Abstract: Provided is a wireless communication system which has excellent communication characteristics even between antenna modules having antenna coils between which there is a large difference in outside diameter. The wireless communication system includes: a first antenna module including a first antenna coil; and a second antenna module including a second antenna coil and capable of communication by receiving a magnetic field transmitted from the first antenna module, in which the first antenna coil and the second antenna coil have mutually different outside diameters, and, out of the first antenna coil and the second antenna coil, the antenna coil having a larger outside diameter is formed in such a way that the area of an opening portion inside the innermost perimeter of an antenna pattern is not more than 120% of the outside diameter area of the other antenna coil having a smaller outside diameter.

Abstract: An electronic device and an antenna device are provided that use a coil module which is thinned without losing the characteristics of the coil module and which can be mounted in a narrowed space. A coil module including a loop-shaped antenna coil wounded in a planar shape and a sheet-shaped magnetic sheet which is formed of a magnetic material and which overlaps with at least a part of the antenna coil is included. In the coil module, a part of the antenna coil is overlapped with an internal structure of a housing and the magnetic sheet is provided in a position that does not overlap with the internal structure on an antenna coil surface side that overlaps with the internal structure.

Abstract: The loss is reduced even when loop coils of a multi-coil module are overlaid with each other. The multi-coil module includes a first coil module, having a first magnetic sheet and a first loop coil provided on the first magnetic sheet and wound in a planar shape, and a second coil module, having a second magnetic sheet and a second loop coil provided on the second magnetic sheet and wound in a planar shape. The first coil module and the second coil module are stacked on each other, and at least an innermost coil pattern of the first loop coil and the second loop coil are overlaid with each other. The line width of the innermost coil pattern t of the first loop coil overlaid with the second loop coil is 1 mm or less.

Abstract: A decreased thickness is realized without loss of characteristics of a plurality of coil modules. A first coil module includes a first magnetic sheet made of a first magnetic material, and a first loop coil provided on the first magnetic sheet and wound in a plane. A second coil module includes a second magnetic sheet made of a second magnetic material different from that of the first magnetic sheet, and a second loop coil provided on the second magnetic sheet and wound in a plane. The first magnetic sheet is not provided and the second coil module is provided inside the first loop coil.

Abstract: Provided is an antenna device that achieves good communication characteristics when incorporated into an electronic apparatus. The antenna device incorporated into an electronic apparatus and configured to communicate with an external device via an electromagnetic field signal comprises: a metal plate serving as a first electric conductor, being provided inside a casing of the electronic apparatus and facing the external device; an antenna substrate provided inside the casing of the electronic apparatus, and having an antenna coil inductively coupled to the external device and wound around thereon; and metal foil serving as a second electric conductor in sheet form, being provided inside the casing of the electronic apparatus, overlapping or being in contact with the metal plate serving as the first electric conductor, and at least partially overlapping a surface of the antenna substrate, the surface being opposite to a surface facing the external device.

Abstract: Provided is a portable communication device including a receiver, a transmitter, an adjustment signal generator, an adjustment signal detector, and a control circuit unit. The transmitter transmits an adjustment signal to the receiver in order to adjust a received resonant frequency. The adjustment signal detector detects a parameter including information on a transmission state of the adjustment signal at a time of transmitting the adjustment signal. Then, the control circuit unit corrects a deviation of the received resonant frequency based on a detection result of the adjustment signal detector.

Abstract: An antenna device, capable of stable communications without increasing a space of the entire device by keeping a resonance frequency substantially constant even if the temperature changes, includes: an antenna circuit having an antenna coil with an electrically connected capacitor; the coil receiving a magnetic field transmitted from a reader/writer at a predetermined oscillation frequency; the circuit becoming communicable when inductively coupled to the reader/writer; and a magnetic sheet formed at a position superposed on the coil to change its inductance, wherein the coil has a temperature characteristic in which the inductance is changed with a temperature change, and the sheet has a temperature characteristic of changing the inductance to achieve a characteristic inverse to the inductance change with the temperature change in a predetermined use temperature range, and substantially matching a resonance frequency of the circuit with the oscillation frequency in the use temperature region.

