US 12,394,875 B2
Filter device comprising a substrate having strip-shaped conductors and ground recesses of lengths longer than the strip-shaped conductors
Yusuke Uemichi, Sakura (JP)
Assigned to Fujikura Ltd., Tokyo (JP)
Appl. No. 18/019,848
Filed by FUJIKURA LTD., Tokyo (JP)
PCT Filed Mar. 22, 2021, PCT No. PCT/JP2021/011617
§ 371(c)(1), (2) Date Feb. 6, 2023,
PCT Pub. No. WO2022/044406, PCT Pub. Date Mar. 3, 2022.
Claims priority of application No. 2020-142046 (JP), filed on Aug. 25, 2020.
Prior Publication US 2023/0282952 A1, Sep. 7, 2023
Int. Cl. H01P 1/203 (2006.01)
CPC H01P 1/20363 (2013.01) [H01P 1/203 (2013.01); H01P 1/20336 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A filter device comprising:
a substrate which is made of a dielectric and which includes a first main surface and a second main surface facing each other;
strip-shaped conductors which are provided to the first main surface and adjacent ones of which are electromagnetically coupled to each other; and
a ground conductor layer provided at least to the second main surface, wherein
an area of the first main surface which area is interposed between adjacent ones of the strip-shaped conductors is designated as an intermediate area, and an area of the second main surface which area faces the intermediate area has one or more first recessed portions having a surface covered with the ground conductor layer,
when seen along a lengthwise direction along which the strip-shaped conductors extend, each of the first recessed portions has a length longer than a length of each of two strip-shaped conductors adjacent to the first recessed portion in plan view.