Fig. 4. (Color online) The photographs and microwave near field distributions of the real copied 1000 won and 5000 won bills. (a) Photograph of the real 1000 won bill. (b–d) Microwave near-field distributions of the real 1000 won bill measured at 11 GHz, 12 GHz, and 13 GHz, respectively. (e) Photograph of the copied 1000 won bill. (f–h) Microwave near-field distributions of the copied 1000 won bill measured at 11 GHz, 12 GHz, and 13 GHz, respectively. (i) Photograph of the real 5000 won bill. (j–l) Microwave near-field distributions of the real 5000 won bill measured at 11 GHz, 12 GHz, and 13 GHz, respectively. (m) Photograph of the copied 5000 won bill. (n–p) Microwave near-field distributions of the copied 5000 won bill measured at 11 GHz, 12 GHz, and 13 GHz, respectively. The dashed red and white circles indicate locations of hologram marks.
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