Abstract: Provided is a transmission coil which can inhibit reduction in transmission efficiency during underwater non-contact electric power transmission. A transmission coil configured to transmit electric power in water includes an annular electric wire through which an alternating current flows, and a first cover which includes non-conductive resin or non-magnetic resin and seals a periphery of the electric wire. The electric wire transmits the electric power via a magnetic field generated by flowing of the alternating current.

Abstract: An electric power transmission device transmits electric power to an electric power reception device including an electric power reception coil in water. The electric power transmission device includes one or more transmission coils which include an electric power transmission coil configured to transmit electric power to the electric power reception coil via a magnetic field, an electric power transmitter, configured to transmit AC power to the electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonance circuit which resonates with the transmission coil, a first tubular member which is waterproof and seals a periphery of the transmission coil, a second tubular member which surrounds the first tubular member and includes a plurality of holes, and an adjuster, configured to adjust an amount of air in a gap between the first tubular member and the second tubular member.

Abstract: A power transmission device transmits power underwater to a power reception device including a power reception coil. The power transmission device includes: a power transmission coil that transmits power to the power reception coil through a magnetic field; a power transmitter that transmits an alternating current power having a predetermined frequency to the power transmission coil; and a first capacitor that is connected to the power transmission coil and forms a resonance circuit resonating with the power transmission coil. The predetermined frequency is a frequency between a first frequency at which a geometric mean value of a Q value of the power transmission coil and a Q value of the power reception coil are the maximum and a second frequency at which the Q value of the power transmission coil and the Q value of the power reception coil are the same.

Abstract: A power transmitting device transmits power tower power receiving device having a power receiving coil, in water. The power transmitting device includes one or more annular transmitting coils including a power transmitting coil configured to transmit the power to the power receiving coil via a magnetic field, a support member located in an inner space of the transmitting coil, which is formed by the annular transmitting coil, the support member including an outer periphery along an inner periphery of the annular transmitting coil, and supporting the transmitting coil from the inner space, a power transmitting unit configured to supply A/C power to the power transmitting coil, and a capacitor connected to the transmitting coil, and forming a resonance circuit resonating together with the transmitting coil.

Abstract: A mobile terminal is provided with a housing, a circuit board included in the housing and having a thickness direction normal to a plane of the circuit board, a battery pack included in the housing, and a non-contact charging module included in the housing. The non-contact charging module includes a charging coil formed of a wound conducting wire; a communication coil arranged adjacent to the charging coil; and a magnetic sheet on which the charging coil and the communication coil are arranged. The magnetic sheet has four edges that collectively define a rectangular profile of the magnetic sheet, and at most three pairs of adjacent edges respectively meet to form at most three corners. At least a portion of the non-contact charging module overlaps with the circuit board as viewed in the thickness direction of the circuit board.

Abstract: A mobile terminal is provided with a housing having a rectangular shape in a plan view of the housing defined by two short sides along a lateral direction and two long sides along a longitudinal direction. A camera, a battery, and a circuit board are included in the housing. A wireless charging coil is arranged in the housing and includes a winding portion and two leg portions. A sheet is arranged in the housing. The sheet has a rectangular shape including four edges and four corner portions, wherein each pair of adjacent edges forms a virtual corner, each corner portion is receded inwardly from its corresponding virtual corner by a receding distance, and one of four receding distances is greater than other three of the four receding distances.

Abstract: A power transmission device is configured to transmit power underwater to an underwater vehicle having a power reception coil. The power transmission device includes a power transmission coil configured to transmit power to the power reception coil through a magnetic field, a power transmission unit configured to transmit an alternating current voltage having a frequency a 10 kHz or lower to the power transmission coil, and a first capacitor connected to the power transmission coil and configured to form a resonance circuit resonating at the frequency with the power transmission coil.

Abstract: An electric power transmission device capable of efficiently performing contactless electric power transmission to an underwater vehicle in water is provided. The electric power transmission device, which is an electric power transmission device transmitting electric power to an electric power reception device including an electric power reception coil in water, includes one or more transmission coils including an electric power transmission coil which transmits electric power to an electric power reception coil via a magnetic field, an electric power transmission unit which transmits AC power to an electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonant circuit which resonates with the transmission coil, and a buoyant body connected to at least one of the transmission coils.

