TAILIEUCHUNG - Lò vi sóng RF và hệ thống không dây P7

Radar and Sensor Systems Radar stands for radio detection and ranging. It operates by radiating electromagnetic waves and detecting the echo returned from the targets. The nature of an echo signal provides information about the target—range, direction, and velocity. Although radar cannot reorganize the color of the object and resolve the detailed features of the target like the human eye, it can see through darkness, fog and rain, and over a much longer range. | RF and Microwave Wireless Systems. Kai Chang Copyright 2000 John Wiley Sons Inc. ISBNs 0-471-35199-7 Hardback 0-471-22432-4 Electronic CHAPTER SEVEN Radar and Sensor Systems INTRODUCTION AND CLASSIFICATIONS Radar stands for radio detection and ranging. It operates by radiating electromagnetic waves and detecting the echo returned from the targets. The nature of an echo signal provides information about the target range direction and velocity. Although radar cannot reorganize the color of the object and resolve the detailed features of the target like the human eye it can see through darkness fog and rain and over a much longer range. It can also measure the range direction and velocity of the target. A basic radar consists of a transmitter a receiver and a transmitting and receiving antenna. A very small portion of the transmitted energy is intercepted and reflected by the target. A part of the reflection is reradiated back to the radar this is called back-reradiation as shown in Fig. . The back-reradiation is received by the radar amplified and processed. The range to the target is found from the time it takes for the transmitted signal to travel to the target and back. The direction or angular position of the target is determined by the arrival angle of the returned signal. A directive antenna with a narrow beamwidth is generally used to find the direction. The relative motion of the target can be determined from the doppler shift in the carrier frequency of the returned signal. Although the basic concept is fairly simple the actual implementation of radar could be complicated in order to obtain the information in a complex environment. A sophisticated radar is required to search detect and track multiple targets in a hostile environment to identify the target from land and sea clutter and to discern the target from its size and shape. To search and track targets would require mechanical or electronic scanning of the antenna beam. For mechanical scanning a

• Kĩ thuật Viễn thông
• Lò vi sóng RF
• hệ thống không dây
• truyền thông không gian
• hệ thống sóng RF
• mạch lò vi sóng
• Bộ lọc Microstrip
• ứng dụng lò vi sóng
• ứng dụng Microstrip
• sóng viba
• Mạch RF
• lò vi sóng
• mạch lạc lò vi sóng
• tín hiệu điện