Abstract: A high frequency composite switch module for a mobile communication device, wherein high frequency circuits such as a power amplifier, a circuit functioning as a transmitter/receiver switching circuit, a surface acoustic wave (SAW) filter for reception, and the like are modularized into one unit. A transmitter circuit includes a transmitter side impedance converter comprising an impedance matching circuit and an impedance converter circuit, a power amplifier and a power supply unit. A receiver circuit includes a receiver-side impedance converter comprising a phase shifting circuit and a SAW filter. The power amplifier and the impedance converter circuit are integrated into one IC chip. At least one of the matching circuit, the power supply unit and the phase shifting circuit is formed inside a multilayer board comprised of a conductor layer and a dielectric layer. The IC chip and the SAW filter are also mounted on the multilayer board.

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 high-frequency hybrid switch module arranged applicable to at least two different communications systems includes two low pass filters (LPFs), two phase shifters, a field effect transistor (FET) switch including FETs, and two SAW filters. The FETs and the SAW filters are mounted on a layered assembly including the LPFs and an electrode pattern of the phase shifters. The module can have a small overall size, a low cost, and a small loss, while being protected from static electricity. The module requires small number of low-noise amplifiers at a signal receiving side.

Abstract: An antenna device which includes the first antenna element having one end open and the other end connected to a power feeder, and the second antenna element. having both ends open. The second antenna element is disposed on the outer peripheral surface of the first antenna element in insulated state. The other end of the first antenna element is connected to the power feeder through the first ring-shaped conductor.

Abstract: The present invention relates to an antenna mainly used in a cellular phone or the like and to a communication terminal using it. It is hence an object thereof to realize an antenna having a high radiation efficiency, a wide adjustable range of the impedance of the antenna, and a capability of matching with an RF circuit by the structure itself without using a matching circuit. The number of structural parameters for adjusting the impedance of the antenna increases. To achieve the object, the antenna in the communication terminal of the present invention has a radiation element wound spirally around an insulating core in the winding direction inverted at an arbitrary position. The antenna is hence capable of adjusting the impedance, and as a result, the number of structural parameters of the antenna increases, and the adjustable range of the impedance of the antenna is expanded.

Abstract: A low pass filter (LPF) can realizes a sophisticated transmission filter usable in a dual-band application. The transmission filter features a compact size, a low cost, a lower insertion loss, and an excellent harmonics-suppression characteristic. In the LPF, a high pass filter (HPF) section working in a high frequency band or a band pass filter (BPF) section, is coupled with a first LPF section in parallel between an input terminal and an output terminal. The HPF section or the BPF section includes a switch circuit formed of one diode that switches the pass band thereof to a rejection band. In one case, a signal passing through the HPF section or the BPF section is input to the input terminal. In the other case, a signal passing thorough the first LPF is input to the input terminal.

Abstract: A small radio-frequency hybrid switch module is provided for switching between transmitted signals and received signals in plural frequency bands. This module includes: a laminated body including a dielectric layer; a diplexer; a switching circuit; a low pass filter (LPF); a conductive pattern provided on the dielectric layer for forming at least one of the diplexer, the switching circuit and the LPF; a surface acoustic wave (SAW) filter mounted on the laminated body; a cover provided on the SAW filter for forming a cavity which allows surface acoustic wave vibration and for hermetically sealing the cavity; and a semiconductor switching device mounted on the laminated body for forming a part of the switching circuit.

Abstract: A small-size multi-frequency antenna duplexer using surface acoustic wave filters and capable of dealing with a plurality of frequencies. Each antenna duplexer comprises two surface acoustic wave (SAW) filters used for transmission and reception, respectively, and having different frequency pass bands; a phase substrate; and a package housing the foregoing filters and substrate. The pass bands of the antenna duplexers are different from one another. This multi-frequency antenna duplexer comprises a plurality of antenna duplexers. A respective package (14) contains a transmitting surface acoustic wave filter (11a, 11b), a receiving surface acoustic wave filter (12a, 12b) and a phase substrate (13a, 13b). In this way, the size of multi-frequency antenna duplexer can be reduced.

Abstract: A small antenna, which is used in a mobile radio communication apparatus such as a portable telephone, operating in a broader frequency band a conventional antenna, operating corresponding to plural frequencies, and being disposed in a case is provided The radio communication apparatus including the antenna is also provided. The antenna includes a first conductive radiator having a planer shape, a second conductive radiator having a helical shape, and a planar feeding section that is disposed between the first conductive radiator and the ground plane, is isolated from them, and supplying power by electromagnetic coupling.

Abstract: A detector detects frequencies in two predetermined bands separately with respective predetermined coupling. The detector includes a first transmission line, and second and third transmission lines and disposed near the first transmission line. One end of the first transmission line is connected to a terminating resistor, and the other end of the first transmission line is connected to an anode terminal of a detecting diode through a wideband matching circuit. A cathode terminal of the detecting diode is connected to a load circuit.

Abstract: An antenna duplexer has a power durability to a signal input from an antenna terminal and has stable characteristics. The antenna duplexer includes an input terminal, a transmission filter including a surface acoustic wave (SAW) filter having an input port connected to the input terminal, a phase shifter having an input port connected to an output port of the transmission filter, a reception filter having an input port connected to an output port of the phase shifter, an output terminal connected to the output port of the reception filter, and an antenna terminal connected between the transmission filter and the phase shifter. The transmission filter has a power durability at the input terminal, being equal to or larger than a power durability at the antenna terminal.

