03 WCDMA RNP Antenna Principle and Selection

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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential

WCDMA RNP Antenna Principle and Selection

Internal


Review

Interface between radio transceiver and outside

propagation environment.

Antenna can transmit and receive radio waves.

Converts the RF currents to electromagnetic (E

M) waves;

Receives radio waves, and converts EM waves t

o RF currents.


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:


Contents

Antenna Principle and Classification

Primary Technical Performances of the Antenna

Rules for Antenna Type Selection

Antenna Selection for Different Scenarios

Summary


Antenna location and function

Antenna and feeder system 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 window

NodeB


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


Antenna Classification According to radiation direction


According to polarization direction:

Antenna polarization direction: electric field vector is the

polarization direction of EM wave

Antenna Classification

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 an

antenna. It indicates the antenna’s 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 ¸ Isotropic

Dipole

Actual antenna

The actual antenna gain is 11dBi

11dBi

8.85dBd 2.15dB 2.15dBi ERP

EIRP


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 power density is called power density pattern,

and a pattern presented by phase is called phase

pattern.

Normally power density pattern is used in Mobile

communication system, it includes vertical pattern

graph and horizontal pattern graph


Symmetric half-wave dipole PatternTop view side view

directional antenna pattern omni antenna pattern

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:

10 lg 32400aG Ga : antenna gain, dBi;B: vertical BW, degree .Θ : 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.


Polarization Mode 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.

+/- 45°)


Mechanical Down Tilt and Electric Down Tilt 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.


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

AoZ

oA

oA

1

1VSWR

50oZ

1:5.1VSWR

dBLR ..

. .( ) 20 lgR L dB


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


Contents





Summary


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 width

In suburban areas

3-sector center-excited NodeBs, 90° horizontal

beam width


Principle for Polarization Mode Selection

urban area

dual polarization antennas

open mountainous areas and rural

areas

vertical single polarization antennas


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


Principle for Downtilt Mode Selection Comparison between Preset Electricity Downtilt and Zero-Point FillingComparison between Preset Electricity Downtilt and Zero-Point Filling

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.


Principle for Downtilt Mode Selection

Planning and Optimization of Downtilt AnglePlanning and Optimization of Downtilt Angle

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.


Principle for Front-to-back Ratio Selection

In 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 Antenna size selection is mainly

related to the install abilityrelated to the install ability

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 50Ω. In

order to reduce the standing wave ratio, the

characteristic impedance of an antenna should

match with the input impedance, namely, it

should be 50Ω.

General, the characteristic impedance can

meet this requirement, but attention should be

paid to this index during selection or

certification of new antennas.


Contents





Summary



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


In Urban CoverageIn Urban Coverage

Huawei Recommendation

Frequency range: 1710 ~ 2170

MHz/±45°dual polarization / 65°horizontal

BW/15 dBi gain/preset 6°electrical DT or 0

~ 10°adjustable 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 ScenariosAntenna Selection for Different Scenarios


In Suburban CoverageIn 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.



In Rural CoverageIn Rural Coverage

Recommendation (for directional

antennas): Working frequency 1710 ~ 2170

MHz / dual or vertical polarization / 90°

horizontal 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-point filling



In Highway CoverageIn 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 70° horizontal beam

width / 14 dBi antenna gain / without preset

downtilt / zero-point filling



For Highway CoverageFor Highway Coverage

Recommendation (for heart-shape

antennas):

Frequency range: 1710 ~ 2170 MHz/VP/2

10°horizontal BW / 12 dBi gain / without preset

DT

zero-point filling

S0.5/0.5 NodeB configuration with high-gain

directional antennas

8-figure-shape antennas



In Indoor CoverageIn Indoor Coverage Recommendation (for omni antennas):

Frequency range: 800 ~ 2500 MHz/vertical

polarization

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

Recommendation (for plate directional

antennas): Frequency range: 800 ~ 2500

MHz/vP/90°horizontal BW, 60°vertical BW/7dBi gain.

Recommendation (for log-periodical antennas):

Frequency range: 800 ~ 2500 MHz/VP/55°horizontal

BW, 50° vertical BW/11.5dBi gain.



In Offshore CoverageIn Offshore Coverage

Antenna Recommended:

frequency range: 1710 ~

2170 MHz

vertical polarization

30° horizontal BW

gain 21 dBi

without preset DT

zero-point filling



In Tunnel CoverageIn Tunnel Coverage

Antenna Recommended

Frequency range: 800 ~ 2200 MHz

vertical polarization

55°/30°horizontal BW

log-periodical type with gain 11.5 dBi

(consider sharing with GSM/DCS

systems).

Leaky cable



Contents


Major Technical Performances of the Antenna

Principles for Antenna Type Selection


Summary


Summary

This course helps us: To master antenna principle and classification

To master parameters of antenna

To understand the principles of antenna selection

To select antenna focusing on specific working

environments

Thank youwww.huawei.com

03 WCDMA RNP Antenna Principle and Selection

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