03 WCDMA RNP Antenna Principle and Selection

5/21/2018 03 WCDMA RNP Antenna Principle and Selection

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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 1

WCDMA RNP Antenna

Principle and Selection

Internal


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Review

Interface between radio transceiver and outsidepropagation environment.

Antenna can transmit and receive radio waves.

Converts the RF currents to electromagnetic (EM)

waves;

Receives radio waves, and converts EM waves

to RF currents.


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Objectives

Learn the principle and classification of

antenna

Know some of characteristics of antenna

Study the rules for antenna selection

Understand the antenna selection for different

scenarios

From this course, we will be able to:


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Contents

Antenna Principle and Classification

Primary Technical Performances of the Antenna

Rules for Antenna Type Selection

Antenna Selection for Different Scenarios

Summary


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Antenna location and function

ntenna and feedersystem figure

Thunder

protector

Feeder(7/8)

Feeder

clip

Feeder

ladder

Grounded

clip

Connector, insulated airproof

tape, PVC insulated tape

Adjustable

support

Board

antenna

Pole(50~114mm)

Outdoor

jumper

Indoor jumper

Feeder

windowNodeB


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Based on the polarization mode:

Alternant circuit in the lead will radiate electromagnetic (EM) waves, the

radiation ability is related to the length and shape of lead.

When the length of lead is close to wave length, circuit in the lead will

increase greatly and radiate strong radio wave, we call this direct lead as

pole.

Antenna Work Principle

positive

negative


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Antenna Classification

According to radiation direction



According to polarization direction:

Antenna polarization direction: electric field vector is the polarization

direction of EM wave


vertical polarization horizontal polarization

+45 polarization -45 polarization



According to polarization mode:vertical polarization antennas (also called mono-polarization

antennas)

Cross polarization antennas (also called dual polarization

antennas).


single polarization (vertical) antennadual polarization(+-45) antenna




According to the outlines

whip antenna plate antenna cap antenna paraboloid antenna



Contents

Antenna Classification and Classification

Primary Technical Performances of Antenna



Summary



Working Bands

in China and Europe

UL: 1920 ~ 1980 MHz

DL: 2110 ~ 2170 MHz

in North America

UL: 1850 ~ 1910 MHz

DL: 1930 ~ 1990 MHz



Antenna Gain

Gain is one of the most important indices of anantenna. It indicates the antennas capability of

centralizing energy to a certain direction

dB iis defined as the energy centralizing capability of the

actual directional antenna (including omni antenna) in

relation to isotropic antennas, i means isotropic.

dBdis defined as the energy centralizing capability of the

actual directional antenna (including omni antenna) in

relation to dipole antennas, d means dipole.


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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 IsotropicDipole

Actual antenna

The actual antenna gain is 11dBi

11dBi

8.85dBd 2.15dB 2.15dBi ERP

EIRP


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Antenna Pattern The graph describes the distribution of EM field of the

antenna transmission along the fixed distance on the

angular coordinates.

A pattern presented by transmission field intensity is

called field intensity pattern, a pattern presented by powerdensity is called power density pattern, and a pattern

presented by phase is called phase pattern.

Normally power density patternis used in Mobile

communication system, it includes vertical pattern graph

and horizontal pattern graph


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Symmetric half-wave dipole Pattern

Top view side view

directional antenna patternomni antenna pattern

Antenna Pattern


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Antenna Pattern

Beam width (BW) (called semi-power angle)

Front-to-back ratio Zero-point filling

Upper side lobe suppression


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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 toincrease the antenna gain. Under a given antenna gain,

the horizontal BW is in reverse proportion with the

vertical BW:

10 lg 32400

a

G Ga : antenna gain, dBi;

B: vertical BW, degree .

: horizontal BW, degree.


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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.


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Polarization Mode

Single polarization antennas in WCDMA system adopt vertical

polarization, while dual polarization antennas use polarizationdiversity 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.

+/- 45)


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Mechanical Down Tilt and Electric Down Tilt

Mechanical down tilt

electric down tilt


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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 theadjacent 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.


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9.5 W80

ohms50 ohms

Forward: 10W

Reflection: 0.5W

Voltage Standing Wave Ratio (VSWR)If 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

A

oZ

oA

oA

1

1VSWR

50oZ

1:5.1VSWR

dBLR ..

