【文章內(nèi)容簡(jiǎn)介】 he operators can give good support. The future, the microwave transmission system will be upgraded to allIP platform, can fully support the future development of the operators. (Ix) satellite munications technology The use of satellite with terrestrial munications in some not very densely populated areas. Scattered in these areas, but not intensive users of a wider scope, you can use the satellite as a user connected to the fixed wireline work access facilities. Terrestrial munications work constitutes a broadband multimedia munications work, using the satellite into a broadband satellite access system is relatively good and realistic program, and reliable. Satellite munications, after all, the construction of the satellite as a munications platform, the ground station, the munication channel rental costs need to spend a lot of money, and munication resources for the satellite munications pany, by its bandwidth limit, the transmission of large amounts of data need to pay a very high price. Therefore, as the daily production, the life use is extremely uneconomical。 and satellite munications are more suitable as emergency munications, bat munications, overseas munications. (1)Introduction Four after the 17th century discovered how to generate electricity with a metal wire transfer of power. Today, for the power grid, power lines around the world every corner. Work and life, more and more electrical appliances brought us great convenience at the same time, knew the power cord of a variety of disarray troubled by the data line is also increasing. However, all these years of technological development, the growing popularity of wireless data transmission technology, scientists have a great breakthrough in wireless power transmission (Wireless Power Transmission WPT), a sense, the wireless power transmission is no longer a fantasy get rid of the chaos of the power cord has bee possible in the future life. (2) the history of the development of wireless power transmission In the late 19th century known as usher in the power era of genius. Mingnigula Tesla (Nikola Tesla ,18561943) made outstanding contributions to electrical and radio technology. 1881 he discovered the rotating magic field principle, and for the manufacture of induction motor。 the 1888 invention of multiphase AC transmission and distribution system。 made from 18891890 Hz oscillator。 1891 invention of highfrequency transformer (Tesla Coil) are still widely used in radio, TV and other electronic equipment. He has mitted to research wireless transmission of signals and the possibility of energy in 1899 without wires using highfrequency current of the motor, but due to low efficiency and the security concerns of wireless power transmission technology breakthrough [ 1]. 19011905 years, built in the vicinity of New York39。s Long Island Wardenclyffe tower, is a plex electromagic oscillator, conceived it to be able to power transmission to any corner of the world, Tesla use of this tower to achieve the resonance of the Earth and the ionosphere. In May 2021, the French National Centre for Scientific Research 皮格努萊特 microwave wireless transmission of electrical energy to light up the 40m outside a 200W light bulb. Subsequently, in 2021 built on the island of 10kW experimental microwave transmission equipment, has begun to frequency close to 1km Grande Basang Village for pointtopoint wireless power. In 2021, the City University of Hong Kong Department of Electronic Engineering, Professor Xu Shuyuan successfully developed a wireless battery charging platform , but its use still want products and charger contacts. In October 2021, Japan exhibited a wireless power transmission system. The output power of this system is 7V, 400mA, send and receive coil spacing is 4mm, the transmission efficiency of 50% for the phone to fast charge. In June 2021, the Massachusetts Institute of Technology assistant professor of physics the Marin 索爾賈?？? research team within a short distance wireless power transmission. They give a 60 cm diameter coil is energized, and 6 feet (about meters) outside the connection in another coil 60 watt light bulb lit up. The principle of this Marin called WiTricity technology magically coupled resonance. In September 2021, the papers published by the North American Electric Workshop, they have been successful in Nevada Lightning Laboratory 800W power with a wireless way of transmission to 5m far distance. In October 2021, Nara, Japan, plugin hybrid bus wireless charging experiment. Powered coil buried in the concrete charge, the car onto the charge, the vehicle coil at the powered coil will be able to start charging. 3 the basic principles of wireless power transmission of electromagic induction shortrange transmission The phenomenon of electromagic induction is the most significant discoveries in electromagism, one of which shows the linkages and transformation between the electric and magic phenomena. Electromagic induction is the basic principles of electromagism, the transformer is to use the basic principle of electromagic induction to work. Magic coupling to transfer energy between the basic principles of electromagic induction distance power transmission shown in Figure 1, the transmitting coil L1 and the receiving coil L2. The coil L1 through the alternating current, the current in the surrounding medium, the formation of an alternating magic field, the EMF generated in the coil L2 can supply to the mobile device or to charge the battery. of electromagic coupling resonance mediumrange transmission The mediumrange wireless power transmission is the radio frequency electromagic wave or nonradiative resonant magic coupling form of power transmission. It is based on electromagic resonance coupling principle, the use of nonradiative magic fie