Ngk Spark Plug Company, Limited

Keiji Takagi

Manabu Sato

Syouji Ono

Jyunichi Ichikawa

Tetsuo Suehiro

A diplexer provides a high degree of design freedom for satisfying the requirements of electric characteristics so as to realize desired characteristics and at the same time can be downsized and a multiplexer is realized by using such a diplexer. The diplexer includes a filter having a first pass band and a filter having a second pass band with a frequency band at least twice as high as the frequency band of the first pass band, the filter having the first pass band being a filter of the lumped constant type, the filter having the second pass band being a filter of the distributed constant type.

Diplexer and multiplexer using the same

It is possible to generate an additionally attenuation pole in a laminate type band pass filter without adding an attenuation circuit and improve the attenuation characteristics of the laminate type band pass filter by independently controlling the frequencies of the attenuation poles. A diplexer is realized by using at least such a filter. The laminate type band pass filter includes a plurality of first resonators adapted to resonate in a predetermined pass band and arranged in a laminate, the first resonators being mutually electromagnetic field coupled, each of the first resonators having a first inductor conductor, a second inductor conductor and a conductor to be capacitive-coupled to a grounding conductor, the second inductor conductor and the conductor to be capacitive-coupled to the grounding conductor forming a second serial resonator in each of the first resonators, the notch frequency of the second serial resonator being set in a frequency band higher than the resonance frequency band of the first resonator.

Growing community of inventors

Iwakura, Japan

Keiji Takagi