Abstract: An inter-digital transducer has a piezoelectric substrate; and an IDT (inter-digital transducer) electrode having a pair of upper bus bar electrode and lower bus bar electrode placed facing each other on the piezoelectric substrate and a plurality of electrode fingers placed on the piezoelectric substrate each being led out from either the upper bus bar electrode or the lower bus bar electrode toward the other bus bar electrode, wherein the IDT electrode is constructed of a plurality of divisional IDT electrodes and connected to a balanced type terminal.

Abstract: A small in-band-flat-group-delay type dielectric filter having low-loss characteristics with a small amplitude deviation and uniform-group-delay frequency characteristics is obtained, which enables broad-band characteristics to be obtained easily. The in-band-flat-group-delay type dielectric filter includes a plurality of dielectric coaxial resonators, a coupling circuit comprising a combination of reactive elements, with which the dielectric coaxial resonators are coupled to one another, and input/output terminals connected to ends of the coupling circuit. The dielectric coaxial resonators coupled to the input/output terminals are allowed to have a different characteristic impedance from that of the inter-stage dielectric coaxial resonators.

Abstract: A mulitlayer ceramic device improves device functionality, reduces overall device size and profile, makes manufacturing easier, and improves reliability. A first ceramic layer 1 has a first multilayer circuit pattern 2 electrically connected through via holes 3. A second ceramic layer 2 also has a second multilayer circuit pattern 2 electrically connected through via holes 3. A thermosetting resin sheet 17 is disposed between the first and second ceramic layers. The thermosetting resin sheet has through holes filled with a conductive paste for electrically connecting one of multiple circuit pattern layers in the first ceramic layer with one of multiple circuit pattern layers in the second ceramic layer.

Abstract: An antenna duplexer has a receiving filter having a surface acoustic wave device; a transmitting filter having a dielectric resonator; and a matching circuit for matching the receiving filter and the transmitting filter with an antenna respectively, wherein the transmitting filter, receiving filter, and matching circuit are integrated with each other.

Abstract: A small in-band-flat-group-delay type dielectric filter having low-loss characteristics with a small amplitude deviation and uniform-group-delay frequency characteristics is obtained, which enables broad-band characteristics to be obtained easily. The in-band-flat-group-delay type dielectric filter includes a plurality of dielectric coaxial resonators, a coupling circuit comprising a combination of reactive elements, with which the dielectric coaxial resonators are coupled to one another, and input/output terminals connected to ends of the coupling circuit. The dielectric coaxial resonators coupled to the input/output terminals are allowed to have a different characteristic impedance from that of the inter-stage dielectric coaxial resonators.

Abstract: The present invention provides a small and low loss laminated bandpass filter by placing two strip lines 313 and 314 that form a resonator in a certain distance on the same layer and thereby electromagnetically coupling these strip lines.

Abstract: By using a method for manufacturing a dielectric laminated device, an opening is formed on a first dielectric sheet, a strip line and an input and output line including an input and output electrode are formed by burying electrode materials in said opening, the first dielectric sheet is laminated with the second and third dielectric sheets disposed above and below respectively to form a laminate, a first and second shield electrodes and a ground electrode are formed, an end of the strip line is connected to the ground electrode, the first shield electrode and the second shield electrode are mutually connected through the ground electrode, and the input and output electrode is exposed along the line direction of the strip line. By this constitution of the above dielectric laminated device, the mounting reliability of the dielectric laminated device can be further increased.

Abstract: A resonator having a dielectric element, a metal housing accommodating the dielectric element, and a low relative permittivity material holding the dielectric element so as to have a predetermined clearance generated between a dielectric element surface of the dielectric element to which a generated electric field is substantially orthogonal and a housing surface of the metal housing opposed to the dielectric element surface.

Abstract: A high-frequency filter device includes at least one filter to be connected to a high-frequency stage of a wireless apparatus. The filter includes a voltage-controlled variable frequency resonance element which is made of a resonance element and a voltage-controlled variable impedance element electrically connected to the resonance element. The high-frequency filter device includes a control section for controlling a voltage applied to the variable impedance element, and a signal monitoring section for outputting a control signal, with which the voltage is controlled, to the control section based on frequency data as to an oscillating frequency of a local oscillator of the wireless apparatus. The signal monitoring section controls a band frequency of the at least one filter based on the frequency data in such a manner that the band frequency is adaptively changed.

