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.