Electronics and Telecommunications Research Institute

Korea Telecommunication

Meyng-Soo Kim

Sang-Seok Lee

Dong-Young Kim

Tae-Goo Choy

Dong-Suk Jun

Chang-Hwa Lee

Bon-Hee Koo

A magnetostatic wave filter that includes a ferromagnetic substance stacked on one side of a dielectric substrate, one side of which is grounded, and the filter includes an input section having an input transfer line and an input energy transformer for causing the energy transformation between an electromagnetic wave and a magnetostatic wave, and an output section having an output energy transformer for causing the energy transformation between the electromagnetic wave and the magnetostatic wave and an output transfer line. The width of exciting lines in the input energy transformer and the output energy transformer varies in a longitudinal direction, the filter includes a shield film formed of a grounded conductive film having holes through which a magnetic thin film can pass between the input section and said output section, to prevent coupling of an electromagnetic wave.

Magnetostatic wave filter

A duplexer having dual coupled line characteristics is disclosed. With a small number of resonators and without using an external device such as a chip inductor or a chip capacitor, the signals of the receiving frequency can be improvingly damped. The diameters of the transmitting terminal dielectric filter resonators and the receiving terminal dielectric filter resonators are not same, but their diameters at an open terminal and at a short circuit terminal are made different from each other so as to differentiate a coupling amount at the short circuit terminal from that at the open terminal. Further, the transmitting terminal filter resonators and the receiving terminal dielectric filter resonator are provided in a form of grooves, and sizes of the grooves near the open terminal are made different from those of the grooves near the short circuit terminal so as to differentiate a coupling amount of the resonators at the short circuit terminal from those at the open terminal. The duplexer of the present invention is used in the transmission/receiving separate type filter of the mobile communication.

Duplexer having dual coupled line characteristics

Growing community of inventors

Daejeon, South Korea

Meyng-Soo Kim