02.2-WCDMA RNP Antenna Selection_20051214

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WCDMA RNP Antenna

Transcript of 02.2-WCDMA RNP Antenna Selection_20051214

  • Antenna Selection

  • ReviewAntenna is the interface between a radio transceiver and outside propagation environment. The same set of antenna can both transmit and receive radio waves. When transmitting radio waves, it converts the RF currents into electromagnetic (EM) waves; when receiving radio waves, it converts EM waves into RF currents.

  • ObjectivesLearn the classification of antenna Know some of characteristics of antenna Study the principles for antenna selection Understand the antenna usage at different scenarios By this course, you will be able to:

  • ContentsAntenna ClassificationMajor Technical Performances of the AntennaPrinciples for Antenna Type SelectionAntenna Selection for Different ScenariosSummary

  • Based on the polarization mode: vertical polarization antennas (also called mono-polarization antennas) Cross polarization antennas (also called dual polarization antennas). Antenna Classification vertical polarization antennadual polarization antenna

  • Antenna Classification According to the outlines whip antennaplate antenna cap antennaparaboloid antenna

  • ContentsAntenna ClassificationMajor Technical Performances of the AntennaPrinciples for Antenna Type SelectionAntenna Selection for Different ScenariosSummary

  • Working Bands

    in China and EuropeUL: 1920 ~ 1980 MHzDL: 2110 ~ 2170 MHz in North AmericaUL: 1850 ~ 1910 MHzDL: 1930 ~ 1990 MHz

  • Antenna Gain Gain is one of the most important indices of an antenna. It indicates the antennas capability of centralizing energy to a certain direction dBi is defined as the energy centralizing capability of the actual directional antenna (including omni antenna) in relation to isotropic antennas, i means isotropic.

    dBd is defined as the energy centralizing capability of the actual directional antenna (including omni antenna) in relation to dipole antennas, d means dipole.

  • Antenna Gain As a passive device, antenna itself cannot increase the energy of transmitted signals. It only can centralize the energy to a certain direction by combining the antenna dipoles and changing their feeding mode

  • Antenna Pattern The graph describes the distribution of EM field of the antenna transmission along the fixed distance on the angular coordinates is called pattern. A pattern presented by transmission field intensity is called field intensity pattern, a pattern presented by power density is called power density pattern, and a pattern presented by phase is called phase pattern.

  • Antenna PatternSymmetric half-wave dipole PatternTop view side view directional antenna pattern omni antenna pattern

  • Antenna Pattern Beam width (BW) (called semi-power angle) Front-to-back ratio Zero-point filling Upper side lobe suppression

  • Relationship between Wave Width and Gain

    Antenna is an energy-centralizing device. The enhancement of transmission in one direction means the reduction of transmission in other directions. In general, we can enhance the transmission strength in a certain direction by reducing the horizontal lobe width so as to increase the antenna gain. Under a given antenna gain, the horizontal BW is in reverse proportion with the vertical BW: Ga : antenna gain, dBi;B: vertical BW, degree . : horizontal BW, degree.

  • Polarization Mode

    Polarization is the transmission performance describing the vector direction of EM field intensity. Unless specific state, the space direction of electric field vector is the polarization direction of EM wave. The vector direction refers to the direction of maximum transmission of antenna. Single polarization antennas in WCDMA system adopt vertical polarization, while dual polarization antennas use polarization diversity to minimize the negative effect of multi-path fading in the mobile communication system so as to improve the quality of receiving signals. Dual polarization antennas in WCDMA system usually use 45 cross polarization mode.

  • Mechanical Down Tilt and Electric Down Tilt Mechanical down tilt electric down tilt

  • Voltage Standing Wave Ratio (VSWR)

    When the input impedance is not consistent with the characteristic impedance, the reflected wave and the incident wave overlap on the feeder and form standing wave. The ratio between the maximum value and the minimal value of the adjacent voltage is VSWR. Big VSWR leads communications distance shortened, at same time reflection power returns to power amplifier (PA) of transmitter. PA might be damaged.

