本文選題：W波段 + 被動(dòng)成像��； 參考：《電子科技大學(xué)》2016年博士論文

【摘要】：自然界中所有物體都以電磁波的形式向外產(chǎn)生熱輻射,發(fā)射率不同的物體的輻射強(qiáng)度不相同。被動(dòng)毫米波成像技術(shù)利用毫米波輻射計(jì)接收目標(biāo)的電磁輻射,并根據(jù)物質(zhì)的輻射特性差異生成圖像。由于毫米波對(duì)雨霧、衣物等具有良好的穿透性,該技術(shù)在安全檢查、遙感、飛機(jī)盲降等領(lǐng)域得到了廣泛的應(yīng)用。為滿足應(yīng)用需求,被動(dòng)毫米波成像系統(tǒng)應(yīng)具有高亮溫靈敏度、高空間分辨率和高成像實(shí)時(shí)性的特點(diǎn)。毫米波焦平面陣列被動(dòng)成像技術(shù)具備以上特點(diǎn),是毫米波成像技術(shù)發(fā)展的重要方向之一。本文對(duì)國(guó)內(nèi)外被動(dòng)毫米波成像技術(shù)發(fā)展現(xiàn)狀進(jìn)行深入調(diào)研,采用理論分析、仿真和實(shí)驗(yàn)相結(jié)合的方法,研究了W波段焦平面陣列被動(dòng)毫米波成像的前端關(guān)鍵技術(shù),包括輻射溫度傳遞模型的建立與分析、毫米波焦平面陣列天線理論、小型化高靈敏輻射計(jì)接收通道與陣列集成、成像采樣及校準(zhǔn)等。本文首先建立了聚焦天線和輻射計(jì)通道中輻射溫度傳遞模型,利用該模型分析了輻射計(jì)輸出電壓與物體亮溫、天線效率、輻射計(jì)噪聲系數(shù)等的關(guān)系。在此基礎(chǔ)上,本文建立了雙層介質(zhì)輻射溫度傳遞模型,研究了人體隱匿的金屬和非金屬目標(biāo)與人體之間的輻射亮溫對(duì)比度隨環(huán)境溫度、介質(zhì)透射率和發(fā)射率的變化關(guān)系,并通過(guò)對(duì)比Ka和W波段輻射亮溫對(duì)比度,發(fā)現(xiàn)隱匿物與人體間的輻射溫度在W波段差異更大,更有利于成像探測(cè)。作為焦面陣被動(dòng)毫米波成像系統(tǒng)的關(guān)鍵部件,焦平面陣列天線需要在目標(biāo)平面上形成密度滿足采樣定理要求的窄均勻堆積多波束,以提高系統(tǒng)的成像空間分辨率和探測(cè)細(xì)微目標(biāo)的能力。本文采用口徑場(chǎng)積分法和等效電流法分析了拋物反射面天線的輻射特性,討論了饋源橫向偏焦時(shí)的波束偏離系數(shù)及其對(duì)波束指向均勻性的影響,以及焦平面天線中饋源陣排列及其對(duì)天線效率的影響,并研制了一款基于大口徑拋物面的新型W波段16陣元全采樣焦平面線陣天線,通過(guò)饋源陣列優(yōu)化排列,該天線實(shí)現(xiàn)了對(duì)目標(biāo)區(qū)域奈奎斯特采樣。實(shí)驗(yàn)研究表明:天線形成了16個(gè)堆積多波束,波束間增益波動(dòng)小于0.4dB,E面半功率波束寬度約為0.4±0.03°,波束指向均勻,相鄰波束間隔約為0.24°,測(cè)試結(jié)果與理論分析吻合良好,驗(yàn)證了設(shè)計(jì)方法的有效性。針對(duì)近程焦平面陣列被動(dòng)成像應(yīng)用,提出了一種準(zhǔn)光透鏡天線的精確設(shè)計(jì)和分析方法。該方法首先基于高斯波束法和幾何光學(xué)法確定透鏡天線輪廓,采用一種改進(jìn)的混合數(shù)值計(jì)算法對(duì)透鏡天線近場(chǎng)進(jìn)行準(zhǔn)確分析,并據(jù)此對(duì)透鏡天線輪廓進(jìn)行優(yōu)化。這種設(shè)計(jì)方法靈活高效,可用于設(shè)計(jì)和分析各種形式的透鏡天線,包括電大尺寸透鏡天線�；谠摲椒�,本文分別設(shè)計(jì)了W波段大口徑雙曲面透鏡天線和非球面透鏡天線,通過(guò)理論仿真與實(shí)驗(yàn)研究分析了透鏡天線的近場(chǎng)區(qū)聚焦特性。結(jié)果表明,研制的透鏡天線在距離透鏡3000mm處,聚焦焦斑小于30mm,理論計(jì)算與實(shí)測(cè)結(jié)果吻合良好。毫米波輻射計(jì)作為焦面陣被動(dòng)成像系統(tǒng)的關(guān)鍵部件,需具有亮溫靈敏度高、結(jié)構(gòu)尺寸小和通道一致性好的特點(diǎn)。本文研制了一款W波段參數(shù)可調(diào)小型化高靈敏直接檢波式輻射計(jì),解決了波導(dǎo)-共面線寬帶過(guò)渡、寬帶低噪聲放大器、寬帶高靈敏檢波等的優(yōu)化設(shè)計(jì)、小型化通道電磁兼容設(shè)計(jì)等關(guān)鍵理論和技術(shù)問(wèn)題,并通過(guò)對(duì)視頻放大、積分器、差分放大器引入調(diào)控方法,實(shí)現(xiàn)了輻射計(jì)通道參數(shù)可控,這種設(shè)計(jì)可改善多通道系統(tǒng)中的通道一致性。開(kāi)展了高度集成的雙通道輻射計(jì)模塊的實(shí)驗(yàn)研究,結(jié)果表明,輻射計(jì)的射頻等效帶寬大于20GHz,積分時(shí)間為1ms時(shí)亮溫靈敏度優(yōu)于0.5K,雙通道模塊外形規(guī)則,尺寸僅為82mm*12mm*12.1mm,適用于焦平面陣列密集排列。本文針對(duì)焦平面陣被動(dòng)成像系統(tǒng)應(yīng)用,提出了一種基于背景輻射的輻射計(jì)通道實(shí)時(shí)校準(zhǔn)方法。該方法可對(duì)焦平面陣列被動(dòng)成像系統(tǒng)接收通道一致性進(jìn)行整體校準(zhǔn),校準(zhǔn)算法簡(jiǎn)單有效,能對(duì)每幀圖像進(jìn)行校準(zhǔn)且不影響實(shí)時(shí)性,并克服了系統(tǒng)長(zhǎng)時(shí)間工作時(shí)溫度漂移對(duì)成像的影響。最后,本文研制了國(guó)內(nèi)首臺(tái)W波段24通道焦平面陣列近程被動(dòng)成像系統(tǒng),該系統(tǒng)成像視場(chǎng)范圍為13.5°(H)×36°(V),成像距離為3m時(shí)的空間分辨率優(yōu)于25mm,亮溫靈敏度優(yōu)于1K,成像速度達(dá)到4幀/秒,能有效探測(cè)人體攜帶隱匿金屬和非金屬目標(biāo)。
[Abstract]:All objects in nature produce thermal radiation in the form of electromagnetic waves. The radiation intensity of objects with different emissivity is different. Passive millimeter wave imaging technology uses the millimeter wave radiometer to receive the electromagnetic radiation of the target and generates images according to the difference of the material's radiation characteristics. It has good wear by the millimeter wave to the rain fog and the clothing. In order to meet application requirements, the passive millimeter wave imaging system should have the characteristics of high brightness temperature sensitivity, high spatial resolution and high imaging real-time characteristics. The passive imaging technology of millimeter wave focal plane array has the above features, and it is a millimeter wave imaging technology. One of the important directions of the development is to investigate the development of passive millimeter wave imaging technology at home and abroad. By means of theoretical analysis, simulation and experiment, the key technology of the front end of the passive millimeter wave imaging of W band focal plane array is studied, including the establishment and analysis of the radiation temperature transfer model and the millimeter wave focal plane array. In this paper, the relationship between the output voltage of the radiometer and the temperature of the radiometer, the efficiency of the antenna and the noise coefficient of the radiometer is analyzed. In this paper, a radiative temperature transfer model of double-layer medium is established to study the relationship between the radiant temperature contrast between the human body and the human body and the radiation temperature between the human body and the human body with the ambient temperature, the transmittance and the emissivity of the medium. By comparing the radiant