Antenna, radar apparatus and signal processing method

A signal processing method of deriving a position of a target by a reflection wave received with a plurality of reception antennas provided on a substrate surface of a dielectric substrate, the signal processing method comprising:

• outputting a transmission wave by an antenna including a plurality of transmission antennas and the plurality of reception antennas, with using a first transmission antenna, a third transmission antenna provided at a position shifted in a short direction of the first transmission antenna, a second transmission antenna provided at a position between the first transmission antenna and the third transmission antenna so that a portion of the second transmission antenna in a longitudinal direction is overlapped with a portion of the first and third transmission antennas in the longitudinal direction, and a fourth transmission antenna provided at a position point-symmetrical with respect to the position of the second transmission antenna, about the position of the third transmission antenna;
• receiving the reflection wave with using the plurality of reception antennas provided so that a portion of each of the reception antennas in the longitudinal direction is overlapped with a portion of the second transmission antenna in the longitudinal direction;
• deriving a position of the target in a horizontal direction with respect to a road surface, based on reflection waves of transmission waves outputted from the first transmission antenna and the third transmission antenna from the target;
• and
• deriving a height of the target in a vertical direction with respect to the road surface, based on reflection waves of transmission waves outputted from the second transmission antenna, the third transmission antenna and the fourth transmission antenna from the target.