發(fā)布時間：2018-10-10 07:33

【摘要】：隨著科學(xué)技術(shù)的迅猛發(fā)展,為了滿足人們對于雷達技術(shù)要求的不斷提升,有關(guān)相控陣天線的相關(guān)技術(shù)應(yīng)運而生。相控陣天線可以通過對系統(tǒng)中各不同的天線陣元之間微波信號的相位延時的變化情況進行相應(yīng)的控制,從而實現(xiàn)波束的形成與掃描工作,因而其擁有著無物理運動轉(zhuǎn)向、波束指向范圍精準并且靈活度較高的優(yōu)點。然而目前在寬帶相控陣天線中通常會使用電移相器控制微波信號的相移,但是傳統(tǒng)的微波移相器會使信號的瞬時帶寬受到孔徑效應(yīng)的限制,從而對相控陣天線系統(tǒng)的性能產(chǎn)生影響,因此利用實時延技術(shù)實現(xiàn)相控陣天線系統(tǒng)就成為解決這一難題的有效手段之一。利用微波光子實時延技術(shù)實現(xiàn)的光控相控陣天線與傳統(tǒng)的相控陣天線系統(tǒng)相比其信號損耗較低,工作帶寬范圍大,生存能力強,保密性能也更優(yōu)秀,因此基于微波光子技術(shù)的可調(diào)光延時線已經(jīng)成為相關(guān)問題研究的熱點方向。目前已被國外廣泛報道的各類光延時線結(jié)構(gòu)主要由有普通光纖延時結(jié)構(gòu)、色散光纖真延時結(jié)構(gòu)、微環(huán)濾波器延時結(jié)構(gòu)、空間光柵延時結(jié)構(gòu)以及利用布拉格光柵和啁啾光柵等光纖光柵的延時結(jié)構(gòu),而國內(nèi)的相關(guān)研究則起步較晚,且尚在發(fā)展階段。因此本文在此基礎(chǔ)之上,設(shè)計了一種基于色散光纖棱鏡的光相控陣天線波束形成系統(tǒng),并詳細介紹了其系統(tǒng)結(jié)構(gòu)及工作原理,同時對基于色散光纖棱鏡的光延時線溫度特性進行了理論介紹與分析。這一結(jié)構(gòu)的光相控陣天線對于光纖切割精度的要求較低,同時系統(tǒng)中采用的光學(xué)元件及各類器件的數(shù)目較少,避免了光開關(guān)的使用,能夠在顯著降低成本的同時極大的提升系統(tǒng)工作精度和工作性能。為了對基于色散光纖棱鏡的光相控陣天線系統(tǒng)波束成系統(tǒng)的性能與可行性進行具體分析,我們對系統(tǒng)的各項參數(shù)進行了計算并使用了Optisystem軟件對系統(tǒng)鏈路進行仿真設(shè)計,同時通過使用MATLAB軟件對系統(tǒng)的波束指向角度進行計算,驗證了根據(jù)相應(yīng)的系統(tǒng)參數(shù)設(shè)計,Ka頻段下的基于色散光纖棱鏡的光相控陣天線系統(tǒng)可以±30°的波束指向范圍內(nèi)穩(wěn)定工作,同時得到了由于1nm的波長抖動所引起的波束指向角度偏移大約為1.92°。最后在實驗部分,我們簡單介紹了在實驗中使用的矢量網(wǎng)絡(luò)分析儀的工作原理以及系統(tǒng)誤差校準的相關(guān)知識。并通過使用矢量網(wǎng)絡(luò)分析儀對不同光纖信道中傳輸信號的相位-頻率曲線進行測試,并進行了相關(guān)計算,從而對溫度變化對于光相控陣天線系統(tǒng)波束指向合成的影響進行了實驗研究,最終可以得到由于1℃的溫度變化所引起的不同通道間延時差值最大為0.63ps,并且在Ka頻段下可以通過調(diào)相設(shè)置一個中心溫度使基于色散光纖棱鏡的光相控陣天線系統(tǒng)可以在波束指向偏移±3.5°的允許范圍內(nèi),在±7.5℃的溫度范圍內(nèi)正常工作。
[Abstract]:With the rapid development of science and technology, in order to meet the requirements of radar technology, the related technology of phased array antenna came into being. The phased array antenna can control the change of phase delay of microwave signal between different antenna elements in the system, thus the beamforming and scanning can be realized, so that the antenna has no physical motion steering. The advantages of accurate beam pointing range and high flexibility. However, in the wideband phased array antenna, the electric phase shifter is usually used to control the phase shift of the microwave signal, but the traditional microwave phase shifter will limit the instantaneous bandwidth of the signal by the aperture effect. As a result, the performance of phased array antenna system is affected, so the realization of phased array antenna system using real-time continuation technology has become one of the effective methods to solve this problem. Compared with the traditional phased array antenna system, the optical phased array antenna realized by microwave photonic real-time continuation technology has lower signal loss, wider working bandwidth, stronger survivability and better security performance. Therefore, the tunable optical delay line based on microwave photon technology has become a hot research topic. At present, all kinds of optical delay line structures that have been widely reported abroad are mainly composed of common fiber delay structure, dispersion fiber true delay structure and microloop filter delay structure. The space grating delay structure and the fiber Bragg grating and chirped grating delay structure are used, but the related research in China is late and still in the stage of development. On the basis of this, a kind of optical phased array antenna beamforming system based on dispersive fiber prism is designed, and its system structure and working principle are introduced in detail. At the same time, the temperature characteristics of optical delay line based on dispersive fiber prism are introduced and analyzed theoretically. The optical phased array antenna with this structure requires less precision of optical fiber cutting, and the number of optical elements and all kinds of devices used in the system is less, thus avoiding the use of optical switches. It can greatly improve the system working precision and performance while significantly reducing the cost. In order to analyze the performance and feasibility of the beamforming system of optical phased array antenna system based on dispersive fiber prism, we calculate the parameters of the system and use Optisystem software to simulate the system link. At the same time, by using MATLAB software to calculate the beam-pointing angle of the system, it is verified that the optical phased array antenna system based on dispersive fiber prism can work stably in 鹵30 擄beam-pointing range according to the corresponding system parameters. At the same time, the beam-pointing angle offset caused by the wavelength jitter of 1nm is about 1.92 擄. Finally, in the experimental part, we briefly introduce the working principle of the vector network analyzer used in the experiment and the related knowledge of system error calibration. The phase-frequency curves of the transmitted signals in different fiber channels are tested by using a vector network analyzer, and the correlation calculation is carried out. The effect of temperature change on beam direction synthesis of optical phased array antenna system is studied experimentally. Finally, the maximum delay difference between different channels caused by temperature variation at 1 鈩，

本文編號：2261173