设计一矩形栅格的相控阵天线方向图及其仿真；其中包含两个文件（分别是main_antenna_gain和 antenna_gain）,其中antenna是调用函数，主要计算方向图增益(Design of a rectangular grid phased array antenna pattern and its simulation; which contains two files (respectively main_antenna_gain and antenna_gain), where antenna is the call function, the main calculation of the direction of the gain)