本文選題：屏蔽效能 + 混波室　； 參考：《東南大學(xué)》2016年碩士論文

【摘要】：本文依據(jù)IEEE STD 299.1-2013使用嵌套混波室測(cè)試小型機(jī)箱屏蔽效能的方法,對(duì)IEEE STD299.1-2013標(biāo)準(zhǔn)中未能明確的某些方面進(jìn)行研究。使用嵌套混波室測(cè)試小型機(jī)箱屏蔽效能的方法已經(jīng)成為主流的測(cè)試方法。由于混波室以及小型機(jī)箱內(nèi)部的電磁場(chǎng)為統(tǒng)計(jì)性均勻場(chǎng),故在測(cè)試小型機(jī)箱屏蔽效能的時(shí)候,機(jī)箱內(nèi)部的電磁場(chǎng)會(huì)影響屏蔽效能測(cè)試結(jié)果,本文分析了頻率攪拌方法以及聯(lián)合攪拌方法測(cè)試小型機(jī)箱屏蔽效能的重復(fù)性問(wèn)題,以及研究了混波室法測(cè)試小型機(jī)箱的置信區(qū)間和不確定度。實(shí)驗(yàn)發(fā)現(xiàn),在攪拌帶寬為100 MHz時(shí),使用聯(lián)合攪拌的采樣次數(shù)至少為3次,才能夠使得測(cè)試的置信區(qū)間小于3 dB。除此之外,小型機(jī)箱內(nèi)部接收天線為單極子天線,針對(duì)單極子天線阻抗匹配不良好的情況,利用小型寬頻帶的微帶天線測(cè)試小型機(jī)箱的屏蔽效能,實(shí)驗(yàn)發(fā)現(xiàn),使用單極子天線測(cè)試小型機(jī)箱屏蔽效能的結(jié)果與使用小型寬帶微帶天線測(cè)試機(jī)箱的屏蔽效能的結(jié)果相一致,說(shuō)明單極子天線較大的反射系數(shù)對(duì)測(cè)試小型機(jī)箱屏蔽效能沒(méi)有影響;同時(shí),提出使用網(wǎng)絡(luò)分析儀的時(shí)域功能測(cè)試小型機(jī)箱的屏蔽效能,利用時(shí)域法測(cè)試小型機(jī)箱屏蔽效能驗(yàn)證嵌套混波室測(cè)試小型機(jī)箱屏蔽效能的準(zhǔn)確性,也提供測(cè)試非均勻場(chǎng)分布機(jī)箱屏蔽效能的一種方法。不僅如此,為了討論腔體壁面對(duì)機(jī)箱屏蔽效能測(cè)試的影響,本文從理論上推導(dǎo)了機(jī)箱內(nèi)部靠近機(jī)箱金屬壁面的接收天線所接收到的功率,通過(guò)實(shí)驗(yàn),比較了接收天線距離壁面較近時(shí)所測(cè)機(jī)箱屏蔽效能與理論計(jì)算結(jié)果之間的關(guān)系,當(dāng)在單極子與腔體壁面的距離為O.15λ的時(shí)候,嵌套混波室法測(cè)試屏蔽效能比理想情況下測(cè)試小型機(jī)箱屏蔽效能大3 dB左右。最后,當(dāng)小型機(jī)箱內(nèi)部含有加載物體的時(shí)候,研究加載物體對(duì)測(cè)試小型機(jī)箱屏蔽效能的影響,研究加載物體對(duì)機(jī)箱內(nèi)部場(chǎng)分布造成的影響；實(shí)驗(yàn)發(fā)現(xiàn),當(dāng)機(jī)箱的Q值大于Q值限值的5倍時(shí),機(jī)箱內(nèi)部的電磁場(chǎng)的場(chǎng)分布仍為瑞利分布。
[Abstract]:Based on IEEE STD 299.1-2013 method of testing shielding effectiveness of small chassis using nested mixing chamber, this paper studies some aspects of IEEE STD299.1-2013 standard which are not clear. The method of using nested mixing chamber to test the shielding efficiency of small chassis has become the mainstream test method. Because the electromagnetic field in the mixing chamber and the small chassis is a statistical uniform field, the electromagnetic field inside the box will affect the shielding effectiveness test results when testing the shielding effectiveness of the small chassis. In this paper, the repeatability of the frequency mixing method and the combined mixing method for testing the shielding effectiveness of small chassis is analyzed, and the confidence interval and uncertainty of the mixing chamber method for testing the small chassis are studied. The experimental results show that when the mixing bandwidth is 100MHz, the sampling frequency of the joint mixing is at least 3 times, so that the confidence interval of the test can be less than 3 dB. In addition, the inner receiving antenna of the small chassis is a monopole antenna. In view of the unfavorable impedance matching of the monopole antenna, the shielding efficiency of the small chassis is tested by using the small broadband microstrip antenna, and the experimental results show that, The results of using monopole antenna to test the shielding efficiency of small chassis are consistent with those of using small wideband microstrip antenna, which shows that the large reflection coefficient of monopole antenna has no effect on the shielding efficiency of small chassis. At the same time, the time domain function of the network analyzer is used to test the shielding effectiveness of the small chassis, and the accuracy of the nested mixing chamber to test the shielding effectiveness of the small case is verified by using the time domain method. A method for testing shielding effectiveness of non-uniform field distribution chassis is also provided. Moreover, in order to discuss the influence of the cavity wall on the shielding effectiveness test of the chassis, this paper theoretically derives the power received by the receiving antenna near the metal wall of the chassis. The relation between the shielding efficiency of the chassis measured when the receiving antenna is close to the wall is compared with the theoretical results. When the distance between the monopole and the cavity wall is 0. 15 位, The shielding effectiveness of the nested mixing chamber is about 3 dB higher than that of the ideal test of small chassis. Finally, when there is a loading object in the small chassis, the effect of the loading object on the shielding effectiveness of the small chassis is studied, and the effect of the loading object on the distribution of the field inside the chassis is studied. When the Q value of the chassis is more than 5 times the limit value of the Q value, the field distribution of the electromagnetic field in the chassis is still Rayleigh distribution.
【學(xué)位授予單位】：東南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TN03

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本文編號(hào)：2112535