temperature contrast between the Ka and the W bands, the radiation temperature between the concealed objects and the human body is found in the W band. As the key component of the focal plane array passive millimeter wave imaging system, the focal plane array antenna needs to form a narrow uniform stacked multi beam in the target plane to meet the requirements of the sampling theorem, so as to improve the spatial resolution of the system and the ability to detect the fine targets. The radiation characteristics of the parabolic reflector antenna are analyzed by the method of separation and the equivalent current method. The beam deviation coefficient and its influence on the beam pointing uniformity are discussed, as well as the arrangement of the feed array in the focal plane antenna and its influence on the efficiency of the antenna, and a new W band 16 array element based on large aperture parabolic surface is developed. A fully sampled focal plane array antenna is optimized by an array of feed arrays. The antenna realizes the Nyquist sampling of the target area. The experimental study shows that the antenna has 16 stacked multi beams, the gain fluctuation of the beam is less than 0.4dB, the half power beam width of the E surface is about 0.4 + 0.03 degrees, the beam direction is uniform and the adjacent beam spacing is about 0.24 degrees. The experimental results are in good agreement with the theoretical analysis, which verifies the effectiveness of the design method. In view of the passive imaging application of the short range focal plane array, a precise design and analysis method of the quasi optical lens antenna is proposed. The method is based on the Gauss beam method and the geometric optics method to determine the contour of the lens sky line, and an improved hybrid numerical calculation is adopted. The method is used to accurately analyze the near field of the lens antenna and optimize the outline of the lens antenna. This method is flexible and efficient, and can be used to design and analyze various forms of the lens antenna, including the large size lens antenna. Based on this method, the W band large aperture hyperbolic lens antenna and the aspheric lens antenna are designed respectively. The focusing characteristics of the lens antenna near the field are analyzed by theoretical simulation and experimental study. The results show that the focused focal spot is less than 30mm at the distance from the lens 3000mm, and the theoretical calculation is in good agreement with the measured results. The millimeter wave radiometer, as the key component of the passive imaging system of the focal plane array, needs to have high brightness temperature sensitivity. In this paper, a W band parameter adjustable and highly sensitive direct detection radiometer is developed, which solves the key theory and technical problems of broadband transition of waveguide coplanar line, broadband low noise amplifier, broadband and high sensitive detection, and the key theory and technical problems of electromagnetically compatible design of miniaturized channels. After the video amplification, the integrator and the differential amplifier introduce the control method, the channel parameters of the radiometer are controlled. This design can improve the channel consistency in the multichannel system. The experimental research on the highly integrated dual channel radiometer module is carried out. The results show that the radiometer's radio frequency equivalent bandwidth is greater than 20GHz and the integration time is 1ms. The brightness temperature sensitivity is better than 0.5K, and the dual channel module has a regular shape and only 82mm*12mm*12.1mm. It is suitable for the dense array of focal plane arrays. In this paper, a real-time calibration method of the radiometer channel based on the background radiation is proposed. This method can be used for the reception channel of the passive imaging system of the focal plane array. Conformance is calibrated as a whole. The calibration algorithm is simple and effective. It can calibrate each frame without affecting real time, and overcomes the influence of temperature drift on imaging. Finally, the first W band 24 channel focal plane array close range imaging system is developed in this paper. The imaging field range is 13.5 (H). ) by 36 degree (V), the spatial resolution of the imaging distance of 3M is better than that of 25mm, the brightness temperature sensitivity is better than that of 1K, and the imaging speed reaches 4 frames per second, and the human body can be effectively detected with the hidden metal and non metal targets.

