Murata Manufacturing Co., Ltd.

Tarou Higuchi

Yoshihiro Imanishi

Yasushi Saito

Hiroyuki Honda

Akio Igarashi

Shun Takai

Masaki Inui

Akiko Sakane

Miyuki Nojiri

Yuya Nagaoka

Minehito Yoshida

A multilayer circuit board having a signal and power isolation circuit, which can suppress the capacitive coupling between a chip inductor and a ground layer below the chip inductor and also suppress the characteristic impedance change occurring in a mounting pad on a microstrip line. Portions of the inner-layer ground below both the mounting pad on the microstrip line and the chip inductors connected to the mounting pad are separately removed respectively as the signal transmission characteristic compensation removal portion, which is formed by removing a portion having a predetermined area and situated immediately below the mounting pad, and the inductor characteristic compensation removal portion, which is formed by removing a mounting-surface-below portion having a predetermined area and situated immediately below the chip inductors. The signal transmission characteristic compensation removal portion and the inductor characteristic compensation removal portion are electrically isolated from each other with the predetermined distance therebetween.

Multilayer circuit board having signal and power isolation circuit

A mounting structure for mounting inductors to suppress cross talk and a stub effect due to a mounting land, and reduce deterioration of signal transmission characteristics. A first Bias-T inductor is mounted on a circuit board with one electrode terminal connected to a first mounting land with an axial direction of the first Bias-T inductor oriented perpendicular to the first mounting land and the one electrode terminal extends along the first mounting land. A second Bias-T inductor is mounted on the circuit board in the vicinity of the first Bias-T inductor with one electrode terminal connected to a second mounting land with an axial direction of the second Bias-T inductor inclined by 90° with respect to the axial direction of the first Bias-T inductor and the second Bias-T inductor is oriented perpendicular to the second mounting land and the one electrode terminal extends along the second mounting land.

Mounting structure for inductors

A circuit module includes a wiring board on which are provided a ground plane, a signal line, and a conductive pattern for connection to an outer conductor of a coaxial cable including an inner conductor and the outer conductor. A common-mode choke coil is mounted on the wiring board such that one of coils of the common-mode choke coil connects the ground plane and the conductive pattern and that the other coil is inserted in the signal line. A communication element is mounted on the wiring board and includes a first signal terminal and a second signal terminal. The first signal terminal is connected to the common-mode choke coil via the signal line, and the second signal terminal is connected to the ground plane. A first capacitor is inserted in series in the signal line between the common-mode choke coil and the first signal terminal.

Circuit module, network module, and in-vehicle electronic device

Growing community of inventors

Nagaokakyo, Japan

Tarou Higuchi