Patent ID: 7167008

Claim:
A microwave sensor for transmitting a plurality of microwaves of different frequencies toward a detection area and carrying out an object detection operation based on reflected waves of the microwaves from an object present in the detection area, the microwave sensor comprising: a distance identification means for obtaining a relative distance to the object present in the detection area based on the reflected waves; a movement-distance identification means for obtaining a movement distance per unit of time of the object present in the detection area; and an object determination means for receiving output from the distance identification means and the movement-distance identification means, and carrying out an operation for object detection by setting a movement distance value per unit of time threshold which is a threshold for determining object detection, to a first value corresponding to a movement distance that is very unlikely to occur by plants moving due to wind when the relative distance to the object present in the detection area is less than a predetermined value and by setting the movement distance value per unit of time threshold to a second value smaller than the first value when the relative distance is the predetermined value or greater.