Abstract: An antenna device that is built in an electronic device and that can perform communication by receiving a magnetic field transmitted from a transmitter includes an antenna coil formed on a printed circuit board and inductively coupled to the transmitter, and a magnetic sheet that attracts the magnetic field transmitted from the transmitter to the antenna coil. The antenna coil and the magnetic sheet are superposed on each other.

Abstract: The present invention provides a communication device that can reduce a housing of an electronic device in size and thickness when the communication device is built in the electronic device. The communication device includes: an antenna coil (11a) arranged on an outer peripheral portion (134) of a housing (131) surface facing a reader/writer (120) of a mobile phone (130); a magnetic sheet (13) that attracts a magnetic field transmitted from the reader/writer (120) to the antenna coil (11a); and a communication processing unit (12) that is driven by a current flowing in the antenna coil (11a) and performs communication with the reader/writer (120), wherein the magnetic sheet (13) is arranged on the reader/writer (120) side of the antenna coil (11a) at a center portion (132a), and the antenna coil (11a) is arranged on the reader/writer (120) side on an outer periphery (130d) side.

Abstract: A method for manufacturing an antenna device may include a first step of forming an antenna circuit so that the resonance frequency of the antenna circuit will be lower than an oscillation frequency of the reader/writer. The antenna circuit includes an antenna coil that receives the magnetic field transmitted from the reader/writer and a capacitor electrically connected to the antenna coil. The manufacturing method also includes a second step of affixing a magnetic sheet to the antenna coil via an adhesive. The magnetic sheet is at a face-to-face position with respect to the antenna coil and is configured to change the inductance of the antenna coil. The adhesive is of a film thickness to change the inductance so that the resonance frequency of the resonance circuit will be coincident with the oscillation frequency depending on the spacing between the antenna coil and the magnetic sheet.

Abstract: A method for manufacturing an antenna device is provided. The manufacturing method includes forming an antenna circuit so that the resonance frequency of the antenna circuit will be lower than an oscillation frequency of the reader/ writer and affixing a magnetic sheet to an antenna coil via an adhesive. The antenna circuit includes the antenna coil that receives the magnetic field transmitted from the reader/ writer and a capacitor electrically connected to the antenna coil. The magnetic sheet is at a face-to-face position with respect to the antenna coil and is configured to change the inductance of the antenna coil. The adhesive is of a film thickness to change the inductance so that the resonance frequency of the resonance circuit will be coincident with the oscillation frequency depending on the spacing between the antenna coil and the magnetic sheet.

Abstract: The present invention provides an antenna apparatus which can realize favorable communication properties while achieving downsizing of a casing of an electronic device when incorporated in an electronic device. An antenna module (1a) which is incorporated in a mobile phone (130) and which is enabled to perform communication by receiving a magnetic field transmitted from a reader/writer (120) comprises an antenna coil (11a) which is wound in a clearance (132) between an end portion (133b) of a metallic plate (133a) opposing the reader/writer (120) within a casing (131) of the mobile phone (130) and an inner peripheral wall (131a) of the casing (131) so as not to surround an outer peripheral portion of the metallic plate (133a) and which is inductively coupled with the reader/writer (120).

Abstract: A method for reducing a resistance of an antenna circuit capable of obtaining a desired property by reducing wiring resistance to a suitable value while ensuring inductance is provided. An antenna circuit is disposed to a transponder having a carrier frequency band of 13.56 MHz. The antenna circuit is formed of a prescribed base material and two antenna conductors each of which is formed of the same conductor pattern forming an antenna coil, formed on respective front and back surfaces of the base material by electrically parallel connection. Each of the two antenna conductors has a thickness of greater than equal to 5% and less than 50% of an overall thickness formed of the two antenna conductors and the base material.

Abstract: Provided is a portable communication device including a receiver, a transmitter, an adjustment signal generator, an adjustment signal detector, and a control circuit unit. The transmitter transmits an adjustment signal to the receiver in order to adjust a received resonant frequency. The adjustment signal detector detects a parameter including information on a transmission state of the adjustment signal at a time of transmitting the adjustment signal. Then, the control circuit unit corrects a deviation of the received resonant frequency based on a detection result of the adjustment signal detector.

