US Patent 10972308 Communication device and automobile including the same

A communication device includes a master station, a ring-type transmission line whose start point and end point are connected to the master station, and a plurality of slave stations connected to the ring-type transmission line in parallel. The master station transmits a signal and feeds electric power from both of the start point and the end point of the ring-type transmission line. Each of the slave stations includes an impedance variable element connected to the ring-type transmission line in parallel, and values are set to the impedance variable elements in accordance with the connection positions of the slave stations.