Unit 5 Radio Frequency and microwave Applications Words and expressions History ext and notes Grammar Exercises Reading material 上海海事学信息工程学院
上海海事大学信息工程学院 Unit 5 Radio Frequency and Microwave Applications Words and expressions History Text and notes Grammar Exercises Reading material
Words and expressions (7 Active adj.有源的 Alleviate vt.减轻;缓和 ■ Antenna n.天线 ■ Carrier n.载波 a Cautery n.烙(术):烙器;烧灼剂 ■ Channel n.频道;信道 Coax n.同轴电缆 Collision n.碰撞;抵触 ■ Coordinate n.坐标(用复数) ■ Diffraction n.衍射 ■ Entity n.实体;存在;本质 ■ Hemorrhage n.出血 Incident adi.入射的,投在或射在一表面的 Interference n.干扰 ■| onosphere n.电离层 ■ Magnetism n.磁性;磁力 上海海学信息工程学院
上海海事大学信息工程学院 Words and expressions ◼ Active adj. 有源的 ◼ Alleviate vt. 减轻；缓和 ◼ Antenna n. 天线 ◼ Carrier n. 载波 ◼ Cautery n. 烙(术)；烙器；烧灼剂 ◼ Channel n. 频道；信道 ◼ Coax n. 同轴电缆 ◼ Collision n. 碰撞；抵触 ◼ Coordinate n. 坐标(用复数) ◼ Diffraction n. 衍射 ◼ Entity n. 实体；存在；本质 ◼ Hemorrhage n. 出血 ◼ Incident adj. 入射的，投在或射在一表面的 ◼ Interference n. 干扰 ◼ Ionosphere n. 电离层 ◼ Magnetism n. 磁性；磁力
Words and expressions 7 Meteorology n.气象学,气象状态□ Metropolitan a.大都市的 Optical adj.眼镜的;视力的;光学的 ■ Orientation n.定位;定向 Ozone n.新鲜的空气,[化]臭氧 Propagation n.(声波,电磁辐射等)传播 ■■■ Sterilization n.杀菌,绝育 Surveillance n.监视,监督 Via prep经由;取道 Cut-off frequency 截止频率 a Transverse MagnetIc (TM) 横磁(性)的 ■ Lay the foundation of 给.打下基础,为..奠定基础 Line-of-sight 视线,瞄准线 ■ Modulating signal 调制信号 上海海学信息工程学院
上海海事大学信息工程学院 Words and expressions ◼ Meteorology n. 气象学，气象状态 ◼ Metropolitan a. 大都市的 ◼ Optical adj. 眼镜的；视力的；光学的 ◼ Orientation n. 定位；定向 ◼ Ozone n. 新鲜的空气，[化]臭氧 ◼ Propagation n. (声波，电磁辐射等)传播 ◼ Sterilization n. 杀菌，绝育 ◼ Surveillance n. 监视，监督 ◼ Via prep.经由；取道 ◼ Cut-off frequency 截止频率 ◼ Transverse Magnetic (TM) 横磁(性)的 ◼ Lay the foundation of 给…打下基础，为…奠定基础 ◼ Line-of-sight 视线，瞄准线 ◼ Modulating signal 调制信号
History(from google James clark Maxwell: (1831-1879 In the 1860s and 1870s, James Clerk Maxwell developed the theory of electric and magnetic forces, summarized in his famous four equations. these equations encapsulated all that had been discovered about electricity and magnetism in the experiments done over the previous few hundred years by Faraday, Volta, and many others. They showed that electricity and magnetism were two aspects of the same force. The equations also predicted that there should be a form of radiation which came to be known as electromagnetic radiation Maxwell realized that light was a form of electromagnetic radiation Around 1862 he wrote We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena The equations predicted that electromagnetic radiation could exist with any wavelength. The various colors of light have wavelengths less than a thousandth of a millimeter. Much longer wavelengths are possible 上海海学信息工程学院
上海海事大学信息工程学院 History (from google) ◼ James Clark Maxwell: (1831-1879) ◼ In the 1860s and 1870s, James Clerk Maxwell developed the theory of electric and magnetic forces, summarized in his famous four equations. These equations encapsulated all that had been discovered about electricity and magnetism in the experiments done over the previous few hundred years by Faraday, Volta, and many others. They showed that electricity and magnetism were two aspects of the same force. The equations also predicted that there should be a form of radiation, which came to be known as electromagnetic radiation. Maxwell realized that light was a form of electromagnetic radiation. Around 1862 he wrote, "We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena." ◼ The equations predicted that electromagnetic radiation could exist with any wavelength. The various colors of light have wavelengths less than a thousandth of a millimeter. Much longer wavelengths are possible
History(from google) Oliver Heaviside(1850-1925 I Heaviside and Kennelly, in 1902, predicted that there should be an ionised layer(电离层) in the upper atmosphere that would reflect radio waves. They pointed out that it would be useful for long distance communication, allowing radio signals to travel to distant parts of the earth by bouncing off the underside of this layer. The existence of the layer, now known as the heaviside layer or the ionosphere, was demonstrated in the 1920s If radio waves bounce off the inside of the ionosphere, then they must also bounce off the outside so any radio waves from outside the earth would not get through to the ground -- they would bounce back into space a Thus the predictions by Heaviside, combined with Planck's radiation theory, probably discouraged further attempts to detect radio waves from the Sun and other celestial objects. For whatever reason, there seem to have been no attempts for 30 years, until Jansky's unexpected discovery in 1932 Later it was learned that the reflection from the ionosphere is very dependent on the frequency (or wavelength) it reflects most of the radiation of frequency less than about 20 MHz. but the ionosphere is not a barrier to frequencies above about 50 MHZ Radio astronomy had to wait for the development of high frequency radio receivers 上海海学信息工程学院
