我国目前生产的特征频率f_T在1千兆以上的高频晶体管,其功率数量级大都不超过几瓦,要制造几十瓦的发射机,必须用多管合成,简单的并联使用是不行的.一是因为同一型号的晶体管的离散性较大,不能保证均匀负担,二是因为许多管子并联时,其输出阻抗太小,难以与负载取得匹配,所以唯一正确的途径是采用功率合成法. At present, China's production of high-frequency transistors with the characteristic frequency f_T above 1 gigaoh is not more than a few watts at most in order of magnitude. To manufacture tens of watt transmitters, it is necessary to use multiple tubes to synthesize and simply use them in parallel is not acceptable. Because the same type of transistor dispersion is large, can not guarantee a uniform load, and second, because many tubes in parallel, the output impedance is too small, it is difficult to match with the load, so the only correct way is to use power synthesis.