Matsushita Electric Industrial Co., Ltd.

Hideyuki Miyake

Toshio Ishizaki

Toru Yamada

Makoto Fujikawa

Takashi Fujino

Masaki Kita

Yukihiro Takeda

Toshiaki Nakamura

Akira Usui

Hiroyuki Nagai

Shoichi Kitazawa

Kazuhiko Kubo

Takashi Nagata

Hideki Hayama

Ikuo Awai

Nobuhiro Takimoto

Yasumasa Noguchi

Tosiaki Nakamura

Junya Ishii

A notch filter made up from laminated dielectric, which attenuates a specific frequency of a signal to be transmitted, comprises two terminals for input or output a signal to be transmitted, a line connected between those terminals, two resonators each having one end connected to ground and an other end, two first coupling capacitors, and a second coupling capacitor. Each end of the line is connected to the other end of the resonator through the first capacitor. The second capacitor couples said two resonators each other.

Laminated notch filter and cellular phone using the same

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 dielectric filter is made of a dielectric material and includes a molded member of a pillar shape which has a hole formed from the top surface thereof toward the inside, an inner electrode formed so as to cover the inner circumferential surface of the hole; an outer electrode provided so as to cover the outer surface of the molded member except a prescribed region, and a coupling electrode provided at least in a portion of the prescribed region. An electrode area of a region of the inner electrode which faces against the coupling electrode is adjusted, thereby adjusting the coupling capacitance which is formed between the inner electrode and the coupling electrode.

Dielectric filter including an adjusted inner electrode and a coupling

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

Antenna sharing apparatus for switchable transmit/receive filters

On an upper surface of a substrate (20) a band-pass filter (29) is provided, and on the opposite (lower) surface of a substrate (20) a low-pass filter comprising a conductive layer pattern (27) and capacitors (22,23) is provided, wherein a conductive layers (27) are provided on substantially the entire area of the upper surface excluding portions for terminals and on the lower surface excluding portions for the low-pass filter and the terminals, and by connecting both conductive layers by means of a row of through-hole connections, the input terminal (24) and the output terminal (25) are shielded from each other.

Filter apparatus

The disclosure is directed to an improved coaxial resonator such as a .lambda./4 coaxial resonator or the like to be used for an electrical filter or oscillator, etc. which operates, for example, in UHF ranges. The coaxial resonator includes a stator electrode provided on the resonator main body, a rotor of a dielectric material formed with a rotor electrode confronting the stator electrode and rotatably mounted on the resonator main body so as to vary capacity between the stator electrode and the rotor electrode through rotation of the rotor for alterations of the resonance frequency.

Coaxial resonator

Growing community of inventors

Matsubara, Japan

Hideyuki Miyake