Abstract: An array antenna radar apparatus has a single front end shared by a plurality of antennas, a first switch for cyclically connecting the antennas to the front end at a prescribed switching frequency, and a second switch for cyclically connecting the output of the front end to frequency converters corresponding to the antennas. The frequency converters frequency-convert intermediate-frequency signals of the respective antennas output by the front end to baseband signals at the switching frequency. Phase shifters and amplitude adjusting units apply a phase shift or amplitude adjustment to the outputs of the frequency converters and combine the resulting signals, thereby making it possible to detect a target in a desired direction.

Abstract: A FM-CW radar device is provided for frequency-modulating a high frequency signal with a modulation signal, transmitting the modulated high frequency signal, receiving a signal reflected by a target object and frequency-modulating the reflection signal with a signal generated by a local oscillator signal source provided by branching a portion of the transmitting signal. A modulator is disposed between a radar transmitting section and a transmitting antenna. The modulator modulates the transmitting signal with a second frequency which is far lower than the radar transmitting frequency and twice as much as the sum or the difference of a Doppler frequency generated by a relative propagation velocity and a beat frequency generated by a propagation delay time. A first frequency converter frequency modulates the received signal reflected by the target object with the local oscillator.