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三十年代末,欧洲大陆战云密布。为了防范纳粹德国的空袭,英国在沿海地带设置了许多雷达站。这些雷达采用的是三极管,发射波长约为10米的电磁波束,在广阔无垠的天空中搜寻那些不速之客。在战争初期的防空作战中,三极管功绩卓著备受赞赏。可是后来,对于潜艇,三极管雷达便茫然无措了。潜艇游弋于水下,只把小巧的潜望镜伸出水面。为了探测潜望镜一类的小型目标,雷达的波长应在10厘米左右。三极管工作频率的提高,遇到了一些根本上的限制。那时,三极管的最高频率仅为100兆赫,可产生波长为3米的电磁波。德国潜艇来去无踪、神出鬼没,成
The late thirties, the European mainland clouds. In order to prevent Nazi Germany's air strikes, the United Kingdom set up a number of radar stations in the coastal zone. These radars use triodes to emit electromagnetic beams at about 10 meters of wavelength, searching for those uninvited guests in the boundless sky. In the early war air defense operations, the transistor has been highly appreciated. But then, the submarine, transistor radar will be at a loss. Submarine cruising in the water, only the small periscope out of the water. In order to detect small targets such as periscope, the wavelength of the radar should be about 10 centimeters. Transistor work frequency, met some of the fundamental limitations. At that time, the maximum frequency of the transistor was only 100 MHz, which produced electromagnetic waves with a wavelength of 3 meters. German submarine come and go without trace, come out of nothing, into