Abstract: A switching power supply apparatus includes: an DC/AC converter unit for converting a DC voltage to an AC voltage based on switching operation of switching devices; a transformer for converting the AC voltage to an AC voltage having a voltage value; a resonance circuit provided between the DC/AC converter unit and the transformer; an AC/DC converter circuit for converting an AC voltage from the transformer to a DC; an output detector unit for detecting an output voltage or an output current of the apparatus; a duty ratio controller unit for controlling a duty ratio of switching of the apparatus such that a detected output voltage or current becomes a target value; an energy detector unit for detecting an energy accumulated in the resonance circuit; and a controller unit for controlling a switching frequency such that a detected energy becomes a threshold value.

Abstract: Disclosed is a coil structure including: a first coil that is a first primary coil; a second coil that is a second primary coil; a first core around which the first coil is wound, the first core having an annular shape; a second core around which the second coil is wound, the second core having an annular shape; and a third coil that is a secondary coil, the first core including a first penetrating section that penetrates the third coil, the second core including a second penetrating section that penetrates the third coil, the first penetrating section being separated from the second penetrating section.

Abstract: A coil structure includes: a magnetic core that defines a closed loop magnetic path in which a magnetic flux flows, the magnetic core including a core leg; a coil that is wound around the core leg about a coil axis extending in a first direction, the coil generating the magnetic flux; a detour member that is separate from the magnetic core, the detour member defining a detour magnetic path that detours around the closed loop magnetic path between first and second points, the detour member including a first piece that defines the first point and a second piece that defines the second point; and a fixing portion that includes an adjoining member adjoining the core leg and a connecting portion connecting at least one of the first piece and the second piece to the adjoining member and fixes positional relations among the core leg and the first and second points.

Abstract: A switching circuit according to an aspect of the present disclosure includes: a full-bridge circuit including a first leg that includes a first switch and a second switch, and a second leg that includes a third switch and a fourth switch; and a control circuit operative to (a) output a first control signal group that changes the first leg into a state in which the third switch is off and the fourth switch is on after changing the first leg into a state in which the first switch is on and the second switch is off, and (b) output a second control signal group that changes the second leg into a state in which the third switch is off and the fourth switch is on before changing the first leg into a state in which the first switch is on and the second switch is off.

Abstract: A coil structure includes a conductor band and a first insulating plate. The conductor band turns around a coil axis in such a manner that the conductor band folds at a plurality of portions which form a plurality of folded portions. The first insulating plate includes a first edge portion which abuts along at least one of the plurality of folded portions. At least part of the conductor band is wound around the first insulating plate.

Abstract: An antenna apparatus includes a dielectric substrate including a ground conductor formed on a back surface thereof, and a radiation conductor formed on a front surface of the dielectric substrate. Upon directly transmitting and receiving a wireless digital signal via a feed point of the radiation conductor, formation of notched portions at sides of the radiation conductor, which intersect an electric field plane defined by an electric field when the antenna apparatus is excited, leads to reduction in the waveform distortion of waveform of the transmitted wireless digital signal.

Abstract: A microstrip line is constituted by including a grounding conductor and a strip conductor with a dielectric substrate being sandwiched between the grounding conductor and the strip conductor. The microstrip line includes a conductor section having at least one groove formed to sterically intersect the strip conductor, thereby exhibiting a substantially more uniform passing characteristic as compared with a prior art microstrip line.

Abstract: A strip conductor is provided on a dielectric board, and a ground conductor facing the strip conductor in a thickness direction of the dielectric board is provided on a surface of the dielectric board. The ground conductor is provided with a plurality of holes penetrating therethrough along the thickness direction of the dielectric board. This structure accomplishes a microstrip line that can obtain consistent passing frequency characteristics.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.

Abstract: A microstrip line is constituted by including a grounding conductor and a strip conductor with a dielectric substrate being sandwiched between the grounding conductor and the strip conductor. The microstrip line includes a conductor section having at least one groove formed to sterically intersect the strip conductor, thereby exhibiting a substantially more uniform passing characteristic as compared with a prior art microstrip line.

