To provide a communication device capable of preventing, multi-pass by receiving radio waves from ETC on-board units located in a communication area while blocking radio waves from ETC on-board units located outside the communication area.SOLUTION: A communication device 100 includes a radome 200 and an antenna 310. The radome 200 has a first transmissive layer 210 and a second transmissive layer 220, and a dielectric layer 230. The first transmissive layer 210 is positioned at a surface of the dielectric layer 230 and allows electromagnetic waves whose frequency is a transmission frequency to be transmitted as a first layer transmitted wave but does not transmit electromagnetic waves whose frequency is different from the transmitted frequency. The second transmissive layer 220 is positioned at a rear side of the dielectric layer 230 and transmits the first layer transmitted wave as the second layer transmitted wave when an angle of incidence of the first layer transmitted wave on the first transmissive layer 210 falls within the second layer transmission range but does not transmit through the first transmissive layer when the angle of incidence on the first transmissive layer 210 is out of the transmission range of the second layer.SELECTED DRAWING: Figure 1
【課題】通信領域外に位置するETC車載器からの電波を通さず、通信領域内に位置するETC車載器からの電波を受信することにより、マルチパスを防ぎたい。【解決手段】通信装置100は、レドーム200と、アンテナ310とを備える。レドーム200は、第1透過層210と、第2透過層220と、誘電体層230とを有する。第1透過層210は、誘電体層230の表面に位置し、周波数が透過周波数である電磁波を第1層透過波として透過させ、かつ、周波数が透過周波数とは異なる電磁波を透過させない。第2透過層220は、誘電体層230の裏面に位置し、第1層透過波の第1透過層210への入射角が第2層透過範囲内に収まる場合に第1層透過波を第2層透過波として透過させ、かつ、第1透過層210への入射角が第2層透過範囲内に収まらない場合に第1層透過波を透過させない。【選択図】図1
COMMUNICATION DEVICE, AND ELECTRONIC TOLL COLLECTION SYSTEM
通信装置、及び、電子料金収受システム
28.10.2021
Patent
Elektronische Ressource
Japanisch
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