Security Paper and Detection System Design Using Frequency Selective Surface

In this paper, we designed and fabricated a security paper based on frequency selective surface structure and electromagnetic wave detection system to prevent leakage of confidential documents. In order to detect the document passing through the entrance security gate, the well-known frequency selective surface with the incident angle stability of the incident wave and the low reflection loss performance and the frequency reflection characteristic in the X-band was embedded in plain paper. Designed frequency selective surface was fabricated by screen printing method using conductive ink on plain A4 paper. The fabricated security paper was measured for frequency reflection using free space measurement method. In addition, we fabricated a security paper detection system at the X-band and verified the detection performance according to the distance by measuring the received signal strength reflected from the security paper.