射频电路中等功率增益圆的绘画，本程序设置的增益为最大可能增益的90％，80 ，50％，利用等功率圆可分别设计匹配网络。-Drawing Equal Power Gain Circuit in radio-frequency circuit ,in this program,the gain was set as 90％，80 ，50％ of the greatest possibility of gain,besides, the Equal Power Gain　Circuit can help design matching network.