FMCW雷达系统及其前端数据采集模块设计

(FMCW)调频连续波雷达在汽车防撞系统中得到了广泛的应用。文中对近年来国内外汽车防撞系统的发展做了阐述和比较,以FMCW毫米波雷达作为系统前端,对防撞系统的原理、结构、信号的前置放大和模数转换等关键数据采集模块进行了介绍与设计。     

Low-Noise Millimeter-Wave Receivers

Over the past several years, significant improvements have been made in solid-state devices (that is, avalanche diodes, Gunn diodes, varactors, mixer diodes, etc.) that have enhanced the overall capability and low-noise performance of millimeter-wave receivers. With these improved devices, it is now possible to configure completely solid-state low-noise millimeter-wave receivers. As is similar in the microwave region, low-noise parametric amplifiers, broad-band low-conversion-loss mixers, and solid-state local oscillators are now available. Furthermore, cryogenically cooled parametric amplifiers and mixers are also being developed that will result in achieving the ultimate in system sensitivity. With the flexibility offered by these completely solid-state millimeter-wave components, it is now possible to design the optimum system configuration for the intended application whether it be an advanced communication system, a sophisticated EW application, a RADAR system, a radiometric system, or satisfying any of the numerous receiver requirements that are being evolved. This paper explores the trends that are being developed in the millimeter-wave region and their application to system design. The performance criterion of various receiver systems and their sensitivity requirements are presented. A review of the system operating noise temperature concept and the method by which it can be determined and its applicability to low-noise components is demonstrated. A review of the state-of-the-art of low-noise systems and experimental data obtained in the millimeter-wave region is also presented.     

Millimeter-wave research activities in Japan

Millimeter-wave research activities in Japan are reviewed from various points of view. It is shown that a quarter of the papers presented at microwave sessions in the two major annual conferences of the Institute of Electronics. Information and Communications Engineers (IEICE), Japan, are millimeter-wave research papers. Monolithic microwave integrated circuit (MMIC) devices such as high-power amplifiers (HPAs), low-noise amplifiers (LNAs), and mixers developed by several companies are compared in terms of state-of-the-art performances. Unique cost-reduction techniques are also discussed. Two types of car collision-avoidance radar systems have been constructed using nonradiative dielectric waveguide (NRD-guide) technology peculiar to Japan. Topics presented at Microwave Photonics '96, Japan, are reviewed, with emphasis on the Japanese contributions to this field     

毫米波雷达自适应门限点云成像方法研究

毫米波雷达作为一种重要的车载传感器,在自动驾驶领域得到了广泛地应用。近年来随着汽车智能化程度的提高,高质量雷达点云的生成受到了人们的极大关注。传统毫米波雷达点云成像由于存在杂波点太多、有效点云稀疏等缺点而限制了其在自动驾驶领域的发展。因此,如何提高毫米波雷达点云密度和质量成为了业界研究的重点问题。近年来,随着多输入多输出（MIMO）技术以及控制多片级联同步技术的成熟,使得毫米波雷达天线的角度分辨率得到了极大提升,推动了毫米波雷达在点云成像上的发展。在此基础上,本文设计了一套完整的毫米波雷达系统级点云成像算法,并使用TI公司的AWR2243级联雷达开发套件对实际场景进行数据采集,生成了较为致密可信的毫米波雷达三维点云图像,基本实现了对车载平台侧面场景的有效还原。      

毫米波相控阵板级集成天线技术研究

随着毫米波雷达及通信系统的快速发展,有源相控阵天线日益成为当前研究的热门天线形式。然而,毫米波有源相控阵存在空间紧凑、结构复杂、装配繁琐等问题。本文介绍了一种可应用于毫米波相控阵的板级集成天线,并对其天线阵列、垂直过渡等关键结构的设计进行了讨论。该阵面将天线阵列、收发组件和馈电网络全部集成在一块基板上,具有结构简单易于量产的特点。文末给出了对所设计的有源阵面的暗室测试结果,结果表明该天线在毫米波雷达和通信系统中具有巨大的应用潜力。     

Characteristics and applications of fast-wave gyrodevices

Gyrodevice oscillators and amplifiers (or gyro-oscillators and gyro-amplifiers) are being utilized in a variety of applications where high power levels are required at millimeter-wave frequencies. Gyro-oscillators, developed primarily for magnetic fusion research applications, have achieved power levels near 1 MW for pulse durations in excess of 1 s at frequencies above 100 GHz. Continued work on these devices should enable them to achieve continuous-wave operation at multimegawatt power levels at frequencies in the 100-GHz to 200-GHz range, thereby meeting the requirements of planned magnetic fusion experiments. The development of gyro-oscillators for fusion experiments has led to the utilization of the devices in several industrial applications, such as ceramic sintering and metal joining. Activities in this area involve adapting the oscillators to the industrial environment where reliability, efficiency, and ease of operation are paramount. Gyro-amplifiers are being developed for applications requiring phase coherence and instantaneous bandwidth, such as in linear accelerators and millimeter-wave radar. Impressive results from X-band to W-band already suggest the promise of these devices. Potential new applications and novel gyrodevice design approaches continue to attract the attention of researchers around the world     

