Murata Manufacturing Co., Ltd.

Naoto Yamaguchi

Takanori Uejima

Tetsuro Harada

Naoki Nakayama

Hidehiro Takano

Koki Saito

A balanced/unbalanced filter module includes a switch including a first port that inputs and outputs unbalanced signals in a first frequency band, a second port that inputs and outputs unbalanced signals in a second frequency band, and a third port that inputs and outputs unbalanced signals in these two frequency bands. The switch switches a signal path. An unbalanced I/O port of a first filter that passes signals in the first frequency band is connected to the port. A port of a second filter that passes signals in the second frequency band is connected to the port. Individual balanced I/O ports of each of the first and second filters are connected to first and second branch ports with substantially the same electrical length. A balance coil for impedance matching is provided between the first and second branch ports.

Balanced/unbalanced filter module and communication apparatus

An LC high-pass filter circuit device includes an inductor defined by via holes formed in adjacent insulating sheets which are connected in the direction of stacking of the sheets so as to define a single trap inductor. Inductor via holes formed in another insulating sheet define separate high-pass filter inductors. The trap inductor and the high-pass filter inductors have axes which extend substantially perpendicularly to the planes of the insulating sheets. Each of the high-pass circuit inductors defines, in combination with a high-pass filter capacitor, a high-pass filter circuit, while the trap inductor defines, in combination with a capacitor, a trap circuit. The high-pass filter circuits and the trap circuit in combination define a small-sized LC high-pass filter circuit device which exhibits high Q value and which excels in frequency characteristics, as well as a laminated LC high-pass filter device, a multiplexer and a radio communication apparatus incorporating the LC high-pass filter circuit device.

LC high-pass filter circuit device, laminated LC high-pass filter device, multiplexer, and radio communication apparatus

An LC filter circuit includes first and second LC-trap capacitor conductors, respectively, that are opposed to third and LC-trap capacitor conductors with an insulating sheet therebetween to define first and second LC trap capacitors, respctively. A portion of a first LC resonator inductor and the first LC trap capacitor define an input-side LC trap circuit, and a portion of a second LC resonator inductor and the second LC trap capacitor define an output-side LC trap circuit.

LC filter circuit, monolithic LC composite component, multiplexer, and radio communication device

A multi-layered LC composite component achieves greatly increased attenuation in the proximity of a central frequency without increasing insertion loss. In the arrangement of the multi-layered LC composite component, an end of each of inductor patterns is connected to a connecting pattern to be short-circuited. These inductor patterns define inductors. Frequency-adjusting capacitor patterns are opposed to open-circuited ends of the inductor patterns to define capacitors. As a result, the capacitors and the inductors define LC resonators. The connecting pattern is opposed to shield patterns via insulating sheets to define a common capacitor.

Multilayered LC composite with via hole inductors having a connecting pattern forming a group capacitor

A multilayer LC composite component is constructed for allowing for free and easy setting of an attenuation pole formed at a frequency higher than the central frequency to adjust the frequency characteristics of the LC composite component. In the multilayer LC composite component, inductor via-holes are connected in the direction in which insulation layers are stacked to constitute first to third pillar inductors. In the axial directions of the first and third inductors, input and output lead patterns are electrically connected to midpoints of the first and third inductors. A distance between a ground pattern and each of positions at which the input and output lead patterns are electrically connected to the first and third inductors is shorter than the length of each of the first and third inductors.

Growing community of inventors

Shiga-ken, Japan

Naoto Yamaguchi