用於閉域空間（礦井與隧道等）無線通訊系統及洩漏同軸電纜的特性研究
摘 要
洩漏同軸電纜以其良好的電波覆蓋效能在礦山、地鐵、隧道或建築物等閉域空間內的無線通訊中得到了廣泛的應用，對其電氣特性的研究日益成為研究的熱點。本文探討了礦井無線通訊的頻率特性和系統模型，提出今後技術發展的方向。以及在研究了井下地質條件和生產環境對通訊頻率的影響因素基礎上,確定了井下無線通訊傳輸的較佳頻段,並提供了井下蜂窩通訊基站的佈置方案。最後就洩漏同軸通訊電纜的既能傳輸電磁波訊號,又可發無線電磁波訊號的獨特效能進行了分析;對其特殊效能的應用進行研究.並探討其應用和發展前景.並且從洩漏同軸電纜(簡稱漏纜)的結構出發，介紹了漏纜的幾何引數和物理引數，然後由結構進行輻射原理的探討，分析了其輻射模式，並且運用柱面傅立葉變換由外導體上的開槽處的場分佈得到漏纜在自由空間的輻射場，進一步分析了存在反射的非自由空間內輻射場的求解，討論了漏纜的位置對輻射場的影響。然後，提出了洩漏同軸電纜的幾個重要的電氣特性指標，探討在設計漏纜的頻帶、駐波比、禍合損耗、傳輸衰減等重要指標時的基礎理論和相關問題，接著對漏纜的電氣特性指標進行了綜合設計。最後分別介紹了漏纜在地鐵、公路隧道、建築物等閉域空間中的具體應用，比較了天線輻射和漏纜輻射的覆蓋效能差異，提出了利用漏纜實現無線通訊
關鍵詞 洩漏電纜；無線通訊；輻射場; 頻帶; 耦合損耗;Abstract
Leak coaxial cable with good radio coverage performance in mining, the MTR, tunnels or buildings closed space within the domain of wireless communication has been widely used, its electrical characteristics of increasingly become a hot spot. This paper explores the mine wireless communication frequency and system model, the future direction of technical development. And the study of the underground geological conditions and the production environment on the frequency communications on the basis of factors, identified underground wireless communications transmission band better, and provided a cellular communications Underground station layout program. Finally leakage coaxial cable transmission of electromagnetic signals can, electromagnetic signals can launch of the unique properties of the analysis; its special properties of research. and explore its applications and development prospects. and leakage from the coaxial cable (cable leakage ) structure, introduced the cable missed the geometric parameters and physical parameters, then the structure of radiation theory, analysis of the radiation pattern and the use of Fourier transform cylindrical outer conductor from the slot on the distribution cable to be leak free space in the radiation field, further analysis of the non-existence of reflection free space within the radiation field solution discussion of the location of cable leakage of radiation field. Then, a leak of several important coaxial cable to the electrical characteristics of indicators, designed to explore the frequency leakage cable, VSWR, coupling loss, attenuation, and other important indicators of the basic theory and related issues, Then the electrical cable leakage characteristic indicators of the overall design. Finally introduced in the MTR missed cable, highway tunnels, buildings and closed space domain specific applications, Comparison of the antenna radiation and radiation leakage cable coverage performance differences, the use of leak cable wireless communication options.
Key words: leaky coaxial cable, wireless communication radiated field, frequency band, coupling loss,
第一章 緒論
1.1礦井及隧道無線通訊系統探討
40 年來, 國內外作了多次井下無線通訊試驗, 研製了部分礦井無線通訊的裝置。90 年代以後,隨著通訊技術的發展,礦井無線通訊逐漸進入實用階段。由於礦井情況複雜,理論研究相當困難,因此礦井中的無線通訊主要以實驗為基礎緩慢發展。試驗表明, 在中短波頻段, 礦井隧道對電波衰減最大, 通訊距離最近。這可以認為是隧道尺寸與波長比擬產生諧振吸收或電波在有限空間內多次反射能量消耗的結果。在超短波,通訊距離隨著頻率升高而增加,電波傳播衰減逐漸減小。這種單調的反比變化是由於隧道對更高頻率的電波漸呈波導作用引起的,因而傳播條件逐漸改善,通訊距離加大。在微波頻段,隨著頻率升高衰減變得很小,因此隧道可認為是微波通訊的波導型通道。這是由於隧道直徑遠遠大於波長,微波訊號在隧道中獲得了相對較大的自由傳播空間形成的。上述實驗表明,隧道斷面尺寸決定了截止頻率。斷面大,截止頻率低,通訊效果就好;斷面小,截止頻率高,則必須選擇更高的訊號頻率才能實現井下無線通訊。
1.2 礦井隧道無線通訊方式
礦井隧道通訊的特點是封閉於地下的區域性環境中, 與地面通訊無相互干擾, 因此可以根據需要進行開發, 但應符合通訊的發展,進行統