【摘要】：當前在全球范圍內(nèi),雷達系統(tǒng)已經(jīng)廣泛地使用于陸、海、空和地球外層空間。雷達技術(shù)和電子對抗技術(shù)發(fā)展日新月異,雷達系統(tǒng)及其工作環(huán)境越來越復(fù)雜,要求雷達具有較強的抗干擾能力,因此,作為雷達的關(guān)鍵部分,接收機的設(shè)計要求被提得越來越高。設(shè)計雷達接收機,不僅需要考慮被探測目標的信號,還需要考慮探測提取過程中出現(xiàn)的各種噪聲和干擾。接收機前端的性能指標對雷達系統(tǒng)有顯著的影響,伴隨微波技術(shù)的發(fā)展,元器件的指標和制造工藝水平有極大飛躍,為提高接收機的集成度創(chuàng)造了條件,尤其是為減小接收機前端的體積提供了支持。將接收機前端壓縮到較小體積,順應(yīng)雷達系統(tǒng)的小型化趨勢。本文介紹了幾種雷達接收機的工作模式,最終采用超外差方式設(shè)計接收機,超外差式接收機主要包含了接收機前端、頻率源和中頻放大電路等部分。文章主要對超外差接收機的原理進行分析,分別闡述了限幅器、低噪聲放大器、濾波器、混頻器、頻率源在接收機中的原理和作用,提出了設(shè)計方案并加以仿真及實現(xiàn)。在設(shè)計中采用的中頻部分電路較為簡單,不做詳細描述。在接收機的前端中,限幅器在最靠前的位置,保護低噪聲放大器在大信號到來時不被燒毀;低噪聲放大器的作用至關(guān)重要,決定了噪聲系數(shù)等關(guān)鍵指標;為降低噪聲系數(shù),將MEMS濾波器設(shè)置在低噪聲放大器之后,起到抑制帶外雜波的作用;第一級混頻器將15.5±0.5GHz的射頻信號變?yōu)?.5±0.5GHz,第二級混頻器將2.5±0.5GHz的射頻信號變?yōu)?.15GHz,得到中頻輸出信號;頻率源要求提供兩路射頻輸出,分別作為一本振和二本振,一本振的頻率為13GHz,二本振的頻率為2.35±0.5GHz。在各章節(jié)之后列出了關(guān)鍵器件的測試結(jié)果,與預(yù)期指標進行對比和說明。本文實現(xiàn)的超外差雷達接收機,達到了接收機任務(wù)的技術(shù)指標,不僅具有高靈敏度、低噪聲系數(shù)、信號選擇性好及工作性能穩(wěn)定等特點,還突破了以往的模塊化設(shè)計,實現(xiàn)了符合工程需要的高集成度、小體積的接收機,符合了雷達系統(tǒng)的小型化趨勢。
[Abstract]:At present, radar systems are widely used in land, sea, air and outer space around the world. With the rapid development of radar technology and electronic countermeasure technology, radar system and its working environment are becoming more and more complex, which requires radar to have strong anti-jamming capability. Therefore, as a key part of radar, The design requirements of the receiver are getting higher and higher. To design a radar receiver, not only the signal of the target to be detected, but also all kinds of noise and interference in the detection and extraction process should be considered. The performance index of the front end of the receiver has a remarkable influence on the radar system. With the development of microwave technology, the index of components and the manufacturing technology have made a great leap forward, which has created conditions for improving the integration of the receiver. In particular, support is provided for reducing the volume of the front end of the receiver. The receiver front end is compressed to a smaller volume, following the trend of radar system miniaturization. In this paper, several working modes of radar receiver are introduced. Finally, the superheterodyne receiver is designed. The superheterodyne receiver mainly includes the front end of the receiver, the frequency source and the if amplifier circuit. In this paper, the principle of superheterodyne receiver is analyzed, and the principle and function of limiter, low noise amplifier, filter, mixer and frequency source in the receiver are expounded, and the design scheme is put forward and simulated and realized. The if circuit used in the design is simple and not described in detail. In the front end of the receiver, the limiter is in the front position to protect the low noise amplifier from being destroyed when the large signal arrives, and the function of the low noise amplifier is very important, which determines the key index such as noise coefficient, and so on. In order to reduce the noise coefficient, the MEMS filter is set behind the low noise amplifier to suppress the out-of-band clutter. In the first stage, the RF signal of 15.5 鹵0.5GHz is changed into 2.5 鹵0.5 GHz, the second stage mixer changes the 2.5 鹵0.5GHz RF signal to 0.15 GHz, and the intermediate frequency output signal is obtained. The frequency source is required to provide two RF outputs, one oscillator and two oscillator, the frequency of one oscillator is 13 GHz, and the frequency of local oscillator is 2.35 鹵0.5 GHz. After each chapter, the test results of the key devices are listed, and compared with the expected indicators. The superheterodyne radar receiver realized in this paper not only has the characteristics of high sensitivity, low noise coefficient, good signal selectivity and stable working performance, but also breaks through the previous modular design. The high integration and small volume receiver are realized, which accord with the trend of radar system miniaturization.
【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】：TN965.5
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本文編號：2303135