  • Voltage Standing Wave Ratio (VSWR)9.5 WIf and respectively stand for the input impedance and

    nominal impedance of the antenna, the reflectance is

    where . The matching feature of a

    port can also be indicated by Reflection Loss. If

    will be 13.98

  • Other Technical Performances

    Port Isolation Power Capacity Input Interface of the Antenna Passive Inter-modulation (PIM) Antenna Size and Weight Wind Load Working Temperature and Humidity Lightning Protection Three-Proof Capability

  • ContentsAntenna ClassificationMajor Technical Performances of the AntennaPrinciples for Antenna Type SelectionAntenna Selection for Different ScenariosSummary

  • Antenna Working Bands Outdoor Antennas Both WCDMA and DCS systems simultaneously 1710 ~ 2170 MHz Only for WCDMA system 1920 ~ 2170 MHz Indoor Antennas for GSM/DCS/WLAN/WCDMA 800 ~ 2500 MHz

  • Principle for Antenna Beam Width Selection Selection of beam width horizontal beam : depends on the type design of NodeB vertical beam: depends on antenna gain In urban areas 3-sector vertex-excited NodeBs, 65 horizontal beam width 6-sector vertex-excited NodeBs, 33 horizontal beam widthIn suburbs 3-sector center-excited NodeBs, 90 horizontal beam width

  • Principle for Polarization Mode Selection open mountainous areas and rural areas. vertical single polarization antennas

    urban area dual polarization antennas

  • Principle for Downtilt Mode Selection Comparison between Mechanical Downtilt and Electric Downtilt

  • Principle for Downtilt Mode Selection Comparison between Preset Electricity Downtilt and Zero-Point FillingThe use of preset electric downtilt can shorten the coverage range of the main lobe if the cell coverage is planed to small.

    Through zero-point filling, a kind of shaping technology, we can obtain a good pattern. In this case, the upper side lobe can be suppressed, so this kind of antennas will influence other aspects

  • Principle for Downtilt Mode Selection Planning and Optimization of Downtilt AngleFor an omni antenna, we cannot adjust the mechanical downtilt angle, but we can select preset electricity downtilt angle antennas.For a directional antenna, in different occasions, requirements for the downtilt angle adjustment range are different.

  • Principle for Front-to-back Ratio SelectionIn occasions where NodeB sites are densely distributed, if the back lobe is too big, it will be likely to cause pilot pollution and the network quality will be influenced. In urban areas, the antenna front-to-back ratio should be 25dB. In suburbs or rural areas, the antenna front-to-back ratio can appropriately lower. The front-to-back ratio is in reverse proportion to the beam width. The narrower the beam is, the higher the front-to-back ratio is.

  • Principle for Antenna Size Selection Antenna size selection is mainly related to the installability Firstly, the antenna size is related to the technical level of manufacturers Secondly, the antenna size is related to the antenna gain

  • Principle for Antenna Impedance Selection The input impedance of a combiner is 50. In order to reduce the standing wave ratio, the characteristic impedance of an antenna should match with the input impedance, namely, it should be 50. In general, the characteristic impedance can meet this requirement, but attention should be paid to this index during selection or certification of new antennas.

  • ContentsAntenna ClassificationMajor Technical Performances of the AntennaPrinciples for Antenna Type SelectionAntenna Selection for Different ScenariosSummary

  • Antenna Selection for Different Scenarios In WCDMA system, antenna selection is of great importance. Antennas should be selected based on the practical situations such as the NodeB design, network coverage requirements and interference conditions. Practical situationsIn urban coverageIn sub-urban coverageIn rural coverageIn highway coverageIn indoor coverageIn offshore coverageIn tunnel coverage

  • Antenna Selection for Different Scenarios In Urban CoverageHuawei Recommendation Frequency range: 1710 ~ 2170 MHz/45dual polarization / 65horizontal BW/15 dBi gain/preset 6electrical DT or 0 ~ 10adjustable electrical DT and 0 ~ 15 adjustable mechanical DT/upper side lobe suppression and zero-point filling/25dB or higher front-to-back ratio.

  • Antenna Selection for Different Scenarios In Suburban CoverageHuawei Recommendation: Select the specific antennas by referring to antenna selection for urban areas and that for rural areas depending on the distance between two NodeBs.

  • Antenna Selection for Different Scenarios In Rural CoverageRecommendation (for directional antennas): Working frequency 1710 ~ 2170 MHz / vertical polarization / 90 horizontal beam width / 18 dBi antenna gain / without preset downtilt / zero-point fillingRecommendation (for omni antennas): Working frequency 1710 ~ 2170 MHz / vertical polarizati