最近,美帝国际商业机器公司制成了14～18千兆赫的实验性晶体管放大器和振荡器。由于采用了砷化镓晶体管,使它们的频率特性提高了。在室温下,砷化镓晶体管中的电子饱和漂移速度比在硅中大2倍。据报道,在17千兆赫下,振荡器输出为1毫瓦。在14.9千兆赫、150千兆赫的3分贝带宽下,四级窄带放大器产生最大的功率增益为16分贝。在18千兆赫、380兆赫的带宽以上,三级放大器呈现的最大增益为6分贝。电路中所采用的新型晶体管的外推法测量数据表明,晶体管的最高振荡频率实际上在30千兆赫以上。理论计算表明,只要 Recently, the US imperial International Business Machines Corporation made 14 to 18 gigahertz experimental transistor amplifiers and oscillators. Due to the use of gallium arsenide transistors, their frequency characteristics are improved. At room temperature, electrons in GaAs transistors drift about twice as fast as in silicon. It is reported that at 17 GHz, the oscillator output is 1 milliwatts. The four-stage narrowband amplifier produces a maximum power gain of 16 dB at 14.9 GHz and 150 GHz at 3 dB bandwidth. Above 18 GHz, 380 MHz bandwidth, the maximum gain exhibited by the three-stage amplifier is 6 dB. Extrapolation measurements of the new transistors used in the circuit indicate that the maximum oscillation frequency of the transistor is actually above 30 gigahertz. Theoretical calculations show that as long as