本文選題：多模單脈沖跟蹤　切入點：緊湊型自跟蹤饋源　出處：《電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：當代衛(wèi)星通信業(yè)務的發(fā)展向地面站天線提出了多頻復用、可移動化以及可跟蹤等需求。隨著Ka頻段及更高頻段的開發(fā)日趨完善,將這些頻段與傳統通信頻段結合的多頻段天線可充分地利用衛(wèi)星通信頻譜資源并降低地面站成本。在移動衛(wèi)星通信的業(yè)務中,可跟蹤的小型化緊湊型天線成為研究熱點。而多頻段和自跟蹤饋源的研發(fā)往往是讓衛(wèi)星通信天線滿足這些需求的關鍵。本文以此為出發(fā)點,設計并仿真了Ku頻段線極化緊湊型單脈沖饋源、Ku/K雙頻單脈沖饋源以及X/Ku/Ka三頻收發(fā)共用饋源。首先,為解決多模單脈沖饋源在線極化跟蹤中縱向結構冗長的問題,設計了基于同軸波導的緊湊型半長度TE21模耦合器。該耦合器在保持傳統圓波導TE21模耦合器對TE21模耦合以及對其它模式隔離性能的同時,將縱向長度縮減了一半。然后利用同軸波導TE21模與內圓波導TE11模分別傳輸差模信號與和模、發(fā)射信號。再通過軸向扼流環(huán)與介質桿的設計,構成了具有和差波束與發(fā)射功能的Ku頻段線極化自跟蹤饋源。由于采用了半長度TE21模耦合器,該饋源縱向結構緊湊。饋源接收和波束與發(fā)射波束旋轉對稱性能良好,結合差波束可實現單脈沖跟蹤。其次設計了Ku/K雙頻單脈沖饋源以實現多頻段自跟蹤。在Ku頻段上利用同軸波導的TE11和TE21模形成雙模單脈沖機制進行線極化自跟蹤,而在K頻段上利用內圓波導TE11和TM01模形成雙模單脈沖機制進行圓極化自跟蹤。該饋源在兩個頻段上都具有高等化度的和模波束以及具有軸向零深的差模波束,因此可在兩個頻段上測量天線增益最大指向與衛(wèi)星位置的偏差。最后提出了一種X/Ku/Ka三頻收發(fā)共用饋源方案。X頻段的收發(fā)雙圓極化波先由方波導金屬隔板圓極化器形成,再通過矩形波導臂耦合入X/Ku公共同軸波導；Ku頻段對同軸波導TE11模收發(fā)雙線極化饋電由矩形波導開縫耦合完成,并經階梯變徑段過渡到X/Ku公共同軸波導；Ka頻段的內圓波導收發(fā)雙圓極化饋電則通過正交模耦合器和雙頻螺釘圓極化器完成。X和Ku頻段的收發(fā)波束由軸向波紋喇叭形成,而Ka頻段的收發(fā)波束由介質桿形成。該三頻段饋源具有穩(wěn)定的邊緣照射電平,可最大限度地擴展衛(wèi)星通信天線工作頻帶。
[Abstract]:With the development of satellite communication service, the requirements of multi-frequency multiplexing, removability and traceability have been put forward to earth station antenna. With the development of Ka band and higher frequency band, the development of Ka-band and higher frequency band is becoming more and more perfect. The multiband antenna which combines these bands with the traditional communication band can make full use of the spectrum resources of satellite communication and reduce the cost of earth station. Miniaturized compact antenna with traceability has become a research hotspot, and the research and development of multi-frequency band and self-tracking feed are often the key to satisfy these needs of satellite communication antenna. In order to solve the problem of long longitudinal structure in on-line polarization tracking of multi-mode monopulse feed, we design and simulate the Ku-K dual-frequency monopulse feed and the X / Kur / Ka three-frequency transceiver common feed in Ku band. A compact half-length TE21 mode coupler based on coaxial waveguide is designed, which keeps the traditional circular waveguide TE21 mode coupler from TE21 mode coupling and other modes isolation performance. The longitudinal length is reduced by half. Then the differential mode signal and sum mode are transmitted by using the coaxial waveguide TE21 mode and the inner circular waveguide TE11 mode, respectively. A Ku band line-polarization self-tracking feed with sum difference beam and transmitting function is constructed. Because of the use of half-length TE21 mode coupler, the feed has compact longitudinal structure, and the feed receiving and beam-beam rotating symmetry performance are good. Single pulse tracking can be realized by combining differential beam. Secondly, Ku/K dual-frequency monopulse feed is designed to realize multi-band self-tracking. Linear polarization self-tracking is carried out by using TE11 and TE21 modes of coaxial waveguide to form dual-mode monopulse mechanism in Ku band. On the other hand, the circular polarization self-tracking is carried out by using the dual-mode monopulse mechanism formed by the internal circular waveguide TE11 and TM01 modes in the K band. The feed has a high sum mode beam in both bands and a differential mode beam with axial zero depth. Therefore, it is possible to measure the deviation between the maximum antenna gain direction and the satellite position in two frequency bands. Finally, an X / Ku-K / Ka three-band common feed scheme .X band dual-circular polarization wave is first formed by a square waveguide metal partition circular polarizer. Then the rectangular waveguide arm is coupled to the X / Ku common coaxial waveguide / Ku frequency band to receive and receive dual-line polarization feed of the TE11 mode of the coaxial waveguide, which is accomplished by the rectangular waveguide slit coupling. And the internal circular waveguide transmitting and receiving double circular polarization feed through the step variable diameter section to the X / Ku common coaxial waveguide / Ka band is formed by the axial corrugated horn through the quadrature mode coupler and double frequency screw circular polarizer. The Ka-band beam is formed by a dielectric rod, and the three-band feed has a stable edge radiation level, which can maximize the operational band of the satellite communication antenna.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN927.2

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本文編號：1595893