Abstract: A communication system includes a transmitter that applies an electric field, obtained by modulating an information signal for wideband communication, to a transmission medium. The transmitter includes a transmission electrode, a transmission circuit that outputs the information signal for the wideband communication, and a first band controller that controls a band of the information signal for the wideband communication. When the transmission medium is in contact with the transmission electrode and the transmission medium and the transmission electrode are capacitively coupled to each other, the first band controller performs control to provide a band that is necessary for a receiver to perform demodulation for the wideband communication, and when the transmission medium is not in contact with the transmission electrode, the first band controller performs control to provide a narrower band than the band that is necessary for the wideband communication.

Abstract: A casing contains a circuit substrate. A signal electrode for transmitting and/or receiving an electronic field signal is arranged on a first surface side of the casing. The signal electrode is electrically connected to a conductor, which is an apparatus component, of the circuit substrate. A battery and a reference electrode having an electric field reference potential, which are apparatus components, are arranged on the second surface side of the casing. The sum (Cst) of a capacitance between the signal electrode and the transmission medium and a capacitance between the apparatus component and the transmission medium generated while the first surface is facing the transmission medium is approximately equal to the sum (Cgt) of capacitances between the apparatus components and the transmission medium generated while the second surface is facing the transmission medium.

Abstract: A portable apparatus of the present invention functions as a transmitter and/or a receiver in electric field communication in which communication is performed through a human body by converting an information signal into an electric field signal; is substantially hexahedron-shaped and provided with sides and an display surface allowing information to be viewed; and includes an outer electrode for electric field communication provided on the display surface and a human-body-side electrode for electric field communication provided on at least one of the sides.

Abstract: A communication system includes a transmitter that applies an electric field, obtained by modulating an information signal for wideband communication, to a transmission medium. The transmitter includes a transmission electrode, a transmission circuit that outputs the information signal for the wideband communication, and a first band controller that controls a band of the information signal for the wideband communication. When the transmission medium is in contact with the transmission electrode and the transmission medium and the transmission electrode are capacitively coupled to each other, the first band controller performs control to provide a band that is necessary for a receiver to perform demodulation for the wideband communication, and when the transmission medium is not in contact with the transmission electrode, the first band controller performs control to provide a narrower band than the band that is necessary for the wideband communication.

Abstract: A communication system according to the present invention includes a transmitter 2 configured to provide an information signal, as an electric field, to a transmission medium 1 and a receiver configured to detect the electric field through the transmission medium 1 and obtain the information signal, and the transmitter 2 includes a resonance unit in which a resonant circuit is formed with two electrodes 221 and 222 individually forming electrostatic capacitances between the transmitter and the transmission medium and an inductor 223 connecting the two electrodes 221 and 222 to each other.

Abstract: A casing contains a circuit substrate. A signal electrode for transmitting and/or receiving an electronic field signal is arranged on a first surface side of the casing. The signal electrode is electrically connected to a conductor, which is an apparatus component, of the circuit substrate. A battery and a reference electrode having an electric field reference potential, which are apparatus components, are arranged on the second surface side of the casing. The sum (Cst) of a capacitance between the signal electrode and the transmission medium and a capacitance between the apparatus component and the transmission medium generated while the first surface is facing the transmission medium is approximately equal to the sum (Cgt) of capacitances between the apparatus components and the transmission medium generated while the second surface is facing the transmission medium.

Abstract: A portable apparatus of the present invention functions as a transmitter and/or a receiver in electric field communication in which communication is performed through a human body by converting an information signal into an electric field signal; is substantially hexahedron-shaped and provided with sides and an display surface allowing information to be viewed; and includes an outer electrode for electric field communication provided on the display surface and a human-body-side electrode for electric field communication provided on at least one of the sides.

Abstract: A surface acoustic wave (SAW) filter includes a SAW chip mounted in a recession of a multi-layer substrate, a sealing plate covering the recession, an end surface electrode that is provided on the outer surface of the substrate and is in conduction with the SAW chip, a metal conductor for radiating heat that is provided on the surface at the opposite side from the sealing plate of the multi-layer substrate, and a through hole provided in the substrate, one end thereof being connected to the metal conductor. The other end of the through hole is connected with the SAW chip through the intermediary of a metal constituent, such as an electrically conductive adhesive layer.

Abstract: A high-frequency module of the invention includes an insulating substrate including a plurality of ceramic thin plates stacked in layers, and an insulating layer formed on the top surface of the insulating substrate. In the high-frequency module, a thin-film circuit is formed on the top surface of the insulating layer, and comprises a wiring pattern and an electrical part comprising a resistor and/or a capacitor. The wiring pattern is formed of a thin film. The electrical part is connected to the wiring pattern and is formed of a thin film. Therefore, the electrical part of the high-frequency module of the invention can be formed more precisely than an electrical part of a related high-frequency module. Consequently, it is possible to provide a high-frequency module having high performance.

