Murata Manufacturing Co., Ltd.

Nobuyoshi Honda

Masayuki Atokawa

Tatsuya Tsujiguchi

Hajime Suemasa

Yasunori Takei

Kyoji Matsunaga

The element size of a stripline filter that achieves a high efficiency percentage with optional stable filter characteristics, is reduced. A stripline filter includes substantially L-shaped top surface resonant lines. The top surface resonant lines include connection electrode parts, first line parts, and second line parts. The connection electrode parts are formed so as to have a width greater than line widths of side surface resonant lines. Each line part faces an edge of a corner portion of a central top surface resonant line at an interval. An edge of each first line part on an edge side of a dielectric substrate, other than a connection portion with the connection electrode part, faces an edge of the dielectric substrate at an interval.

Stripline filter and manufacturing method thereof

A shared-antenna device having a transmission circuit electrically connected between a transmission terminal and an antenna terminal, and a reception circuit electrically connected between a reception terminal and the antenna terminal. The transmission circuit is a variable-frequency band-stop filter circuit and the reception circuit is a variable-frequency bandpass filter circuit. Control-voltage supplying resistors are connected to the PIN diodes such that the DC voltages for individually controlling the PIN diodes are applied to the PIN diodes via only the resistors.

Variable-frequency resonator circuit, variable-frequency filter, shared-antenna device, and communication device

A duplexer comprising: &lgr;/4-type dielectric coaxial resonators constituting a transmitting-side filter; &lgr;/4-type dielectric coaxial resonators constituting a receiving-side filter; and coupling elements for coupling said resonators; wherein the dielectric coaxial resonators constituting the transmitting-side filter and the dielectric coaxial resonators constituting the receiving-side filter are placed in parallel; and the open end surfaces of the dielectric coaxial resonators constituting the transmitting-side filter and the open end surfaces of the dielectric coaxial resonators constituting the receiving-side filter are disposed in opposite directions, and/or are alternately disposed side-by-side.

Duplexer and communication apparatus including the same

In an antenna-sharing device, a transmission filter is electrically connected between a transmission terminal and an antenna terminal, and a reception filter is electrically connected between a reception terminal and the antenna terminal. A signal pattern and a ground electrode are formed on a resonator-mounting surface of a circuit substrate. On the ground electrodes, the resonators constituting the transmission filter are integrally soldered and the resonators constituting the reception filter are integrally soldered. On the mounting surface of the circuit substrate, a transmission filter ground electrode and a reception filter ground electrode are formed. Both ground electrodes are isolated from each other by a gap (slit), and are disconnected from each other.

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Kanazawa, Japan

Nobuyoshi Honda