Abstract: In an electron tube including vibration absorbers for linear members such as filaments, a vibration absorbing means that is made of a vibration absorber with a large vibration absorption effect, has a simple configuration, and is attachable easily to filaments is provided. The vibration absorbing means is formed of a holder 231, a vibration absorber 241, and a getter shielding member 251. These three members are attached to a shielding electrode S overlying the front substrate 111 to dispose the vibration absorber 241 between the holder 231 and getter shielding member 251. The vibration absorber 241 is mounted to slide or rotate between the holder 231 and the getter shielding member 251. The vibration absorber 241 has an aperture 2413 in which the filament is engaged. The bottom (apex) of the aperture 2413 is formed eccentrically. The vibration absorber 241 is in line contact with the shielding electrode S, as shown in FIG. 3(c).

Abstract: In a parking lot management system, which is applied to a parking lot having a plurality of parking spaces, information about parking is wirelessly communicated between a plurality of wireless LAN base stations connected to an interface part and then connected to the Internet, and a plurality of parking condition detection devices or a wireless LAN mobile station installed in a mobile object. The information is managed by a server via an IP network so that the parking lot management system can provide the information for a user who is in the parking lot.

Abstract: A high-performance SAW filter is to be provided which has lower insertion loss in a pass band and high attenuation in an attenuation band on the low frequency side of the pass band. In a SAW filter with attenuation poles configured of a two-port circuit for filtering for forming a ladder type SAW filter using a SAW resonator and a two-port circuit for impedance formed of an impedance serially connected, the impedance of the two-port circuit for impedance is configured so as to form an attenuation band of a predetermined width having a sufficient attenuation characteristic on the low frequency side of a pass band.

Abstract: In an electron tube including vibration absorbers for linear members such as filaments, a vibration absorbing means that is made of a vibration absorber with a large vibration absorption effect, has a simple configuration, and is attachable easily to filaments is provided. The vibration absorbing means is formed of a holder 231, a vibration absorber 241, and a getter shielding member 251. These three members are attached to a shielding electrode S overlying the front substrate 111 to dispose the vibration absorber 241 between the holder 231 and getter shielding member 251. The vibration absorber 241 is mounted to slide or rotate between the holder 231 and the getter shielding member 251. The vibration absorber 241 has an aperture 2413 in which the filament is engaged. The bottom (apex) of the aperture 2413 is formed eccentrically. The vibration absorber 241 is in line contact with the shielding electrode S, as shown in FIG. 3(c).

Abstract: In a parking lot management system, which is applied to a parking lot having a plurality of parking spaces, information about parking is wirelessly communicated between a plurality of wireless LAN base stations connected to an interface part and then connected to the Internet, and a plurality of parking condition detection devices or a wireless LAN mobile station installed in a mobile object. The information is managed by a server via an IP network so that the parking lot management system can provide the information for a user who is in the parking lot.

Abstract: A high-performance SAW filter is to be provided which has lower insertion loss in a pass band and high attenuation in an attenuation band on the low frequency side of the pass band. In a SAW filter with attenuation poles configured of a two-port circuit for filtering for forming a ladder type SAW filter using a SAW resonator and a two-port circuit for impedance formed of an impedance serially connected, the impedance of the two-port circuit for impedance is configured so as to form an attenuation band of a predetermined width having a sufficient attenuation characteristic on the low frequency side of a pass band.

Abstract: A surface acoustic wave duplexer includes a piezoelectric substrate; a transmitting filter formed on the piezoelectric substrate; a receiving filter formed on the piezoelectric substrate; a transmitting (Tx) branching line formed on the piezoelectric substrate; and a receiving (Rx) branching line formed on the piezoelectric substrate.

Abstract: A duplexer has four surface-acoustic-wave resonators, forming two filters, integrated on a piezoelectric substrate. The surface-acoustic-wave resonators are laid out so that the two resonators with intermediate resonance frequencies are separated from each other by one or both of the resonators with the highest and lowest resonance frequencies, thereby improving isolation between the two filters. In one configuration the two filters are ladder filters, and the resonators are laid out in a row in which the series-arm resonator of the receiving filter is followed by the shunt-arm resonator of the receiving filter, then the series-arm resonator of the transmitting filter, then the shunt-arm resonator of the transmitting filter. The two filters may also be separated by a groove in the substrate.

Abstract: 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.