Abstract: The present invention relates to a hybrid radio frequency (RF) switching device. It is an object of the invention to provide a hybrid RF switching device including fewer diodes and having a smaller size and high performance. To achieve the object according to the invention, the device includes first to fourth ports, a diode coupled between the first port and second port, a first transmission line having a length of &lgr;g/4 (where &lgr;g is a wave length of a frequency in a first frequency band), and a first element coupled in series with the first transmission line having an almost simple reactance component and nearly opening in a second frequency band. The first transmission line and first element are coupled in series between the second port and third port.

Abstract: The invention relates to a SAW filter, an antenna duplexer using the same, and a mobile communication terminal using the same, and assures a high withstanding power characteristic and a sufficient isolation between transmitting terminal and receiving terminal. The invention relates to a ladder-type SAW filter composed by alternately connecting a serial branch having at least one SAW resonator connected in series to a signal path, and a parallel branch having at least one SAW resonator connected between the signal path and the ground, in which the sizes of wiring patterns of the parallel branch are smaller than wiring patterns of the serial branch. Therefore, in the case of the serial-branch input type, inductive components of the parallel-branch wiring patterns can be decreased, so that a large reflection coefficient may be obtained in the rejection band.

Abstract: A dielectric resonator of the invention includes a cavity having a first threaded hole; a dielectric block provided in the cavity; a coupling device coupled with an electromagnetic field produced in the cavity; a frequency tuning member having a screw portion which is spirally engaged with the first threaded hole of the cavity, a distance between the dielectric block and the frequency tuning member being changed by rotating the frequency tuning member, for tuning a resonance frequency of the cavity depending on the distance; and fixing means for fixing a relative positional relationship between the frequency tuning member and the cavity, wherein the fixing means prevents the frequency tuning member from rotating due to a frictional force caused between the first threaded hole of the cavity and the screw portion of the frequency tuning member, the fixing means including a lock nut having a second threaded hole which is spirally engaged with the screw portion of the frequency tuning member.

Abstract: The present invention relates to a surface acoustic wave (SAW) filter which is used for cellular phones and other mobile communication equipment. The object of the present invention is to realize a SAW filter of which attenuation characteristics and pass characteristics can be set arbitrarily. The SAW filter of the present invention comprises comb-shaped electrodes facing each other disposed on the same piezoelectric substrate, at least two resonators with an input and output terminals, and an equivalent transmission line which is connected between an output terminal of a first resonator and an input terminal of a second resonator. The phase of the transmission line can be adjusted from 5 degrees to 175 degrees arbitrarily at the series resonance frequency of the resonators. This structure realizes a band-stop filter or a band-pass filter whose attenuation characteristics and pass characteristics can be set arbitrarily.

Abstract: A first diode is connected in series to a transmission port, and a low pass filter having transmission band and reception band as passing band is disposed between the first diode and an antenna port. A second diode is connected between the reception port and the ground. A phase shifting function is provided between the first diode and a reception port, having reception band as passing band, so that the impedance as seen from the first diode to the reception port side is almost open in the transmission band when a current flows in the second diode.

Abstract: The present invention relates to a multiplexer/demultiplexer for use in mobile communication devices and provides a small and low-loss multiplexer/demultiplexer. The present invention provides a multiplexer/demultiplexer including a first to a third ports each externally terminated with a pure resistance, in which the second port is made to be a common port by connecting between the first port and the ground a first resonant circuit which makes serial resonance at a frequency within a first frequency band or in its proximity, and further connecting an inductive element in series between the first port and the second port, and connecting between the third port and the ground a second resonant circuit which makes serial resonance at a frequency within a second frequency band which is different from the first frequency band or in its proximity, and further connecting a capacitive element in series between the third port and the second port.

Abstract: The present invention relates to a surface acoustic wave filter used in frequency filter of portable telephone and other mobile communication device, and is intended to realize a surface acoustic wave filter capable of obtaining a stable filter characteristic even in the event of input of a large signal. The invention includes resonators (5) to (8) formed on a piezoelectric substrate (3), through-holes (12) provided near the resonators (5) to (8), and a conductive material (13) filling up the through-holes (12), in which the through-holes (12) filled up with the conductive material (13) are electrically grounded. In this constitution, by the through-holes (12) provided near the resonators (5) to (8) and filled up with the conductive material (13), the heat generated in the resonators (5) to (8) when a large signal is applied to the input terminal (1) can be released, so that a stable filter characteristic may be maintained if a large signal is applied.

Abstract: A dielectric antenna duplexer used in a high frequency radio device such as a portable telephone, and a dielectric filter for forming the duplexer of the SIR (stepped impedance resonator) composed by cascade connection of first transmission lines having one end grounded and second transmission lines having one end open and lower in characteristic impedance than in the first transmission lines, first transmission lines and second transmission lines are individually coupled in electromagnetic field, thereby forming an antenna duplexer and a dielectric filter of small insertion loss, high bandwidth selectivity, excellent band pass characteristic, and low cost.

Abstract: The dielectric notch filter of the invention includes: a transmission line for transmitting a high-frequency signal; input and output terminals provided at both ends of the transmission line; a ground conductor for supplying a ground potential; and a dielectric resonator connected to the ground conductor and the transmission line. The dielectric notch filter further includes an impedance matching element connected to the ground conductor and the transmission line in parallel with the dielectric resonator. The dielectric resonator includes: a cavity connected to the ground conductor; a dielectric block provided in the cavity; a coupling device coupled with an electromagnetic field produced in the cavity; and a coupling adjusting line for connecting the coupling device to the transmission line and for adjusting the degree of electromagnetic coupling.