Abstract: A layered body of a SAW filter includes a surface dielectric layer having a surface layer electrode pattern formed thereon, and a first dielectric layer having a pair of electrode patterns and a first ground electrode pattern formed thereon. A pair of balanced output terminals of SAW filters of unbalanced input-balanced output are connected respectively to the pair of electrode patterns via the surface layer electrode pattern, and a part of the first ground electrode pattern is disposed between the pair of the electrode patterns.

Abstract: A dielectric filter including a plurality of resonators, and at least one transmissions line provided among said plurality of resonators. A band rejection characteristic is formed around a resonance frequency of said resonator, and a line length of said transmission line is shorter than ¼ of a wavelength corresponding to the resonance frequency of said resonator.

Abstract: A filter having an unbalanced terminal, a first stripline resonator of which one end is connected to the unbalanced terminal, a second stripline resonator placed to be electromagnetically coupled to the first stripline resonator, and balanced terminals and of which both ends are connected to the second stripline resonator, wherein the first stripline resonator and the second stripline resonator are connected by at least one impedance element, and the second stripline resonator is a ½ wavelength resonator substantially having ½ length of a wavelength of a resonance frequency.

Abstract: A high-frequency compound switch module of this invention has a first communication system comprising a switch unit for switching connection of a signal from an antenna to one of a transmission circuit and a reception circuit of the first communication system based on a signal from a control terminal, a filter provided on a first reception circuit side, for filtering out a first reception signal, and a first phase shift line provided between the filter and the switch unit, and a second communication system comprising a second phase shift line provided between the switch unit and the first phase shift line, and a branching filter provided in series to the second phase shift line for branching a signal from the second phase shift line into a second transmission signal and a second reception signal. The switch module is capable of performing at least a receiving process of the first communication system while performing transmission/reception with the second communication system.

Abstract: A surface acoustic wave filter has a piezoelectric substrate and at least two interdigital transducer electrodes on the piezoelectric substrate, wherein at least one of the interdigital transducer electrodes includes a unidirectional electrode and bidirectional electrode, and the length &lgr;d of a basic cell of the unidirectional electrode is longer than the length &lgr;s of a basic cell of the bidirectional electrode.

Abstract: In order to prevent filter characteristics from being deteriorated due to generation of a spurious pulse is unnecessary resonance at a high level in a passing band at the frequency in a microwave region used in a portable telephone system or the like, at least two types of dielectric resonators having different frequency characteristics in unnecessary harmonic modes except for a main mode near the passing band of a filter are arranged in spaces partitioned by partition walls in a shielding unit constituted by a metal case and a lid, so that a dielectric filter which can obtain preferable spurious suppressing characteristics.

Abstract: The invention provides a dielectric filter including a metal case having an opening in the upper part, a metal lid of closing the opening, a dielectric resonance element placed on the internal bottom face of the case through a support, a bolt made of dielectric material inserted in a position in the lid corresponding to the dielectric resonance element, and a metal plate placed at the end of the bolt substantially in parallel with the upper face of the dielectric resonance element, wherein the position of the bolt is adjusted to change the space between the dielectric resonance element and the plate, whereby the resonance frequency is controlled.

Abstract: To provide a strong input/output coupling while preventing a Q-value from deteriorating.

Abstract: Interdigital transducers (IDT electrodes), reflectors, etc., are formed on a piezoelectric substrate. An unbalanced input/output terminal is connected to a first input/output terminal. A first inductor is connected between a first terminal, which is one of the balanced input/output terminals, and a second terminal, which is the other of the balanced input/output terminals. Further, a second inductor is connected between the first terminal in the balanced input/output terminals and a second input/output terminal, and the second terminal in the balanced input/output terminals is connected to a third input/output terminal.

Abstract: A balanced high-frequency device is constituted by a balanced device and a phase circuit. The input side of the balanced device is connected to an input terminal IN serving as an unbalanced input/output terminal and the output side of it is connected to output terminals OUT1 and OUT2 serving as balanced input/output terminals. Moreover, the phase circuit is connected between the output terminals.

Abstract: A 3-frequency branching circuit in the past could not be used for a system wherein a TDMA method such as GSM and DCS and a W-CDMA method such as UMTS are mixed. The 3-frequency branching circuit equipped with branching means having first and second internal terminals 21 and 22, an antenna terminal 20 of connecting to an antenna, a low-pass filter connected between the first internal terminal 21 and the antenna terminal 20, and a high-pass filter connected between the second internal terminal 22 and the antenna terminal 20, a switching circuit 1 of switching between GSMTX and GSMRX, a switching circuit 2 of switching between DCS TX, DCS RX and a third internal terminal 23, and a duplexer connected to the third internal terminal 23.