An Fmcw Millimeter Wave Radar System If Circuits And Signal Processing Research

In recent years, with the rapid development of the millimeter-wave radar technology and the demand of the safety, anticollision radar system is being studied and used widely. The IF(intermediate frequency) circuit and the digital signal processing are two important parts of it. In this paper, the IF circuit, the processor based on the pulse count technology and the adaptive signal processing of the system are discussed thoroughly. Major contents are abstracted as follows:1 The evolved .history of the anticollision radar system is given curtly. The development of the signal processing of the radar and the application of the digital signal processing technology to the radar system is summarized.2 The FMCW millimeter-wave radar system is introduced. The basic parts of the system and its work principle, as well as the index of it, are discussed in detail. The SAE-100 millimeter-wave anticollision radar system and the anticollision radar used in the industry are also introduced curtly.3 The realization of the IF circuit of the FMCW millimeter-wave radar is discussed thoroughly. The major contents of this part is composed of the basic principle of the IF circuit, the affection of the noise performance of the preamplifier to the whole system, the main constitutes of the receiver and their test results and the modulation circuit of the VCO, etc. The test result shows that the performance of these circuits is fairly good.4 The leaked triangular wave of FMCW millimeter-wave radar has been analyzed. Transmitter signal leak of the FMCW radar system is a serious problem that puzzles people for a long time. According to its influence on the whole system based on the experiment, theory analysis is given to verify the reason of it's coming, and. Several methods to restrain the leaked signal are also given. It is a good reference for the FMCW millimeter-wave radar system design.5 In order to improve the system performances and simplify the IF circuit, a new scheme is given, which based on the frequency domain dynamic compression method. It can restrain the strong interference signal-leaked triangular wave and is able tosubstitute the AGC to some extent. The realization and the result of it are also given.6 Another important part of this paper is the adaptive signal processing of the FMCW millimeter-wave radar system. The adaptive signal processing technology is a rising science embranchment, which composed with many subjects and fields. In this paper, application of the adaptive filter to elimination of the leaked triangular wave and the adaptive signal processing of the FMCW millimeter-wave radar system is studied thoroughly. The use of an adaptive filter offers an attractive solution to the problem as it usually provides a significant improvement in performance over the use of the conventional methods.7 In order to improvement the performance of the whole system and reduce the cost, a new signal processor is given, which based on the new pulse count method brought forward by the author. An adaptive demodulation circuit is also given to reduce the affection of the noise, the interference and the instability of the signal.