Matsushita Electric Industrial Co., Ltd.

Yukihiro Takeda

Hideyuki Miyake

Toshio Ishizaki

Toru Yamada

Makoto Fujikawa

Masaki Kita

Hideki Hayama

Yasumasa Noguchi

Junya Ishii

An antenna duplexer has a transmission input terminal, a receiving output terminal, an antenna terminal in which a transmission output terminal and a receiving input terminal are used in common, a transmission filter having at least one resonance element set between the transmission input terminal and the transmission output terminal and coupled by a coupling element, a receiving filter having at least one resonance element set between the receiving output terminal and said receiving input terminal and coupled by a coupling element, and an impedance variable element connected to the resonance element of the transmission filter and the resonance element of said receiving filter respectively in parallel, wherein the frequency transfer characteristic of the transmission filter and the frequency transfer characteristic of the receiving filter are controlled by applying control signals and thereby changing the impedances of the impedance variable element.

Antenna duplexer

A bandpass filter for the transmission of signals within a predetermined frequency bandwidth having a center frequency, which provides for substantial attenuation of the harmonic components of the center frequency of the filter. The bandpass filter includes at least one resonator comprising a strip conductor and a ground conductor formed on the surface of a dielectric substrate. The strip conductor is capacitively coupled to the ground conductor so as to substantially transmit the harmonic components of the center frequency of the filter to ground.

Co-planar and microstrip waveguide bandpass filter

A dielectric filter comprising: a substrate; a plurality of dielectric coaxial resonators arranged in a row on the substrate; and an inductance element interposed between the dielectric coaxial resonators on the substrate. The plurality of dielectric coaxial resonators are electrically connected in parallel through a capacitance, and relative to said capacitance the inductance element is electrically connected in parallel. The filter has a low overall height and exhibits a good and reliable filter characteristic.

Dielectric filter

Growing community of inventors

Kashihara, Japan

Yukihiro Takeda