对数频偏FDA方向图解耦优化

Decoupling optimization of frequency diverse array with logarithmically increasing frequency offset

针对对数频偏频率分集阵列(frequency diverse array,FDA)中存在的频率偏移量取值固定、主瓣扫描精度较低的问题,并行地提出两种对数频偏频率分集阵列方向图解耦的优化方法。首先,将均匀线性阵列替换为采用正弦频偏增量的交叉子阵结构,在此基础上将频偏增量选择问题转化为二维空间的最优化问题,通过改进的粒子群算法解算最优频偏增量实现方向图解耦优化。此外,将通信中的格雷码编码方式应用于FDA阵列的频偏编码中,提出基于发射端格雷码频偏编码方式的发射方向图解耦方法。最后,仿真验证了两种优化方法的有效性。

This paper aims at the problem that the frequency offset of the frequency diverse array(FDA)with logarithmically increasing frequency offset(log-FDA)is fixed,the mainlobe’s scanning precision is low.Two decoupling optimization methods of log-FDA is proposed.Firstly,the uniform linear array is replaced by the cross subarray architecture with sinusoidal frequency offset.On this basis,we transforme the frequency offset incremental selection problem into the optimization problem of two-dimensional space.In order to realize the beampattern decoupling optimization,we solve the optimal frequency offset increment by improved particle swarm optimization algorithm.Then,the Gray code coding method used in communication is applied to the frequency offset coding of the FDA array.A transmit beampattern decoupling method based on the Gray code frequency offset coding method at the transmitting end is proposed.Finally,simulations verify the effectiveness of the proposed method.