| 摘要 |
A continuous wave Doppler radar system having a transmitter module and a receiver module is provided for automotive vehicles. Each module includes an antenna system, including a horn, a lens, and a waveguide system, which is attached to a monolithic microwave integrated circuit (MMIC) chip that provides all necessary electronic functions. Each MMIC chip may be attached to a metal base heat sink, which may be conveniently connected to a base plate heat sink that holds the entire radar assembly. The transmitter module includes a voltage controlled oscillator (VCO) that generates a VCO frequency signal which is amplified and switched sequentially to three multiplier chains for transmission in three different directions. Each transmit signal is taken off the MMIC chip by a dielectric waveguide and directed to the antenna system. The receiver module includes three receivers that are selected sequentially to provide a beam azimuth scanning function. A reference local oscillator is provided at the VCO frequency by electromagnetic radiative coupling from the VCO of the transmitter module. Information on the location and relative speed of a radar target are obtained by comparing the frequency of the signal reflected by the target with the frequency of the signal radiated by the transmitter module. Quadrature mixers are used for each receiver channel to output low frequency data signals containing amplitude and phase information on the received reflected signal. Radar directional discrimination is achieved by sequential selection of the mixer output signals.
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