Murata Manufacturing Co., Ltd.

Yu Ishiwata

Takahiro Azuma

Yoshihiro Imanishi

Kota Takayama

Shinya Hirai

Tetsuya Morinaga

Yasushi Saito

Takahiro Aoki

Yoshie Nishikawa

Kiyomi Ikemoto

Yoshimasa Goto

Kenichi Ito

Masashi Omuro

Yasuhisa Yamamoto

Shingo Uda

Tatsumasa Kawahara

Akihiro Ohno

Akiko Shimomura

A method with which the reception sensitivity of a communication device can be measured accurately and with satisfactory reproducibility and a method with which the effect of noise control performed upon a communication device can be accurately evaluated. A first communication device in a nonreflective environment in an anechoic chamber wirelessly receives a test signal transmitted from a pseudo base station through an attached antenna thereof at the same time when a second communication device near the first communication device receives the test signal through a signal line. The first communication device is simultaneously subjected to the interference of noise generated by the second communication device at the attached antenna. Thus, the noise is made to interfere with the attached antenna of the first communication device without disassembling the first communication device and moving the first communication device in the nonreflective environment.

Communication device reception sensitivity measurement method and communication device noise control effect evaluation method using the same

A power supply circuit includes a switching element coupled in a current path between an input terminal and an output terminal and includes a smoothing capacitor coupled between the output terminal and a ground. A bypass capacitor is coupled between the input terminal and the ground. An antenna element shares the ground with the power supply circuit. A frequency filter having a stop band that is an operating frequency band of the antenna element is inserted in series in at least either a current path between the switching element and the smoothing capacitor or a current path between the bypass capacitor and the switching element. It is possible to suppress deterioration of wireless communication quality due to noise caused in a DC-DC converter.

Wireless communication module

A power supply circuit board includes a substrate, a first line that is provided on a first main surface of the substrate and that has a land, a second line that is provided on the first main surface of the substrate and that has a land, an inductor that is connected to the land of the first line and the land of the second line and that is made of a ferrite material, and an open stub that is connected to at least one of the first line and the second line.

Circuit board, inductor, and radio apparatus

A receiver device includes an antenna that receives a high frequency signal having a bandwidth, a mixer connected to the antenna and a frequency multiplier. A filter that removes a noise signal whose frequency is different from that of the local signal is provided between the local oscillator and the frequency multiplier. The filter removes the noise signal that satisfies the condition that the absolute value of the frequency difference between the center frequency of the local signal and the center frequency of the noise signal is less than the bandwidth of the high frequency signal.

Wireless communication device

An S-parameter of an object to be measured is measured, which includes (i) three transmission lines configured such that a ternary signal is transmitted through a corresponding one of the three transmission lines and (ii) six ports as total ports included in the three transmission lines each having a pair of ports. Based on the measured S-parameter, a parameter is calculated, which shows transparent characteristics in each mode among mixed-mode S-parameters in accordance with transition patterns of signal levels on the three transmission lines.

Transmission characteristics measuring method and transmission characteristics measuring apparatus

An electronic apparatus includes a radio communication unit employing a WiGig method and a radio communication unit employing a Wi-Fi method. A bias T circuit is included in the radio communication unit employing the WiGig method. The bias T circuit includes inductors and a filter. The inductors are disposed between a signal line and a DC-DC converter, and are connected in series to each other. The filter has attenuation characteristics in a frequency band used by the radio communication unit employing the Wi-Fi method. One end of the filter is connected between the signal line and one of the inductors located at a first stage from the signal line.

Bias T circuit

Three or more of n inductors are arranged inside an insulating member. Inside the insulating member, each of the inductors includes coil conductors that are contained in respective coil conductor layers that are stacked in a first direction and via conductors, each of which connects the coil conductors that are contained in the coil conductor layers adjoining in the first direction. Each of the coil conductor layers contains the n coil conductors of the inductors, and a pattern formed of the coil conductors contained in each of the coil conductor layers has n-fold rotational symmetry.

Common mode choke coil

A power supply circuit includes a plurality of power amplifiers for amplifying radio frequency signals, an envelope tracker for supplying a variable voltage based on an envelope signal to the power amplifiers, a common line connected to an output side of the envelope tracker, and a plurality of branch lines branching from a tip of the common line and connected to the power amplifiers, respectively. On the branch lines, sub-inductors are provided, respectively. On the common line, a main inductor and a capacitor are provided.

Power supply circuit

A ground conductor film is formed at an insulating substrate. A floating conductor film capacitively couples to the ground conductor film. A radiating element is connected to the floating conductor film. A shielding film shields an electromagnetic wave radiated from the radiating element. By applying such a configuration to a printed circuit board, noise reduction can be achieved.

Printed circuit board

A circuit board with a measure against high frequency noise includes: an interconnect substrate having an interconnect pattern to which an IC which is a source of high frequency noise is electrically connected; a pair of lands provided on a mounting surface of the interconnect substrate; and a chip component having a body composed of a magnetic body (i.e., ferrite) in a rectangular parallelepiped, and a pair of external electrodes provided at opposite ends of the body, the pair of external electrodes being connected to the pair of lands, the body being disposed on the interconnect pattern, as observed in a direction perpendicular to the mounting surface.

Circuit board with measure against high frequency noise

A noise reducing electronic component is used as mounted on a circuit board. The noise reducing electronic component includes: a floating electrode disposed so as to be capacitively coupled to a ground conductor of the circuit board; a radiation element connected to the floating electrode; and a shielding member to shield electromagnetic waves radiated from the radiation element. With this noise reducing electronic component, noise in a printed circuit board and the like can be reduced.

Noise reducing electronic component

A common-mode choke coil includes a core, external electrodes, a pair of wires, and a top plate. The core includes a winding core portion and a pair of flanges at both ends of the winding core portion. The upper surface of the winding core portion and the upper surfaces of the flanges are covered with a metal film. The external electrodes are provided on lower portions of the flanges. A pair of wires are wound on the winding core portion of the core, and the ends of the wires are connected to the external electrodes. The top plate is bonded to the upper surfaces of the flanges preferably via an adhesive.

Common-mode choke coil

A common-mode choke coil has induction immunity characteristics that are improved by a coil structure preventing a transmitter IC and a receiver IC from malfunctioning during an induction immunity test and which controls a decrease in ESD resistance and a decrease in self-resonance frequency. The common-mode choke coil includes a core, external electrodes, a pair of coils, and a top plate. The core includes a core section and a pair of flange sections. The pair of coils are wound around the core section of the core, and the ends of the coils are connected to the external electrodes, respectively. An underside and a side surface of the top plate are plated with a metal film, and bonded to the top surfaces of the flange sections preferably by an adhesive agent. The metal film is segmented into two separate portions so as to define two separate metal sections with a gap therebetween so that the metal sections are electrically disconnected.

A common mode choke coil includes a core, external electrodes, a pair of windings, and a top plate. The core includes a winding core portion and a pair of flanges disposed at respective ends thereof. The external electrodes are provided at lower portions of the flanges. The pair of the windings is wound around the winding core portion of the core, and ends thereof are connected to the external electrodes, respectively. A lower surface and a side surface of the top plate are covered with a metal film and are adhered to upper surfaces of the flanges with an adhesive. Preferably, magnetic powder is mixed in the adhesive.

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Nagaokakyo, Japan

Yu Ishiwata