Abstract: An antenna device which includes an antenna structure constituted of a conductive material layer formed on a dielectric planar substrate, and configured to communicate with a radio frequency identification tag, wherein the antenna structure includes an active electrode group, a passive electrode group, and a loop type plane electrode which connects the active electrode group to feeding points, an electromagnetic field is produced between the active electrodes and the passive electrodes by electromagnetic induction, an electromagnetic field which is different from the electromagnetic field in phase is produced between the loop type plane electrode and the passive electrodes by an electromagnetic mutual interference, and electromagnetic field density on the dielectric planar substrate is raised while forming magnetic fields with different phases within the same electromagnetic field.

Abstract: An antenna device which includes an antenna structure constituted of a conductive material layer formed on a dielectric planar substrate, and configured to communicate with a radio frequency identification tag, wherein the antenna structure includes an active electrode group, a passive electrode group, and a loop type plane electrode which connects the active electrode group to feeding points, an electromagnetic field is produced between the active electrodes and the passive electrodes by electromagnetic induction, an electromagnetic field which is different from the electromagnetic field in phase is produced between the loop type plane electrode and the passive electrodes by an electromagnetic mutual interference, and electromagnetic field density on the dielectric planar substate is raised while forming magnetic fields with different phases within the same electromagnetic field.

Abstract: The present invention provides a filing security system which allows files, such as important documents, and the like, to be managed with a simple and low-cost configuration, and a high security.