Novel nonlinear phase distortion estimation in wideband linear frequency modulated waveform

摘要

Recently, frequency modulated continuous wave (FMCW) technique has drawn a lot of attention in various applications where the high resolution performance is needed due to its cost-eectiveness and low complexity as well as the high resolution performance. One of degradation factors in the technique is the characteristics of nonlinear phase distortion in transmitted waveform. The phase distortion degrades the resolution performance, that is, the contrast and resolution of the obtained range prole or image can be degraded. Especially, as the system with FMCW technique requires higher resolution performance and longer range coverage, the degradation problem becomes more severe hence it can be limited to be utilized for long-range applications like synthetic aperture radar (SAR). This paper proposes the novel algorithms to estimate the nonlinear phase distortion without any expensive devices but only one reference delay line and provides a favorable condition for parallel processing in the algorithms. The estimate of the distortion can be utilized for designing predistortion to compensate it. Simulation result obtained with an arbitrarily generated nonlinear phase distortion, demonstrates that the proposed scheme has outstanding estimation performance.