1、 Microwave low noise amplifier analysis Microwave is the development of the wireless communication and development is not divided. 1901 years MaKeNi use 800 KHz medium-wave signals from Britain to the world of the north American Newfoundland first trans-atlantic radio communication test, a new era o
2、f human wireless communication. Wireless communication at the initial stage, people use long wave spread to communication. The 1920 s people discovered the shortwave communication, until the 1960 s, the rise of satellite communications, it has always been the main international long distance communi
3、cation means, and to the current emergency and military communication is still important. The waves of transmission for space is an electromagnetic wave propagation of the speed is equal to the speed of light. Radio waves can be in accordance with the frequency or wavelength classification and named
4、 we put to more than 300 MHz frequency electromagnetic wave called a microwave. Because each band spread characteristics of each different, can be used for different communication system. For example, the main wave travel along the ground, the diffraction ability strong, suitable for radio and sea c
5、ommunication. And short wave has strong the ionosphere reflection ability, it is fit to global communication. Ultrashort wave and microwave diffraction ability is bad, can be used as stadia or beyond visual range relay communication. Microwave communication is the product of the 20 th century 50 s.
6、Because of its large capacity and investment of communication cost province (accounts for about one 5 of the cable investment, high construction speed, combat ability of advantage and achieve rapid development. The 1940 s to the s produced transmission frequency band is wide, the performance is stab
7、le microwave communication, be long and large capacity wireless transmission lines to the ground of the main means, analog FM transmission capacity up to 2700 road, also can simultaneously transmit high quality color television, and then gradually entered the capacity and even in large capacity digi
8、tal microwave transmission. Since the mid 80 s, along with the frequency selective dispersion of digital microwave transmission interrupt the decline of the influence that and a series of adaptive decline against the technology and high state modulation and testing the development of technology, dig
9、ital microwave transmission produced a revolutionary change. Special should point out is the 80 s through the 90 s the set of high speed up more adaptive coding state demodulation technology and signal processing and the rapid development of the signal detection technology, to todays satellite commu
10、nication, mobile communications, digital HDTV transmission, general high-speed cable/wireless access, and high quality of the magnetic recording and many other fields of signal design and signal processing applications, which plays an important role. In developed countries in the microwave relay com
11、munication long distance communication network the proportion of as much as 50% or more. According to statistics, the United States is 66%, Japan is 50%, and the French for 54%. Since 1956, our country from east Germany introduced the first set of microwave communication equipment since, after the d
12、uplication and spontaneous development process, have made great achievements. In recent years, microwave communication systems have been huge development, thus result in microwave rf circuit performance had very great progress. And all kinds of communication system is the most critical circuit is on
13、e of the amplifier. Due to the development of semiconductor technology in the development of the amplifier is very quickly. In recent years many use microwave appeared hybrid integrated technology and single piece of microwave integrated technology of the production process of the superior performan
14、ce of amplifier. At present the microwave broadband low noise amplifier development direction of basically has two, one is to develop all kinds of power semiconductor devices, in the new type of semiconductor materials and active device based on a thorough investigation, mainly focus on the working
15、frequency of active components, gain, and power density, output power capacity of the improved； On the other hand is all kinds of high efficiency, high power, microwave/millimeter wave broadband amplifier circuit of basic theory research, this paper studies the high efficiency, high power, ultra bro
16、adband amplification of the circuit topology structure, the expanded bandwidth, gain bandwidth amplification electrical products, power bandwidth product and gain, efficiency and power output of such as improving ways and means. With the height of the development of computer technology, applied to t
17、he bo circuit design simulation software also emerge in endlessly. From the simple calculating function to the circuit simulation development now until recently electromagnetic fields mix simulation function, simulation software design ability is also been gradually strengthened. Microwave circuit s
18、imulation software launch and perfect, in the design of the amplifier to reduce artificial of calculation and improve the design precision, simplify the design process, shorten the product the development cycle has played a very perfect effect. Active simulation software to agilent development of AD
19、S most powerful software, after practice, through the ADS simulation software design out of the low noise amplifier, after circuit simulation and electromagnetic field after hybrid simulation, the actual test results and simulation of the results is good, index is satisfactory. Therefore, in the computer technique highly development today, and ADS and microwave circuit simulation software such as low noise amplifier active software research and development, can effective improve the design precision, shorten the development cycle.
