ABSTRACT
Contents 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 10.2 Propagation and Scattering of Millimeter-Length Waves . . . . . . . . . 308
10.2.1 Molecular Absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309 10.2.2 Attenuation in Hydrometeors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310 10.2.3 Integrated Influence of Gaseous and Hydrometeor
Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 10.2.4 Refraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 10.2.5 Underlying Terrain Irregularities . . . . . . . . . . . . . . . . . . . . . . . . . 315 10.2.6 Turbulence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315 10.2.7 Scattering and RCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
10.3 Radar Design Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318 10.3.1 Radar Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 10.3.2 Physical Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 10.3.3 Sounding Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320 10.3.4 Radar Signals and Information . . . . . . . . . . . . . . . . . . . . . . . . . . . 321 10.3.5 Spatial Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 10.3.6 Pulse Compression and Synthetic Aperture . . . . . . . . . . . . . . 323 10.3.7 Target Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325 10.3.8 Radar Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
10.3.9 Radar Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328 10.3.10 Nonclassical Types of Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
10.4 Radar Subsystems and Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330 10.4.1 Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331 10.4.2 Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332 10.4.3 Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 10.4.4 Integrated Circuits Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . 333 10.4.5 Other Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
10.5 Intelligent Transportation System Applications . . . . . . . . . . . . . . . . . . . 334 10.5.1 Role of Radar Sensors in ITS Structure . . . . . . . . . . . . . . . . . . . 334 10.5.2 Frequency Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 10.5.3 Traffic Surveillance Radar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 10.5.4 Automotive Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 10.5.5 Long-Range Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345 10.5.6 Medium-Range Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 10.5.7 Short-Range Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 10.5.8 Adaptive Cruise Control System . . . . . . . . . . . . . . . . . . . . . . . . . . 349 10.5.9 Road Departure Warning System . . . . . . . . . . . . . . . . . . . . . . . . . 350 10.5.10 Blind Spot Monitoring and Lane Change
Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 10.5.11 Obstacle Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351 10.5.12 Radar-Based Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351 10.5.13 Radar-Based Automatic Road Transportation System. . . . 352 10.5.14 Automatic Driving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
10.6 Remote Sensing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 10.6.1 Cloud Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
10.6.1.1 Introductory Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354 10.6.1.2 Features, Methods, and Advantages . . . . . . . . . . . . 354 10.6.1.3 Examples of Systems and Applications . . . . . . . . 357
10.6.2 Remote Sensing of the Terrain . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 10.7 Imaging Systems for Security and Safety Applications . . . . . . . . . . . 361
10.7.1 Miniature Radar and Radiometric Systems for CWD Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
10.7.2 Safety Navigation Applications including FOD of Airfield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
10.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
This chapter provides a radar perspective for millimeter wave propagation and scattering. It considers radar principles and the features of subsystems and components of millimeter-wave radars. Rather complicated notions of radar theory are stated in a very simple manner as a kind of overview. Then, application of millimeter-wave radar for intelligent transportation systems
(ITS) is analyzed in detail as the main section of the chapter. The role of radar sensors in ITS is shown, and frequency allocation for ITS radars is analyzed. Traffic surveillance radar, which is an element of ITS infrastructure, is described. Then automotive radars are categorized into long range, medium range, and short range, and each category is considered. On this basis different functional applications of automotive radar are briefly described. Radar-based communications for both car-to-car and the entire ITS system are considered. The necessity and possibility of data exchange using WLAN (wireless local area network) is indicated. Millimeter-wave radars are employed in a wide range of commercial, military, and scientific applications for remote sensing, safety, and measurements. That is why other important millimeter-wave radar applications are considered. Finally, the conclusion is that millimeter-wave radar is a universal instrument for numerous promising applications and a device quite suitable for network use and data exchange via wireless networks.