固态微波毫米波器件技术进展

固态微波毫米波半导体材料与器件、固态微波毫米波电路与模块、毫米波与太赫兹技术以及新型固态微波毫米波器件在近年来有很大的发展,在相控阵雷达、电子战、军民用通信领域有广泛的应用前景。当前这些器件应用较为集中于各类T/R组件。文章按固态微波毫米波半导体材料与器件、固态微波毫米波电路与模块、毫米波与太赫兹技术以及新型固态微波毫米波器件的顺序,概要介绍了固态微波毫米波技术的新进展。     

Microwave and Millimeter-Wave Communications in Japan

This paper reviews the status of research and development in both microwave radio-relay systems and millimeter-wave transmission systems as well as the technical features in these fields, mainly developed under the auspices of Nippon Telegraph and Telephone Public Corporation (NTT). Recent activities have been the development of new solid-state devices and high-capacity systems. The application of solid-state techniques is being extended to systems of both analog and digital transmission, such as the 2700 multichannel telephone transmission system in frequency division multiplexing (FDM)-FM radio-relay system, an experimental 20-GHz PCM radio-relay system capable of 400 Mbits/s pulse transmission, and a guided millimeter-wave system of 800-Mbit/s transmission at 40-80 GHz. The microwave integrated circuit (MIC) is also becoming very important in utilizing these high-frequency regions, which should be a valuable resource in the future when a vast information transmission capability will be required.     

An overview of very high capacity transmission technology for NTT networks

This paper describes very high capacity optical transmission system technology, which is useful for long-haul trunk lines, and has led to the feasibility of NTT's first gigabit-per-second range transmission system. It also describes various devices and circuits, such as high performance lasers, photodetectors, very wide-band amplifiers, and high speed logic circuits required for the development of such systems. It then discusses future research areas and trends in advanced lightwave communication systems.     

基于PC104的汽车防碰预警系统的设计

毫米波雷达硬件体积小、探测精度高和全天候工作等特点,不仅具有很高的隐蔽性和很好的抗干扰性能,同时兼有微波和红外探测的优点,近年来受到了广泛重视。文中提出一种基于线性频率调制连续波雷达的汽车防碰预警系统,给出了系统的基本结构,并对前端数据采集、数据缓存和PCI04数据引入3部分进行分析设计,最后通过系统联调实现了汽车防碰预警等功能。     

50-GHz IC Components Using Alumina Substrates

This paper discusses the feasibility of employing alumina substrates instead of fused quartz or sapphire substrates in millimeter-wave integrated circuits (IC's), an attractive prospect since alumina boasts considerable advantages over either of the other materials. Millimeter-wave 50-GHz components were developed on alumina substrates. These included passive components, a mixer, an ASK modulator, and an oscillator. Empirical results for both oscillator stabilization using a dielectric resonator and a new application of a GaAs FET in a millimeter-wave oscillator-doubler are presented. Examples of integrated systems using millimeter-wave IC'S are also presented. These systems include a compact Doppler radar front-end for an automobile ground-speed sensor, and a transmitter/receiver for digital radio equipment. All of them are fabricated on alumina substrates.     

Millimeter-wave radars for remotely sensing clouds andprecipitation

Millimeter-wave radars have been used since the early 1950s to study clouds and precipitation, but until recently these early instruments were limited to simple backscatter power measurements and were plagued by hardware problems. However, development of solid-state millimeter-wave componentry and high-power klystron amplifiers has spurred the evolution of reliable, coherent radars operating up to 95 GHz. In addition, advances in digital signal processing technology have resulted in single-card processors that can simultaneously execute algorithms to compute reflectivity, Doppler, and polarimetric quantities in real time. A review of the current state of the art in millimeter-wave cloud radars is presented, including a discussion of transmitters, antennas, and receiver components. Two radar systems built by the University of Massachusetts are described, including a mobile, dual-frequency (33- and 95-GHz) polarimetric radar, and an airborne 95-GHz polarimetric radar that was recently flown in a cooperative experiment with the University of Wyoming. Spaceborne applications are also discussed, especially the use of satellite-based 95-GHz radars for measuring the vertical distribution of clouds     

