In one embodiment of the present invention, a conductive pattern portion formed in a pattern layer functions as an antenna, and, when electromagnetic
waves at a predetermined frequency arrive,
resonance occurs, and an electromagnetic wave of a specific frequency is introduced into a sheet member. As to the sheet member having the pattern layer, even in a small and
thin sheet member, the phase of
reflected waves from the reflection area can be adjusted, and thus an area having high
electric field intensity due to interference between
reflected waves from the reflection area and arriving electromagnetic
waves can be set in the vicinity of the
antenna element. When the sheet member is disposed between an
antenna element and a communication jamming member, an
electromagnetic field is generated around the conductive pattern portion, and an electromagnetic energy is supplied from the conductive pattern portion to the
antenna element, and therefore receiving power of the antenna element can be increased. Accordingly,
wireless communication can be suitably performed.