中文摘要：

低旁瓣MIMO雷达发射方向图可以在保证主瓣发射能量的前提下，抑制旁瓣杂波和虚假目标能量，从而达到提升回波信噪比的目的。该文提出一种低旁瓣MIMO雷达发射方向图设计方法，通过对已有发射信号协方差矩阵的非对角线元素进行修正来实现低旁瓣方向图的优化设计。首先，利用方向图匹配设计方法得到具有期望主瓣形状的发射方向图，并以其作为初始值；其次，以最小化峰值旁瓣或积分旁瓣为目标函数，在约束修正后的信号协方差矩阵为半正定矩阵的前提下，利用修正矩阵的Frobenius范数为量度约束主瓣形状失真程度。上述两个优化问题都是凸优化问题，可以求得全局最优解。仿真结果表明，该方法可以得到具有期望主瓣形状和低旁瓣特性的方向图。

英文摘要：

Low sidelobe transmit pattern of MIMO radar can concentrate majority energy in the mainlobe region to improve the target detection, and reduce the energy of clutter and false targets from sidelobe, so as to enhance the SNR of echo. Based on a modified non-diagonal elements of transmit signal covariance matrix, a low sidelobe transmit pattern optimization algorithm for MIMO radar is proposed. Firstly, the pattern matching design method is implemented to obtain the desired mainlobe shape of transmit pattern, with the results as the initial value. Secondly, the cost function can be formulated as the minimization of peak-sidelobe or integrated-sideloble; the mainlobe shape distortion can be constrained by the Frobenius norm of modification matrix, and the modified transmit signal covariance matrix needs to be positive semi-definite. Since the two optimization problems are convex, the global optima can be acquired. The simulation results show that the desired mainlobe shape and low sidelobe pattern can be obtaibed with the proposed method.