Abstract: In a SAW filter module in which a SAW chip is mounted in a recess of a substrate, the recess is closed off by a sealing plate, and end-face electrodes are provided on external surfaces including the side surfaces of the substrate. An insulation layer having a smooth surface is provided on the side opposite to the sealing plate side of the substrate, and a thin film circuit, such as circuit elements, is formed on the insulation layer. A thin film circuit of high accuracy can be formed on the insulation layer, the number of chip components whose pitch between components is severely limited, and miniaturization of the entire module can be achieved.

Abstract: An irreversible circuit element includes a planar ferrite member, a plurality of dielectrics which are formed on the ferrite member in a laminated manner and are made of an insulation material, and the first, the second and the third center conductors which are formed on surfaces different in a vertical direction while sandwiching the dielectrics therebetween and have portions thereof to cross each other in the vertical direction. Accordingly, it is possible to reduce the thickness in the vertical direction so that a thin irreversible circuit element can be provided.

Abstract: A surface acoustic wave (SAW) filter includes a SAW chip mounted in a recession of a multi-layer substrate, a sealing plate covering the recession, an end surface electrode that is provided on the outer surface of the substrate and is in conduction with the SAW chip, a metal conductor for radiating heat that is provided on the surface at the opposite side from the sealing plate of the multi-layer substrate, and a through hole provided in the substrate, one end thereof being connected to the metal conductor. The other end of the through hole is connected with the SAW chip through the intermediary of a metal constituent, such as an electrically conductive adhesive layer.

Abstract: In a SAW filter module in which a SAW chip is mounted in a recess of a substrate, the recess is closed off by a sealing plate, and end-face electrodes are provided on external surfaces including the side surfaces of the substrate. An insulation layer having a smooth surface is provided on the side opposite to the sealing plate side of the substrate, and a thin film circuit, such as circuit elements, is formed on the insulation layer. A thin film circuit of high accuracy can be formed on the insulation layer, the number of chip components whose pitch between components is severely limited, and miniaturization of the entire module can be achieved.

Abstract: A high-frequency module of the invention includes an insulating substrate including a plurality of ceramic thin plates stacked in layers, and an insulating layer formed on the top surface of the insulating substrate. In the high-frequency module, a thin-film circuit is formed on the top surface of the insulating layer, and comprises a wiring pattern and an electrical part comprising a resistor and/or a capacitor. The wiring pattern is formed of a thin film. The electrical part is connected to the wiring pattern and is formed of a thin film. Therefore, the electrical part of the high-frequency module of the invention can be formed more precisely than an electrical part of a related high-frequency module. Consequently, it is possible to provide a high-frequency module having high performance.

Abstract: An irreversible circuit element includes a planar ferrite member, a plurality of dielectrics which are formed on the ferrite member in a laminated manner and are made of an insulation material, and the first, the second and the third center conductors which are formed on surfaces different in a vertical direction while sandwiching the dielectrics therebetween and have portions thereof to cross each other in the vertical direction. Accordingly, it is possible to reduce the thickness in the vertical direction so that a thin irreversible circuit element can be provided.

Abstract: An antenna terminal board device comprising an antenna board body and a cap engageable with the body, in which the terminal board body and the cap each are provided therein with a space, or a groove, for holding an antenna resistor and an antenna coil, respectively. The terminal board body is also provided with a partition wall which is adapted to be inserted in the groove provided in the cap and restrain movement of the antenna coil inserted therein, whereas the cap is also provided with a protruded portion which is adapted to abut on the antenna resistor inserted in the groove provided in the body to restrain movement of the resistor.

Abstract: A band switching circuit of a tuner comprises a tuning circuit, a switching diode connected to the tuning circuit, a pair of band switching terminals coupled across the switching diode. A novel transistor is inserted between one of the band switching terminals and one end of the switching diode with one PN junction of the novel transistor opposing in polarity to the PN junction of the switching diode.

Abstract: An grounding construction of a multilayer printed circuit board includes a metal plate connected to a chassis and provided with at least one upright tab, and two sheets of printed circuit boards for sandwiching the metal plate therebetween. One of the printed circuit boards is formed therein a through hole for passing the upright tab therethrough so as to protrude it from the outer surface thereof. The upright tab is fixedly connected by a solder to a conduction pattern formed around the through hole on the outer surface of the one of the printed circuit boards.

Abstract: In a UHF tuner having a diode mixer and a double-tuned circuit; a UHF tuner of good tuning characteristics comprising the fact that a .pi.-type impedance converter portion consisting of capacitors is disposed in a coupling part between the diode mixer and the double-tuned circuit.

Abstract: A mixer/amplifier circuit for selectively mixing a first input signal with a local oscillator signal or amplifying a second input signal. The mixer/amplifier circuit includes a transistor, a first circuit arrangement responsive to a first switching signal for enabling the transistor to operate as a grounded-base transistor to amplify the second input signal supplied to the emitter thereof, and a second circuit arrangement responsive to a second switching signal for enabling the transistor to operate as a grounded-emitter transistor to mix the first input signal supplied to the base thereof with the local oscillator.