A power transmitting antenna 105, which is arranged on the ground, and a power receiving antenna 107, which is arranged at the bottom of the vehicle 101, set up resonances at substantially the same resonant frequency and produce magnetic coupling between them. When the power receiving antenna 107 enters the zone in which the power transmitting antenna 105 is located, power is transmitted to the vehicle. By setting H, which is the distance between the power transmitting and receiving antennas that face each other, so that H satisfies 0.11xW1 ≦ H ≦ 0.26 x W1 with respect to the width W1 of the power transmitting antenna, the transmission characteristic can be stabilized.

Electric power supply system for vehicle

A surface acoustic wave device includes a surface acoustic wave element and a sealing member for sealing the surface acoustic wave element. The surface acoustic wave element has a piezoelectric substrate and an electrode provided on the piezoelectric substrate. The sealing ember is made of a resin or glass. The electrode has an electrode layer made of Al or an Al alloy and includes crystals having a twin structure.

Surface acoustic wave device

A duplexer has an asymmetrical antenna port and a symmetrical reception output, and therefore can be interconnected (without any intermediate stages) to an amplifier with a differential input. A reception bandpass filter is arranged in the reception path of the duplexer. The reception bandpass filter can have the functionality of a balun. The transmission input of the duplexer can be designed symmetrically, in which case a transmission bandpass filter arranged in the transmission path should be designed symmetrically on the input side. The impedance of the antenna port of the duplexer can differ from the impedance of the reception output or the transmission input. No intermediate stages (such as a balun or—in cases of impedances that differ between the duplexer and its corresponding amplifier—an impedance transformer) are required between the duplexer and the amplifier that is interconnected (whether before or after) in the transmission or reception path.

Duplexer with extended functionality

An acoustic wave device includes a ladder-type filter in which resonators are connected in a ladder configuration. In the acoustic wave device, series-connected resonators are connected in a parallel line in the ladder-type filter, and the resonators connected in the parallel line have mutually different resonance frequencies.

Acoustic wave filter, duplexer, communication module, and communication apparatus

Acoustic resonators such as surface acoustic wave (SAW) devices and thin film bulk acoustic resonators (FBAR) can be configured to produce a band reject filter. Such a filter overcomes the insertion loss and power handling limitations of conventional band pass configurations and as such can be used in power amplifier and duplexer applications.

Band reject filters

PROBLEM TO BE SOLVED: To inhibit degradation and destruction of series arm resonators of a surface acoustic wave filter by reducing the currents flowing through the series arm resonators to lower the applied power SOLUTION: A surface acoustic wave filter to be disclosed comprises a plurality of series arm resonators in which a first series arm resonator connected to an input terminal, a second series arm resonator connected to an output terminal, and a third arm resonator connected between the first and second series arm resonators, are respectively connected in series, a plurality of parallel arm resonators including a first parallel arm resonator connected in parallel to the first series arm resonator and a second arm resonator connected in parallel to the third series arm resonator, and a ground terminal to which the first and second parallel arm resonators are connected, wherein the resonance frequency of the third series arm resonator is different from the resonance frequency of the first series arm resonator and that of the second series arm resonator COPYRIGHT: (C)2007,JPO&INPIT

Surface acoustic wave filter

A polar SAW (Surface Acoustic Wave) filter includes a band-pass ladder type SAW filter having a SAW resonator. A two-terminal pair circuit is serially connected to the band-pass ladder type SAW filter and includes a plurality of inductors. The polar SAW filter has attenuation poles in each of the higher-frequency and lower-frequency attenuation ranges of a pass band.

Saw filter with an attenuation pole including a band-pass ladder type of saw filter having a saw resonator

An antenna duplexer has a first filter and a second filter coupled to respective signal terminals and to a common node. The common node is coupled to an antenna terminal. The first filter has a higher-frequency passband than the second filter. A transmission-line circuit, inserted between the first filter and the common node, increases the impedance of the first filter in its lower stopband. The transmission-line circuit includes an internal node, a first transmission line coupling the internal node to the common node, a second transmission line coupling the internal node to the first filter, and a grounding circuit such as a capacitor coupling the internal node to ground. The grounding circuit further enhances the lower stopband impedance of the first filter.

Antenna duplexer with divided and grounded transmission line

A branching filter package has a SAW filter chip housing area which houses a piezo electric base, on which a transmitting SAW filter and a receiving SAW filter having a different frequency passing band with each other, are formed, and an impedance matching circuit and a branching circuit for the transmitting SAW filter and the receiving SAW filter.

Branching filter package

A branching filter comprising a SAW resonator. The branching filter comprises a transmission SAW filter linked between an antenna terminal and a transmission terminal; a receiving SAW filter with different bandpass characteristics from the transmission SAW filter linked between the antenna terminal and the transmission terminal; a composite circuit that combines a frequency adjusting LC circuit linked between the antenna terminal and the transmission and receiving SAW filters with a branching filter circuit; and the branching filter circuit being structured to have a serial arm SAW resonator.

Yoshiaki Fujita

Papers

Surface acoustic wave filter

Saw filter with an attenuation pole including a band-pass ladder type of saw filter having a saw resonator

Antenna duplexer with divided and grounded transmission line

Branching filter package

Branching filter with a composite circuit of an LC circuit and a serial arm saw resonator