Sensors and systems to enhance aviation safety against weatherhazards

The authors describe the physics of adverse weather, the basics of Doppler engineering, and a host of advanced sensing systems-some with the ability to autonomously identify and track storm conditions-for all stages of airplane travel. Three major new Doppler radar systems are discussed: the next generation weather radar, the terminal Doppler weather radar, and the airport surveillance radar with a dedicated weather channel. Other relatively simple new instruments for aviation weather support include the low level wind shear alert system, the Doppler wind profilers, the automated weather observation system, and the automated surface observation system. These systems are designed to perform higher level functions such as detection, characterization, and hazard potential estimation of aviation-significant weather phenomena, as well as their communication and display automatically     

Development of Ka-band 100-W peak power MMPM

Various types of millimeter-wave radio systems are being developed for strong broadband service demands such as fixed wireless access, local multipoint distribution service, as well as satellite communications. In each system, the higher data rate transmission requires more powerful amplification devices. This paper describes the development of a Ka-band 100-W peak power millimeter-wave power module, traveling wave tube-based millimeter-wave amplification module, used for millimeter-wave fixed wireless access base stations and Ka-band satellite Internet terminals.     

Reliability life-testing and failure-analysis of GaAs monolithicKu-band driver amplifiers

`Gallium-arsenide monolithic microwave integrated-circuit (MMIC) Ku-band driver amplifiers were life tested under accelerated high temperature, DC and RF conditions until failure. These MMIC are used in various applications such as radar and satellite communication systems. The failure mechanisms controlling their reliability must be understood in order to improve the lifetime for these and other applications. This paper discusses the experimental procedures, statistical evaluation of the data and failure analysis of the devices. To the authors' knowledge, this is the first report of RF life testing of dual-gate driver amplifiers. The majority of the devices failed catastrophically due to high drain current, while others failed parametrically due to low output power. Failure analysis indicates that degradation of the Si₃N₄ dielectric layer to be the main failure mechanism in these MMIC. Statistical analysis revealed an activation energy of 0.87 eV and a median lifetime of 5.8·10⁴ hours at 140°C channel temperature, which is consistent with surface-phenomena failure mechanisms     

利用卷积神经网络进行毫米波图像违禁物体定位

随着毫米波器件的成熟,毫米波成像雷达已经应用于人体安检.但毫米波图像中违禁物体的定位仍然是一个艰巨的任务,这极大地限制了毫米波成像雷达的应用.文章将卷积神经网络(Convolutional Neural Network,CNN)应用于毫米波图像,自动定位毫米波图像中的违禁物体,如枪、刀等.利用滑动窗口在输入图像上滑动,并通过CNN得到各个子图块存在违禁物体的概率.图像块是相互交叠的,将各子图块的概率值累积起来,得到概率累积图.概率累计图反映了违禁物体的位置.由于CNN和概率累积图的应用,在实验中,该方法获得了很高的定位准确率,验证了该方法的有效性.     

毫米波合成孔径雷达的发展及其应用

分析了毫米波SAR高分辨成像的基本原理,阐述了毫米波SAR的优点,并结合目前国际上典型的毫米波SAR系统,综述了毫米波SAR技术与系统的发展状况,讨论了毫米波SAR的应用前景、存在的问题以及未来的发展趋势.     

Advanced CAD tool for noise modeling of RF/microwave field effect transistors with large gate widths

In the millimeter-wave frequency range, electromagnetic (EM) effects can significantly influence a device behavior. As the core of modern communication systems, active devices such as field effect transistors (FETs) require up-to-date models to accurately integrate such effects, especially in terms of noise performance since most of communication systems operate in noisy environments. Furthermore, to keep low-noise amplification over a wide frequency band, the transistor noise resistance R_n must be substantially reduced to make the system insensitive to impedance matching. Since this can be realized through large gate-width devices, a novel large gate-width FET noise model is proposed which efficiently integrates EM wave propagation effects, one of the most important EM effects in mm-wave frequencies.     

An algorithm for detecting roads and obstacles in radar images

This paper describes an algorithm for detecting roads and obstacles in radar data taken from a millimeter-wave imaging platform mounted on a stationary automobile. Such an algorithm is useful in a system that provides all-weather driving assistance. Road boundaries are detected first. The prior shape of the road boundaries is modeled as a deformable template that describes the road edges in terms of its curvature, orientation, and offset. This template is matched to the underlying gradient field of the radar data using a new criterion. The Metropolis algorithm is used to deform the template so that it “best” matches the underlying gradient field. Obstacles are detected next. The radar returns from image pixels that are identified as being part of the road are processed again, and their power levels are compared to a threshold. Pixels belonging to the road that return a significant (greater than a fixed threshold) amount of incident radar power are identified as potential obstacles. The performance of the algorithm on a large all-weather data set is documented. The road edges and obstacles detected are consistently close to ground truth over the entire data set. A new method for computing the gradient field of radar data is also reported, along with an exposition of the millimeter-wave radar imaging process from a signal-processing perspective