| 摘要 |
<p>PURPOSE:To precisely detect a target without being influenced by the radar wave from another device in a radar device for automobile for detecting the target in the outside of a vehicle. CONSTITUTION:In a radar device for transmitting and receiving radar waves different in turning direction through a two-terminal driving type circularly polarizing antenna 12 by using a hybrid circuit 22, and detecting an obstruction in front of a vehicle, transmission and receipt of radar waves are conducted in the state where the phase of a phase shifter 24 is set to 0 deg.. When the receive level of radar waves is sharply changed, or the receive level is an obstruction judging level or more, the phase of the phase shifter 24 is changed to 180 deg. to reverse the turning direction of the transmitted/received radar waves, and when the received level is the obstruction judging level or more in this state, the presence of the obstruction in front of the vehicle is judged, and an alarm is issued. Consequently, the obstruction present in front of the vehicle can be precisely detected without being influenced by the radar wave transmitted from the same kind of a radar device.</p> |
