Printed wiring board

A printed wiring board comprising:

• a power supply layer;
• a ground layer;
• a power supply layer pattern formed partially on the power supply layer;
• a branch formed within the power supply layer pattern, wherein the branch is a direct-current power feeding path for connecting adjacent electromagnetic band gap (EBG) unit cells;
• a power supply layer electrode formed within the power supply layer pattern;
• a slit formed within the power supply layer pattern that partially separates the branch and the power supply layer electrode, wherein the power supply layer electrode includes a connection portion that connects the power supply layer electrode to the branch across the slit
• a capacitive coupling element that is disposed to oppose the power supply layer electrode;
• and
• an interlayer that is disposed between the capacitive coupling element and the power supply layer electrode,
• wherein the EBG unit cells incorporate the capacitive couple element and are arranged at regular intervals and connected to the branch in the power supply layer pattern through a via in the branch.