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一、问题的提出近几年来,天线工程师们关心下列几个问题: (1)据国内外文献报导,大型反射面天线的效率已达到90%左右,中小型天线效率达到70%左右。这是否达到理论极限值? (2)天线效率的理论计算值与实测值之差为(0.1～0.2)分贝,用什么办法鉴定? (3)随着计算机的发展和天线自动化测试技术的提高,人们想借助计算机计算天线性能代替天线外场测量,从而可以缩短研制周期和减少试验费用。这对大型天线的研制非常需要。 (4)微波天线增益测量方法主要有:绝对法、比较法(包括二次比较法)、射电星法、散射场积分法、次级方向图积分法、测量输出端功率法等。这些方法对同一天线进行测量,其结果并不一定相同,哪种方法精确度高?比较法测增益能否达到±0.2分贝(或更高)的测试精度?
First, the issue raised In recent years, antenna engineers are concerned about the following questions: (1) According to domestic and foreign literature, the efficiency of large reflector antenna has reached 90%, small and medium sized antenna efficiency of about 70%. Is this the theoretical limit? (2) The difference between the theoretical and measured values of the antenna efficiency is (0.1-0.2) dB, and what method is used? (3) With the development of the computer and the improvement of the antenna automatic testing technology, People want to use the computer to calculate the antenna performance instead of antenna field measurements, which can shorten the development cycle and reduce test costs. This is very necessary for the development of large antennas. (4) Microwave antenna gain measurement methods are: absolute method, comparison method (including the second comparison method), radio star method, scattering field integration method, secondary pattern integration method, the output power measurement method. These methods of measurement of the same antenna, the results are not necessarily the same, which method of high accuracy? Comparison of the law to measure the gain can reach ± 0.2 dB (or higher) test accuracy?