Abstract: A surface acoustic wave device in the present invention is provided with a piezoelectric substrate, a supporting substrate being jointed to the piezoelectric substrate and including a material different in expansion coefficient from the piezoelectric substrate and an interdigital electrode for exciting a surface acoustic wave, the electrode being arranged on the surface of the piezoelectric substrate. Either the interdigital electrode or the piezoelectric substrate is configured so that the interdigital electrode is 40% or more to 70% or less as long as the piezoelectric substrate in the direction to which a surface acoustic wave propagates.

Abstract: In order to reduce waveform distortion caused by higher harmonic components of rectangular waveforms reduced as compared with fundamental frequency component when a wireless digital signal is directly and wirelessly transmitted and received by baseband transmission, an antenna apparatus includes a dielectric substrate including a ground conductor formed on a back surface thereof, and a radiation conductor formed on a front surface of the dielectric substrate. Upon directly transmitting and receiving a wireless digital signal via a feed point of the radiation conductor, formation of notched portions at sides of the radiation conductor, which intersect an electric field plane defined by an electric field when the antenna apparatus is excited, leads to reduction in the waveform distortion of waveform of the transmitted wireless digital signal.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.

Abstract: A transmission line pair has two transmission lines placed adjacent to each other in parallel to a signal transmission direction of the transmission lines as a whole. Each of the transmission lines includes a first signal conductor which is placed on one surface of a substrate formed from a dielectric or semiconductor and which is formed so as to be curved toward a first rotational direction within the surface, and a second signal conductor which is formed so as to be curved toward a second rotational direction opposite to the first rotational direction and which is placed in the surface so as to be electrically connected in series to the first signal conductor. A transmission-direction reversal portion in which a signal is transmitted along a direction reversed with respect to the signal transmission direction of the transmission lines as a whole is formed so as to include at least part of the first signal conductor and part of the second signal conductor.

Abstract: A compact, inexpensive antenna sharing device meeting requirements in terms of transmitter distortion characteristic and ESD characteristic is provided which separates and combines signals transmitted and received in first to third signal bands and which thereby enables an antenna terminal to be shared as a common terminal. It includes a diplexer realizing an attenuation characteristic for protection against ESD, a compound semiconductor switch with an IIP3 of 66 dBm or more, and an inexpensive PIN diode switch.

Abstract: A differential transmission line includes: a substrate; a ground conductor layer; and a first and a second signal conductor disposed in parallel to each other on the substrate. The first signal conductor and the ground conductor layer compose a first transmission line, whereas the second signal conductor and the ground conductor layer compose a second transmission line. The first transmission line and the second transmission line compose a differential transmission line. The differential transmission line includes two straight regions and a curved region, interconnecting the two straight regions.

Abstract: A variable-directivity antenna according to the present invention includes at least three linear passive elements, which are arranged parallel to a Z-axis so as to surround a feed element. Each of those passive elements includes at least two element pieces, etc. that are arranged parallel to the Z-axis and switching elements, etc. of a first type. The passive element assembly further includes at least one switching element, etc. of a second type that makes two adjacent passive elements electrically continuous with each other when turned ON but electrically insulates them from each other when turned OFF. By turning ON and OFF the at least one switching element of the first type and the at least one switching element of the second type, the antenna can change its directivities.

Abstract: Inside a multilayer dielectric substrate, there are a spiral-shaped first slot set in a part of a first ground conductor layer and a spiral-shaped second slot in a part of a second ground conductor layer put on the front surface of the multilayer dielectric substrate, the first slot and the second slot are opposite in a spiral winding direction and the first slot and the second slot overlap with each other as viewed from the top face, so that a resonance phenomenon can be produced at a frequency lower than a resonance frequency of a resonator with a conventional structure.

Abstract: A photonic crystal device according to the present invention includes: a first dielectric substrate 104 having a first lattice structure, of which the dielectric constant changes periodically within a first plane; a second dielectric substrate 105 having a second lattice structure, of which the dielectric constant changes periodically within a second plane; and an adjustment device (pivot 303) for changing a photonic band structure, defined by the first and second lattice structures, by varying relative arrangement of the first and second lattice structures. The first and second dielectric substrates 104 and 105 are stacked one upon the other.