上海海事大学信息工程学院 History (from google) ◼ Oliver Heaviside (1850-1925) ◼ Heaviside and Kennelly, in 1902, predicted that there should be an ionised layer (电离层） in the upper atmosphere that would reflect radio waves. They pointed out that it would be useful for long distance communication, allowing radio signals to travel to distant parts of the earth by bouncing off the underside of this layer. The existence of the layer, now known as the Heaviside layer or the ionosphere, was demonstrated in the 1920s. ◼ If radio waves bounce off the inside of the ionosphere, then they must also bounce off the outside. So any radio waves from outside the earth would not get through to the ground -- they would bounce back into space. ◼ Thus the predictions by Heaviside, combined with Planck's radiation theory, probably discouraged further attempts to detect radio waves from the Sun and other celestial objects. For whatever reason, there seem to have been no attempts for 30 years, until Jansky's unexpected discovery in 1932. ◼ Later it was learned that the reflection from the ionosphere is very dependent on the frequency (or wavelength). It reflects most of the radiation of frequency less than about 20 MHz. But the ionosphere is not a barrier to frequencies above about 50 MHz. Radio astronomy had to wait for the development of high frequency radio receivers
History(from google) Guglielmo Marconi (1874-1937) Marconi improved radio transmission and receiver designs and developed the first practical systems for long distance communication by radio. In 1901 he was the first to send and receive signals across an ocean from newfoundland to Cornwall. As a result of his pioneering efforts, commercial radiotelephone service became available in later years In the 1930s the bell telephone company was working on improving heir transatlantic telephone service when they assigned Karl Jansky to investigate sources of radio static, leading to his discovery of radio waves from the milky way 上海海学信息工程学院
上海海事大学信息工程学院 History (from google) ◼ Guglielmo Marconi (1874-1937) ◼ Marconi improved radio transmission and receiver designs and developed the first practical systems for long distance communication by radio. In 1901 he was the first to send and receive signals across an ocean, from Newfoundland to Cornwall. As a result of his pioneering efforts, commercial radiotelephone service became available in later years. In the 1930s the Bell Telephone company was working on improving their transatlantic telephone service when they assigned Karl Jansky to investigate sources of radio static, leading to his discovery of radio waves from the milky way
History(from google) Heinrich Hertz(1857-1894 In 1888, Heinrich Hertz built an apparatus that could transmit and receive electromagnetic waves of about 5 meters in I length. he used a coil to generate a high voltage spark between two electrodes which served as a transmitter The detector was a loop of wire with a small gap. A spark at the transmitter produces electromagnetic waves that travel to the detector, producing a spark in the gap. He showed that the waves were polarized, and that they could interfere with each other, just as predicted by theory 上海海学信息工程学院
上海海事大学信息工程学院 History (from google) ◼ Heinrich Hertz (1857-1894) ◼ In 1888, Heinrich Hertz built an apparatus that could transmit and receive electromagnetic waves of about 5 meters in length. He used a coil to generate a high voltage spark between two electrodes which served as a transmitter. The detector was a loop of wire with a small gap. A spark at the transmitter produces electromagnetic waves that travel to the detector, producing a spark in the gap. He showed that the waves were polarized, and that they could interfere with each other, just as predicted by theory
History(from google ■ Lord rayleigh John william Strutt, 3rd Baron Rayleigh OM (12 November 1842-30 June 1919)was an English physicist who, with William Ramsay discovered the element argon, an achievement for which he earned the nobel prize for hysics in 1904. He also discovered the phenomenon now called Rayleigh scattering, explaining why the sky is blue, and predicted the existence of the surface waves now known as Rayleigh waves. In 1910 Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced active nitrogen",an allotrope considered to be monatomic. The whirling cloud of brilliant yellow light"produced by his apparatus reacted with quicksilver to produce explosive mercury nitride 上海海学信息工程学院
上海海事大学信息工程学院 History (from google) ◼ Lord Rayleigh ◼ John William Strutt, 3rd Baron Rayleigh OM (12 November 1842 – 30 June 1919) was an English physicist who, with William Ramsay, discovered the element argon, an achievement for which he earned the Nobel Prize for Physics in 1904. He also discovered the phenomenon now called Rayleigh scattering, explaining why the sky is blue, and predicted the existence of the surface waves now known as Rayleigh waves. In 1910 Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced "active nitrogen", an allotrope considered to be monatomic. The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with quicksilver to produce explosive mercury nitride
Questions about this article a Question 1: What is this article from? Question 2: Can you give some examples about the application about RF/Microwave? 上海海学信息工程学院
上海海事大学信息工程学院 Questions about this article ◼ Question 1: what is this article from? ◼ Question 2: Can you give some examples about the application about RF/Microwave?
Example about applications of RF/Microwave ::::: went 面生 基于电子标签的集装箱管理系统结构图 上海海学信息工程学院
上海海事大学信息工程学院 Example about applications of RF/Microwave