| Frequency-modulated continuous-wave(FMCW)radar has simple and compact structure,and the peak emission power is low.Single-channel radar system has only one reception channel,and each element is connected to the reception channel by a radio frequency(RF)switch.The cost and complexity of the radar system can be further reduced by combining the single-channel radar system with the FMCW.In this paper,the detection of the distance,relative speed and azimuth of the near target by the single-channel FMCW radar system is studied using digital beam forming(DBF)technology.The main work is as follows:Firstly,a series-fed micro-strip antenna array working at 10.3GHz is designed as radar transceiver antenna.The side lobe level of the antenna is optimized by Taylor weighting method.The measurement results show that the-10 dB bandwidth of the antenna array is 120MHz;the gain is 15.91dB;the E-plane half power beam width is 6°,and the first side lobe level is-17.15 dB.Secondly,the velocity-azimuth coupling problem of the single-channel radar system and the solution are studied.Based on the analysis of the phase difference between each two adjacent antenna elements,a method to measure the azimuth by compensating the phase difference caused by velocity is proposed.This method has solved the azimuth ambiguity problem of single-channel radar.Finally,the signal processing flow of single-channel FMCW radar is optimized.By combining the DBF algorithm with the principle of triangular wave radar,the signal processing flow of single-channel FMCW radar is optimized to reduce the calculation amount,and its feasibility is verified by simulation of single target.A prototype of the single-channel FMCW radar has been manufactured and used to detect an actual target in outdoors,and the distance-azimuth spectrum before and after velocity compensation is given.The experimental results show that the target can be effectively detected using the proposed signal processing flow. |
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