National Taiwan University

Po-Jui Li

Tzong-Lin Wu

Chi-Hsuan Cheng

Ying-Cheng Tseng

Hsu-Wei Liu

The invention discloses a filter device. The filter device comprises a substrate, at least one transmission conductor, and a reference conductor having a slotted structure. The substrate is provided at a first surface thereof with the transmission conductor, and provided at a second surface thereof with the reference conductor. The slotted structure comprises a frame portion, a slotted portion, and a hollow portion. The slotted portion surrounds the frame portion, and the hollow portion is formed in the frame portion. At least one impedance unit is configured on the frame portion. The equivalent filter circuit of the filter device is formed between the transmission conductor, the slotted structure, the reference conductor, and the impedance unit. Thereby, the equivalent filter circuit absorbs at least one noise at at least one specific frequency by the impedance unit to avoid the noise reflected to affect the transmission quality of signal.

Filter device and equivalent filter circuit thereof

The present invention provides a common-mode signal absorber, which comprises an impedance-matching network and a common-mode signal reflection circuit. A differential-mode signal is inputted into input ends of the impedance-matching network, and outputted from output ends of the common-mode signal reflection circuit. When a common-mode signal is inputted into the common-mode signal absorber, the common-mode signal reflection circuit is for reflecting the common-mode signal within a specific frequency band. Afterward, the reflection of the common-mode signal within the specific frequency band will be absorbed by an impedance element of the impedance-matching network. Thus, the common-mode signal within the specific frequency band may be absorbed by the impedance-matching network so as to avoid to interfere signals transmitted on a communication system.

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Taipei, Taiwan

Po-Jui Li