One, day line: ( antenna ) is the high frequency current or wave form of energy is converted intoelectromagnetic wave and to the specified direction transmitted from a certain direction or electromagneticwave reduction for high frequency current to a device.

In two, the antenna classification: 1 ) according to the purpose of the classification: can be divided intocommunications antenna, antenna, radar antenna; 2) according to the working frequency band can be divided into categories: shortwave antenna, UHF antenna, microwave antennas; 3) according to thedirection of classification: can be divided into omnidirectional antenna, a directional antenna; 4) according to the shape classification; can be divided into linear antenna, planar antenna.

In three, an omnidirectional antenna, namely in the horizontal direction map showed 360 °uniform radiation,it is usually said no direction, in the vertical direction diagram on the performance of a certain width of thebeam, the beam width is generally small, gain is big.

In four, a directional antenna, in the horizontal diagram shows a certain range of radiation, it is usually saidto have direction, in a direction perpendicular to a width of the beam, the omnidirectional antenna, beam width is small, gain is big.

In five, the gain of the gain refers to: the input power equal conditions, the actual antenna radiating elements and the ideal premises in the same point in space generated by the ratio of signal power density.It is a quantitative description of an antenna input power concentrated radiation level. Gain obviously and the antenna has the close relationship, direction of main lobe side lobe narrower, smaller, gain more and more high. This can be understood gain physical meaning - - - - - - is in a certain distance on a pointproduces a certain size signal, if the desired direction of point source as a transmitting antenna, need 100Winput power, and gain of G = 13 dB = 20 for a directional antenna as a transmitting antenna when the input power, only 100 / 20 = 5W. In other words, a gain of the antennas, the maximum radiation direction on theradiation effect, and the direction of the ideal point source phase ratio, input power amplifying multiples.

In six, the operating frequency of the antenna range ( band width ) either the transmitting antenna andreceiving antenna, they are always in a certain frequency range ( band width ) working within the bandwidth of the antenna, there are two kinds of definitions - - - - - - a kind of means: in Bobbi SWR≤ 1.5conditions, the band antenna width; a means: the antenna gain deterioration within 3 dB bandwidth. In the mobiles communication system, usually in a defined, specifically, antenna band width is the antenna in Bobbi SWR is not to exceed 1.5, the operating frequency of the antenna range. Generally speaking, in theworking band width at different frequencies, the antenna performance is different, but the difference caused by the drop in performance is acceptable.

In seven, 3G related knowledge to introduce

What is the 3G license plate: wireless communication and Internet and other multimedia communications with a new generation of mobiles communication system the operating license. Like all sectors of thebusiness license, with the relevant departments of the state may operate the business license

Why do you want to 3G licences: according to the Chinese market, and promote China telecom marketcompetition; efficient utilization of frequency spectrum; code section, paragraph number will be from 15 to18; control operation cost, matter to our country the development of mobiles communications industry. Anyoperator wants to get 3G licence, should have five aspects: one is the network of strength strength. Two isin need of capital strength. Three is the technical strength. Four is the business strength. Five is userstrength. China Telecom, China Netcom, China mobiles, China Unicom PHS system. So you say is wrong,not include the question of who you said, surely this strength.

· 3G three standard

TD-SCDMA: Time Division - Synchronous CDMA ( full time division synchronous CDMA ), the standard isput forward by China 3G standard.

Features: the spectrum utilization rate of business support, flexibility and other advantages. Internet speedis four times of CDMA1X, free T network and G conversion.

WCDMA: also known as WCDMA, called Wideband CDMA, also known as CDMA Direct Spread, meaning for wideband code division multiple access, which is based on GSM network developed by the 3G specification, is put forward by Europe broadband CDMA technology.

Features: high spread spectrum gain, development space is larger, global roaming capability is the strongest, but mature technology in general.

CDMA2000:CDMA2000 is by a narrow band of CDMA ( CDMA IS95 ) technology from the development ofbroadband CDMA technology, also known as CDMA Multi-Carrier, the United States of North Americacompany led by high raised, South Korea has now become the standard leader.

Features: from the original CDMAOne structure directly upgrade to 3G, low construction cost.

Global 3G development condition: there are 67 3G network commercial, as of August this year, 45 countries had issued 146 permits, is available now is the 138

In eight, telecommunications technology noun explains: what is CDMA and CDMA2000 CDMA ( Code-Division Multiple Access ) is a CDMA technology, in recent years in the digital mobiles communicationprocess of a kind of advanced wireless spread spectrum communication technique, it can meet the needs of the market for mobiles communication capacity and high quality requirements, has a high utilization of the spectrum, voice quality, strong confidentiality, call drop rate low, small electromagnetic radiation, large capacity, overlying coverage is wide wait for a characteristic, can reduce investment and reduce operation cost. CDMA is the earliest by American Qualcomm Corp, similar to GSM, CDMA also has 2 generation, 2.5generation and 3 generation technology. China Unicom will in the second half of this year launched the CDMA belongs to the 2.5 generation technology. CDMA is considered as the third generation of mobiles communication technology of choice, the current standard of WCDMA, CDMA2000, TD-SCDMA.

What is CDMA2000? CDMA2000 is the TIA standard is used to refer to the third generation of CDMAname. Applicable to 3G CDMA TIA standard known as IS-2000, the technology itself is called CDMA2000.The first stage of CDMA2000 called 1X, which have the existing IS-95 system communication companyoverall system capacity can be doubled, and can increase the data rate to as high as 614kbps. Higher than a 1x CDMA2000 technology progress including 1xEV ( high data rate ). By QCT launched MSM5000 chip CDMA2000 solutions ( IS-95 CDMA ) cdmaOne downwardly compatible. The CDMA2000 standard adopted by 3GPP2, version 0, Release A including Release, EV-DO and EV-DV, Release 0 's main feature is theuse of ANSI-41D based core network, the wireless access network and core network to increase support for packet network entity, this version has stabilized. Link to the opening of the CDMA two phase of the project is used in this version, single carrier maximum downlink rate can reach 153.6kbit/s. Release A isRelease 0 strengthen, single carrier can reach a top speed of 307.2kbit/s, and support for voice and packet service concurrency. EV-DO uses a separate carrier support data service, can be in the 1.25MHz standardcarrier, while providing the voice and high speed packet data service, the highest rate of up to 3.1Mbit/s.

What is 3G :3G, refers to the third generation digital communication. Published in 1995, the first generationanalog mobiles phones ( 1G ) only for voice calls; 1996 to 1997 of the second generation of GSM, TDMA and other digital formats mobiles phones ( 2G ) increased the function of receiving data, such as receiving email or webpage; the third generation and the two generation is the main difference between the voice and data transmission speed the upgrade, it can be on a global scale to better achieve the seamless roaming, and processing the images, music, video and other forms of media, including the webpage browsing,conference calls, e-commerce and other information services, but also to consider and had second generation system compatibility. In order to provide this service, wireless network must be able to supportdifferent data transmission speed, that is to say in the indoor, outdoor and running environment to support at least 2Mbps ( megabits / second ), 384kbps ( kbit / sec ) and the transmission rate of 144kbps. ( this value according to the network environment will change ).

The so-called 3G standard, the International Telecommunications Union ( ITU ) is currently a total of four of the world's largest 3G standards were identified, they were WCDMA, CDMA2000 and TD-SCDMA and WiMAX. Where TD-SCDMA is the Chinese independent research and proposed 3G standard.