Development of Optically Transparent Ultrathin Microwave Absorber for Suppression of Misidentification Possibility of UHF‐RFID System

Abstract

SUMMARYRecently, wireless telecommunication devices have been used with the worldwide spread of the mobile phone, wireless local area networks (WLAN), and UHF‐radio frequency identification (UHF‐RFID). Therefore, EMI problems have also been serious. In the case of indoor use, the wireless telecommunication environment is degraded by multiple reflection interference. That interference must be controlled in order to improve wireless communication conditions. In particular, improvement of the multipath environment is regarded as indispensable for assuring reliability UHF‐RFID systems. In this paper, an ultrathin microwave absorber is described as a technology for improving the multipath environment for UHF‐RFID system. Additionally, provision is made for transparency of this absorber, because microwave absorbers should not increase the blind area of the observation camera in the region in which the UHF‐RFID system is used (around the entrance gate of offices or warehouses). Verification of tag identification probability improvement with this absorber in an actual warehouse is also presented.