to one parallel arm resonator. The one parallel arm resonator has a largest capacitance, among the parallel arm resonators.

An elastic wave apparatus includes first and second bandpass filters and the first bandpass filter is a ladder elastic wave filter. The mounting substrate includes an inductor which is connected between at least one of parallel arm resonators and a ground potential, a signal wiring at a hot side, which is connected to the first bandpass filter, and a ground wiring. When the mounting substrate is viewed from a side of a surface on which the elastic wave filter chip is mounted, a portion of the inductor overlaps with a portion of the signal wiring and a slit defining a wiring missing portion in which the ground wiring is absent in the ground wiring is provided in the overlapped portion.

A filter module includes an antenna connection terminal, filter elements, and inductors. The filter elements are connected to an antenna connection terminal. A first inductor is connected between the antenna connection terminal and the filter elements. A second inductor is connected between a transmission line, which connects the first inductor and the filter elements, and a ground reference potential. The filter elements are on an insulating multilayer substrate. The inductors include electrodes on the multilayer substrate. Inductor electrodes of the first inductor and central cavities of the inductor electrodes are at positions different from other electrodes inside the multilayer substrate.

A phase shifter module includes a base material, a common terminal, and individual terminals, the common terminal and the individual terminals being provided at the base material. Inside the base material, phase shifters that are connected between the individual terminals and the common terminal, respectively, are provided. The phase shifters each include a primary coil and a secondary coil that is coupled to the primary coil by magnetic field coupling and define a transformer phase shifter. With this configuration, a phase shifter module for use with SAW filters while reducing or preventing interference among the SAW filters, a multiplexer/demultiplexer that includes the phase shifter module, and a communication apparatus that includes the phase shifter module, are obtained.

A multiplexer includes a common terminal, a Band66 transmission-side filter, a Band30 transmission-side filter, and an inductance element. The Band66 transmission-side filter includes series arm resonators and parallel arm resonators. The frequency of spurious waves generated by the Band66 transmission-side filter is included in a pass band of the Band30 transmission-side filter. A transmission output terminal is connected to a common terminal with the inductance element interposed therebetween and is directly connected to one parallel arm resonator. The one parallel arm resonator has a largest capacitance, among the parallel arm resonators.

An elastic wave apparatus includes first and second bandpass filters and the first bandpass filter is a ladder elastic wave filter. The mounting substrate includes an inductor which is connected between at least one of parallel arm resonators and a ground potential, a signal wiring at a hot side, which is connected to the first bandpass filter, and a ground wiring. When the mounting substrate is viewed from a side of a surface on which the elastic wave filter chip is mounted, a portion of the inductor overlaps with a portion of the signal wiring and a slit defining a wiring missing portion in which the ground wiring is absent in the ground wiring is provided in the overlapped portion.