Patent ID: 8420949

Claim:
An electromagnetic bandgap structure comprising: a dielectric layer; a plurality of conductive plates; a conductive layer; and a plurality of stitching vias connecting conductive plates that are adjacent to each other, each stitching via comprising: a first via, passing through the dielectric layer and having an end part being placed on a same planar surface as one of two conductive plates, a second via, passing through the dielectric layer and having an end part being placed on a same planar surface as the other of the two conductive plates, a connection pattern, having one end part being connected to the other end part of the first via and the other end part being connected to the other end part of the second via, the first via and the second via being serially connected through the connection pattern, and a first extension pattern, placed on a same planar surface as the one of the two conductive plates and having one end part being connected to the one end part of the first via and the other end part being connected to the one of the two conductive plates, wherein the dielectric layer is placed between the conductive plates and the conductive layer, the conductive layer comprises a clearance hole, and the connection pattern is accommodated in the clearance hole, the stitching via further comprises a second extension pattern, placed on a same planar surface as the other of the two conductive plates and having one end part being connected to the one end part of the second via and the other end part being connected to the other of the two conductive plates, and each of the conductive plates, with the exception of the conductive plates that are not placed in outermost areas of the two-dimensionally arranged conductive plates, are respectively connected with at least three of the stitching vias connecting adjacent conductive plates among the conductive plates arranged two-dimensionally on a same planar surface.