Abstract: An emission element enclosed inside an electrodeless lamp 5 is excited by an electromagnetic field of a microwave irradiated from a magnetron 2 for emitting light from the electrodeless lamp 5. A soft-starting method is provided such that an electric power enough to drive the magnetron 2 is gradually increased. The soft-starting method is to prevent the magnetron from being destroyed by self-heating due to a reflected wave of the microwave. The soft-staring method is used when a light begins to be emitted from the electrodeless lamp 5. Accordingly, the electrodeless lamp system is provided such that breakage of the magnetron caused by the self-heating due to the reflected wave of the microwave can be prevented.

Abstract: An emission element enclosed inside an electrodeless lamp 5 is excited by an electromagnetic field of a microwave irradiated from a magnetron 2 for emitting a light from the electrodeless lamp 5. A soft-starting method is provided such that an electric power enough to drive the magnetron 2 is gradually increased. The soft-starting method is to prevent the magnetron from being destroyed caused by a self-heating due to a reflected wave of the microwave and is used when a light begins to be emitted from the electrodeless lamp 5.

Abstract: A communication system for vehicles, which obtains exact communication processing with responders mounted on vehicles running on a road having a plurality of traffic lanes, is disclosed. An expressway has three traffic lanes. A gantry is disposed in a specified position on the expressway. On the gantry are disposed antenna units to counter the traffic lanes respectively. The antenna units are provided with communication areas by means of a pair of antenna elements respectively. The antenna element is composed of a microstrip array antenna disposed with eight pieces of patches laid out in two rows with four pieces in each row. The antenna units controls communication processing to communicate with vehicles adjoining each other. When response signals are sent from a vehicle mounted responder, the vehicle mounted responder is fixed and communication processing for toll collection is performed.