说明：  极坐标下的分贝画图。matlab中极坐标画图函数为polar，但是无法画出转化为dB的图形，此函数为画db为单位数据的极坐标图形。
(Db drawing in polar coordinates . matlab polar coordinate drawing functions for the polar , but can not draw dB graphics , this function graphics for painting db data in polar coordinates .)