Abstract: A surface acoustic wave duplexer includes a piezoelectric substrate; a transmitting filter formed on the piezoelectric substrate; a receiving filter formed on the piezoelectric substrate; a transmitting (Tx) branching line formed on the piezoelectric substrate; and a receiving (Rx) branching line formed on the piezoelectric substrate.

Abstract: 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.

Abstract: In a surface acoustic wave filter having tooth comb-type cross electrodes provided over a plurality of levels, connection patterns to connect and ground all the patterns on a chip via dicing lines are provided with at least one of the connection patterns provided between reflectors. Thus, all the electrode patterns are grounded even in a surface acoustic wave filter with the tooth comb-type cross electrodes provided over a plurality of levels, and, as a result, electrostatic breakdown due to discharge can be prevented.

Abstract: A duplexer has four surface-acoustic-wave resonators, forming two filters, integrated on a piezoelectric substrate. The surface-acoustic-wave resonators are laid out so that the two resonators with intermediate resonance frequencies are separated from each other by one or both of the resonators with the highest and lowest resonance frequencies, thereby improving isolation between the two filters. In one configuration the two filters are ladder filters, and the resonators are laid out in a row in which the series-arm resonator of the receiving filter is followed by the shunt-arm resonator of the receiving filter, then the series-arm resonator of the transmitting filter, then the shunt-arm resonator of the transmitting filter. The two filters may also be separated by a groove in the substrate.

Abstract: In a differential surface acoustic wave resonator, when an unbalanced electric signal is inputted between an input terminal 301 and an output terminal connected to a ground potential, this electric signal is inputted to two-terminal-pair surface acoustic wave resonators 351 and 352. The electric signal inputted to the two-terminal-pair surface acoustic wave resonator 351 is converted into a surface acoustic wave, and thereafter it is again converted into an electric signal to be outputted to a two-terminal-pair surface acoustic wave resonator 353. The electric signal inputted to the two-terminal-pair surface acoustic wave resonator 353 is converted into a surface acoustic wave, and thereafter it is again converted into an electric signal to be outputted from an output terminal 302 of the differential surface acoustic wave filter as a balanced signal.

Abstract: 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.

Abstract: Disclosed is a surface acoustic wave filter having a first serial-arm SAW resonator coupled to an input terminal and a first dual-mode SAW resonator coupled between the first serial-arm SAW resonator and an output terminal, wherein the first dual-mode SAW resonator includes first to third comb-shaped interdigital transducers, the second comb-shaped interdigital transducer is arranged between the first and third comb-shaped interdigital transducers and also coupled between the first serial-arm SAW resonator and the ground potential, and each of the first and third comb-shaped interdigital transducers is coupled between the ground potential and the output terminal. Also disclosed is a branching filter utilizing the surface acoustic wave filter.

Abstract: 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.

Abstract: A surface-acoustic-wave filter couples a two-port surface-acoustic-wave resonator filter circuit coupled in parallel or in series with a two-port impedance circuit. The two-port impedance circuit has an impedance that creates a pole of attenuation, by making the open-circuit impedance of the surface-acoustic-wave filter equal to the short-circuit impedance. High attenuation over a wide range of stopband frequencies is obtained in this way, combined with steep roll-off between the passband and stopband.

Abstract: A compact, high performance strip line filter which may be made thinner than a dielectric filter having comparable performance characteristics. The strip line filter includes a rectangular box-shaped, dielectric block having parallel grooves, formed in a front face with a predetermined spacing therebetween, the grooves extending from a top face to a bottom face of the block. A thin film outer conductive layer covers the side faces, the back face, and the bottom face. Resonator conductors, each formed of a thin film of conductive material, cover the respective surfaces of the grooves and are connected to the outer conductor. According to a further aspect, a substrate, with capacitor formed thereon, opposes a face of the dielectric block to provide capacitive coupling. The capacitors may be arranged to provide attenuation poles at finite frequencies. In accordance with another aspect, such strip line filters are used as the transmitting and receiving filters of a duplexer filter.

Abstract: A surface-acoustic-wave filter couples a two-port surface-acoustic-wave resonator filter circuit coupled in parallel or in series with a two-port impedance circuit. The two-port impedance circuit has an impedance that creates a pole of attenuation, by making the open-circuit impedance of the surface-acoustic-wave filter equal to the short-circuit impedance. High attenuation over a wide range of stopband frequencies is obtained in this way, combined with steep roll-off between the passband and stopband.