Abstract: A communication device that, when incorporated in an electronic device, can reduce the size and the thickness of a housing of the electronic device while maintaining communication characteristics. The communication device includes an antenna coil that is arranged on a peripheral part of a housing surface facing a reader-writer of a mobile phone, a magnetic sheet that attracts the magnetic filed transmitted from the reader-writer to the antenna coil, and a communication processing unit that is driven by a current flowing through the antenna coil and communicates with the reader-writer. The magnetic sheet is arranged to be closer to reader-writer than the antenna coil in the central part, and the antenna coil is arranged to be closer to the reader-writer on the outer periphery side, and at least a part of the conductive line of the antenna coil is superimposed in a direction orthogonal to a circuit board.

Abstract: An antenna device, capable of stable communications without increasing a space of the entire device by keeping a resonance frequency substantially constant even if the temperature changes, includes: an antenna circuit having an antenna coil with an electrically connected capacitor; the coil receiving a magnetic field transmitted from a reader/writer at a predetermined oscillation frequency; the circuit becoming communicable when inductively coupled to the reader/writer; and a magnetic sheet formed at a position superposed on the coil to change its inductance, wherein the coil has a temperature characteristic in which the inductance is changed with a temperature change, and the sheet has a temperature characteristic of changing the inductance to achieve a characteristic inverse to the inductance change with the temperature change in a predetermined use temperature range, and substantially matching a resonance frequency of the circuit with the oscillation frequency in the use temperature region.

Abstract: The present invention provides a communication device that can reduce a housing of an electronic device in size and thickness when the communication device is built in the electronic device. The communication device includes: an antenna coil (11a) arranged on an outer peripheral portion (134) of a housing (131) surface facing a reader/writer (120) of a mobile phone (130); a magnetic sheet (13) that attracts a magnetic field transmitted from the reader/writer (120) to the antenna coil (11a); and a communication processing unit (12) that is driven by a current flowing in the antenna coil (11a) and performs communication with the reader/writer (120), wherein the magnetic sheet (13) is arranged on the reader/writer (120) side of the antenna coil (11a) at a center portion (132a), and the antenna coil (11a) is arranged on the reader/writer (120) side on an outer periphery (130d) side.

Abstract: A method for manufacturing an antenna device may include a first step of forming an antenna circuit so that the resonance frequency of the antenna circuit will be lower than an oscillation frequency of the reader/writer. The antenna circuit includes an antenna coil that receives the magnetic field transmitted from the reader/writer and a capacitor electrically connected to the antenna coil. The manufacturing method also includes a second step of affixing a magnetic sheet to the antenna coil via an adhesive. The magnetic sheet is at a face-to-face position with respect to the antenna coil and is configured to change the inductance of the antenna coil. The adhesive is of a film thickness to change the inductance so that the resonance frequency of the resonance circuit will be coincident with the oscillation frequency depending on the spacing between the antenna coil and the magnetic sheet.

Abstract: An antenna device includes an antenna coil that receives a magnetic field transmitted from a reader/writer and a capacitor. The antenna device also includes a magnetic sheet formed at a face-to-face position with respect to the antenna coil and configured for changing the inductance of the antenna coil. The capacitor has a temperature characteristic in which the capacitance of the capacitor is changed with changes in temperature. The magnetic sheet is formed of a magnetic material having a temperature characteristic in which the inductance of the antenna coil is made to be changed with an opposite sign of change to that of the capacitance of the capacitor that is changed with changes in temperature in the working temperature range. In this manner, the resonance frequency of the antenna circuit in the working temperature range may be brought approximately into coincidence with the oscillation frequency of the reader/writer.

Abstract: A method for manufacturing an antenna device is provided. The manufacturing method includes forming an antenna circuit so that the resonance frequency of the antenna circuit will be lower than an oscillation frequency of the reader/writer and affixing a magnetic sheet to an antenna coil via an adhesive. The antenna circuit includes the antenna coil that receives the magnetic field transmitted from the reader/writer and a capacitor electrically connected to the antenna coil. The magnetic sheet is at a face-to-face position with respect to the antenna coil and is configured to change the inductance of the antenna coil. The adhesive is of a film thickness to change the inductance so that the resonance frequency of the resonance circuit will be coincident with the oscillation frequency depending on the spacing between the antenna coil and the magnetic sheet.