Abstract: A terminal includes an RF-DC conversion circuit outputting DC current by converting AC current received via wireless communication into DC current, a DC-DC converter connected to an output side of RF-DC conversion circuit to convert a voltage of DC current output from RF-DC conversion circuit to a predetermined voltage, and a controller controlling connection and disconnection between RF-DC conversion circuit and DC-DC converter. Controller acquires open circuit voltage Vin_oc on an output side of RF-DC conversion circuit, which is obtained when RF-DC conversion circuit and DC-DC converter are disconnected from each other, and target voltage ?Vin_oc (0<?<1) obtained by dividing open circuit voltage Vin_oc. When RF-DC conversion circuit and DC-DC converter are connected to each other, controller performs feedback control of DC-DC converter so that an input voltage Vin on a side where DC-DC converter is connected to RF-DC conversion circuit is equal to target voltage ?Vin_oc.

Abstract: An energy harvest terminal includes a distribution circuit that distributes input radio wave power to at least two branch paths, a main rectification circuit that converts first radio wave power supplied to one of the at least two branch paths from the distribution circuit into DC output power, a DC-DC converter that performs voltage conversion on the DC output power of the main rectification circuit, a sub-rectification circuit that converts second radio wave power supplied to another of the at least two branch paths from the distribution circuit into DC output power, and an electricity storage device connected to an output of the DC-DC converter. The DC-DC converter performs a feedback control for equalizing an output voltage of the main rectification circuit and an output voltage of the sub-rectification circuit.

Abstract: An antenna device includes a substrate having a ground conductor, an antenna conductor disposed approximately parallel with the ground conductor with an air layer or a dielectric layer, plural short-circuiting conductors that connect the antenna conductor to the ground conductor, and a feed conductor disposed in a vicinity of one of the plural short-circuiting conductors and that feeds the antenna conductor with power. When a wavelength of frequency used in the antenna device is represented by ?, an outer circumferential length of the slot is approximately 1? to 2? and a width of the slot is 0.005? to 0.05?, an interval between the plural short-circuiting conductors is shorter than or equal to ?/2, and a distance between the antenna conductor and the ground conductor is 0.005? to 0.05?.

Abstract: A power transmission device transmits power underwater to a power reception device including a power reception coil. The power transmission device includes: a power transmission coil that transmits power to the power reception coil through a magnetic field; a power transmitter that transmits an alternating current power having a predetermined frequency to the power transmission coil; and a first capacitor that is connected to the power transmission coil and forms a resonance circuit resonating with the power transmission coil. The predetermined frequency is a frequency between a first frequency at which a geometric mean value of a Q value of the power transmission coil and a Q value of the power reception coil are the maximum and a second frequency at which the Q value of the power transmission coil and the Q value of the power reception coil are the same.

Abstract: A mobile terminal is provided with a housing having a rectangular shape in a plan view of the housing defined by two short sides along a lateral direction and two long sides along a longitudinal direction. A camera, a battery, and a circuit board are included in the housing. A wireless charging coil is arranged in the housing and includes a winding portion and two leg portions. A sheet is arranged in the housing. The sheet has a rectangular shape including four edges and four corner portions, wherein each pair of adjacent edges forms a virtual corner, each corner portion is receded inwardly from its corresponding virtual corner by a receding distance, and one of four receding distances is greater than other three of the four receding distances.

Abstract: A mobile terminal is provided with a housing, a circuit board included in the housing and having a thickness direction normal to a plane of the circuit board, a battery pack included in the housing, and a non-contact charging module included in the housing. The non-contact charging module includes a charging coil formed of a wound conducting wire; a communication coil arranged adjacent to the charging coil; and a magnetic sheet on which the charging coil and the communication coil are arranged. The magnetic sheet has four edges that collectively define a rectangular profile of the magnetic sheet, and at most three pairs of adjacent edges respectively meet to form at most three corners. At least a portion of the non-contact charging module overlaps with the circuit board as viewed in the thickness direction of the circuit board.