【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：TN015

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 胡泰洋;肖澤龍;張坤;吳禮;許建中;;室內(nèi)毫米波成像的輻射溫度傳遞及對(duì)比度分析[J];光電工程;2011年01期

2 王本慶;李興國(guó);;近程毫米波合成孔徑輻射計(jì)成像算法[J];電子學(xué)報(bào);2009年06期

3 張光鋒;李興國(guó);婁國(guó)偉;;基于交流輻射計(jì)的被動(dòng)毫米波成像研究[J];紅外與毫米波學(xué)報(bào);2007年06期

4 桂良啟;張祖蔭;郭偉;;3mm波段天空亮溫的計(jì)算[J];華中科技大學(xué)學(xué)報(bào)(自然科學(xué)版);2005年12期

相關(guān)博士學(xué)位論文 前4條

1 王桂麗;毫米波精確探測(cè)系統(tǒng)的信號(hào)檢測(cè)及處理[D];南京理工大學(xué);2009年

2 肖澤龍;毫米波對(duì)人體隱匿物品輻射成像研究[D];南京理工大學(xué);2007年

3 錢嵩松;被動(dòng)毫米波陣列探測(cè)成像的關(guān)鍵技術(shù)研究[D];南京理工大學(xué);2006年

4 張光鋒;毫米波輻射特性及成像研究[D];華中科技大學(xué);2005年

，

本文編號(hào)：1782645