. .( ) 20 lgR L dB


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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


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Contents





Summary


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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


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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 beamwidth

6-sector vertex-excited NodeBs, 33 horizontal beamwidth

In suburban areas

3-sector center-excited NodeBs, 90 horizontal beam


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Principle for Polarization Mode Selection

urban area

dual polarization antennas

open mountainous areas and rural areas

vertical single polarization antennas


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Principle for Downtilt Mode Selection

Comparison between Mechanical Down ti l t and Electr ic Downti l t


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Principle for Downtilt Mode SelectionComparison between Preset Electr ic i ty Downti l t and Zero-Point Fi l l ing

The 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.


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Principle for Downtilt Mode Selection

Plann ing and Optim izat ion of Downti l t An gle

For 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.


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Principle for Front-to-back Ratio Selection

In occasions where NodeB sites are densely distributed, ifthe 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.


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Principle for Antenna Size Selection

Antenna size selection is mainly related

to the install ability

Firstly, the antenna size is related to thetechnical level of manufacturers

Secondly, the antenna size is related to

the antenna gain


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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.

General, the characteristic impedance can meet this

requirement, but attention should be paid to this

index during selection or certification of new

antennas.


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Contents





Summary



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Antenna Selection for Different Scenarios In WCDMA system, antenna selection is very important. Antennas

should be selected based on the practical situations such as the

NodeB design, network coverage requirements and interference

conditions.

Practical situations

In urban coverage

In sub-urban coverage

In rural coverage

In highway coverage

In indoor coverage

In offshore coverage

In tunnel coverage


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In Urban Coverage

Huawei Recommendation

Frequency range: 1710 ~ 2170 MHz/45dualpolarization / 65horizontal BW/15 dBigain/preset 6electrical DT or 0 ~ 10adjustableelectrical DT and 0 ~ 15 adjustable mechanicalDT/upper side lobe suppression and zero-pointfilling/25dB or higher front-to-back ratio.



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In Suburban Coverage

Huawei 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 and traffic density.



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In Rural Coverage

Recommendation (for directional antennas):

Working frequency 1710 ~ 2170 MHz / dual or vertical

polarization / 90horizontal beam width / 18 dBi

antenna gain / without preset downtilt / zero-point filling

Recommendation (for omni antennas):Working

frequency 1710 ~ 2170 MHz / vertical polarization / 11

dBi antenna gain / without preset downtilt / zero-pointfilling



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In Highway Coverage

Recommendation (for directional antennas):Working

frequency 1710 ~ 2170 MHz / vertical polarization / 30

horizontal beam width / high gain (for example: 21 dBi) /

without preset downtilt / zero-point filling

Recommendation (for 8-figure-shape antennas):

Working frequency 1710 ~ 2170 MHz / vertical

polarization / dual 70horizontal beam width / 14 dBi

antenna gain / without preset downtilt / zero-point filling



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For Highway Coverage Recommendation (for heart-shape antennas):

Frequency range: 1710 ~ 2170 MHz/VP/2

10

horizontal BW / 12 dBi gain / without preset DTzero-point filling

S0.5/0.5 NodeB configuration with high-gain directional

antennas

8-figure-shape antennas



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In Indoor Coverage

Recommendation (for omni antennas):

Frequency range: 800 ~ 2500 MHz/vertical polarization

(VP)/360horizontal BW, 90vertical BW/2dBi gain.

Recommendation (for plate directional antennas):

Frequency range: 800 ~ 2500 MHz/vP/90horizontal BW,

60vertical BW/7dBi gain.

Recommendation (for log-periodical antennas):

Frequency range: 800 ~ 2500 MHz/VP/55horizontalBW,

50vertical BW/11.5dBi gain.



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In Offsho re Coverage

Antenna Recommended:

frequency range: 1710 ~ 2170 MHz

vertical polarization

30 horizontal BWgain 21 dBi

without preset DT

zero-point filling



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In Tunnel Coverage

Antenna Recommended

Frequency range: 800 ~ 2200 MHz

vertical polarization55/30horizontal BWlog-periodical type with gain 11.5 dBi

(consider sharing with GSM/DCS systems). Leaky cable



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Contents


Major Technical Performances of the Antenna

Principles for Antenna Type Selection


Summary


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Summary

This course helps us:

To master antenna pr inciple and c lassi f icat ion

To master parameters of antenna

To understand the pr inciples of antenna select ion

To select antenna focus ing on speci f ic working

envi ronments


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03 WCDMA RNP Antenna Principle and Selection

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