Abstract: An antenna device includes a first plate conductor that is disposed approximately in parallel to the GND conductor plate, of which one end is connected to the GND conductor plate, and the other end that is opposed to the one end is opened, and a second plate conductor that has approximately the same shape as that of the first plate conductor, of which one end is grounded to the GND conductor plate, of which the other end that is opposed to the one end is opened, that is disposed at a position obtained by rotating the first plate conductor approximately 180 degrees about an intersection line passing through an approximately central point of the GND conductor plate as an axis on the same plane as the first plate conductor on the GND conductor plate, and that has a ground portion at which the grounding is performed and an open portion at which the opening is performed at positions obtained by rotating the ground portion and the open portion of the first plate conductor approximately 180 degrees about the axis.

Abstract: An electronic device having a communication capability is provided. The electronic device includes a housing having a generally rectangular shape in a plan view of the housing, and a non-contact charging module included in the housing. The non-contact charging module includes (i) a wireless charging coil having a substantially planar shape and formed of a wound electrical wire, and (ii) a magnetic sheet that overlaps with the wireless charging coil in the plan view of the housing. The electronic device further includes a Near Field Communication (NFC) antenna included in the housing and including an NFC coil formed of a wound electrical wire, and a guide having a generally rectangular outer shape in the plan view of the housing. The guide has a hole and the wireless charging coil is arranged in the hole of the guide.

Abstract: A mobile terminal is provided with a housing, a circuit board included in the housing and having a thickness direction normal to a plane of the circuit board, a battery pack included in the housing, and a non-contact charging module included in the housing. The non-contact charging module includes a charging coil formed of a wound conducting wire; a communication coil arranged adjacent to the charging coil; and a magnetic sheet on which the charging coil and the communication coil are arranged. The magnetic sheet has four edges that collectively define a rectangular profile of the magnetic sheet, and at most three pairs of adjacent edges respectively meet to form at most three corners. At least a portion of the non-contact charging module overlaps with the circuit board as viewed in the thickness direction of the circuit board.

Abstract: An electronic device having a communication capability is provided. The electronic device includes a housing having a generally rectangular shape in a plan view of the housing, and a non-contact charging module included in the housing. The non-contact charging module includes (i) a wireless charging coil having a substantially planar shape and formed of a wound electrical wire, and (ii) a magnetic sheet that overlaps with the wireless charging coil in the plan view of the housing. The electronic device further includes a Near Field Communication (NFC) antenna included in the housing and including an NFC coil formed of a wound electrical wire, and a guide having a generally rectangular outer shape in the plan view of the housing. The guide has a hole and the wireless charging coil is arranged in the hole of the guide.

Abstract: A power transmission device is configured to transmit power underwater to an underwater vehicle having a power reception coil. The power transmission device includes a power transmission coil configured to transmit power to the power reception coil through a magnetic field, a power transmission unit configured to transmit an alternating current voltage having a frequency a 10 kHz or lower to the power transmission coil, and a first capacitor connected to the power transmission coil and configured to form a resonance circuit resonating at the frequency with the power transmission coil.

Abstract: A terminal includes an RF-DC conversion circuit outputting DC current by converting AC current received via wireless communication into DC current, a DC-DC converter connected to an output side of RF-DC conversion circuit to convert a voltage of DC current output from RF-DC conversion circuit to a predetermined voltage, and a controller controlling connection and disconnection between RF-DC conversion circuit and DC-DC converter. Controller acquires open circuit voltage Vin_oc on an output side of RF-DC conversion circuit, which is obtained when RF-DC conversion circuit and DC-DC converter are disconnected from each other, and target voltage ?Vin_oc (0<?<1) obtained by dividing open circuit voltage Vin_oc. When RF-DC conversion circuit and DC-DC converter are connected to each other, controller performs feedback control of DC-DC converter so that an input voltage Vin on a side where DC-DC converter is connected to RF-DC conversion circuit is equal to target voltage ?Vin_oc.