Pulse compression technology is very useful in modern radar system, with the reason that it can solve the contradiction between the radar range and range resolution. Now, nonlinear frequency modulation (NLFM) is researched widely, because the pulse compression of the NLFM signal can lower the range sidelobe better than À40 dB without window weighting. But in some applications, the reducing level also cannot meet the requirements. This paper put forward a continuous nonlinear FM waveform designed bring down the level of the range sidelobe, which can suppress the range sidelobe to À86 dB. Therefore, it can be used in many radar systems, especially in some kind of weather radar.
Keywords Pulse compression • NLFM • Continuous nonlinear FM waveform design
IntroductionIn radar system, in order to increase the operating distance as far as possible, we should transmit wide pulse, but the biggest disadvantage of this is that wide pulse will result in the decline of the range resolution. So in order to compromise this contradiction, pulse compression is brought in.Nowadays, linear frequency modulation (LFM) signal and nonlinear frequency modulation (NLFM) signal are widely used in pulse compression. Although LFM is easy to generate, the output of the pulse compression is unsatisfactory. So in order to decrease the sidelobe of the signal, windowing weighting is essential, but which will result in the loss of signal-to-noise ratio and the main lobe of the signal will also be widen. So researchers want to find other signal to improve this problem. NLFM has the ability that it needn't weighting, and the result of the pulse compression is very good. Because of no window weighting, so it will not result in the