This study designed and fabricated a frequency-selective structure-based security paper for the electromagnetic detection system of\na security gate, which aims to prevent leakage of confidential documents. When a functional paper embedded with a frequencyselective\npattern that selectively reflects a specific frequency is being leaked out of a security zone, the electromagnetic detection\nsystem receives and detects the intensity of the electromagnetic wave reflected from the security paper passing through an\nantenna gate, which transmits/receives RF signals. A stable detection performance of the security paper can be ensured by\nimproving the incidence angle stability for incident waves and reducing the reflection loss. This study designed a frequencyselective\nstructure with stable frequency reflection properties at the X-band by utilizing a Jerusalem cross structure. The\nproposed design was realized using the screen printing technique, which could implement a circuit, to print silver ink on a plain\npaper. To verify the applicability of the frequency-selective structure-based security paper, an RF detection system with a\nmultiple antenna array was constructed and the intensity of the received signals was measured. The measurement was\nperformed for various scenarios, and the result showed that the proposed security paper was well detected.
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