omp110030 antenna basics issue1.01

7/30/2019 OMP110030 Antenna Basics ISSUE1.01

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Confidential Information of Huawei. No Spreading Without Permission

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Copyright 2009 Huawei Technologies Co., Ltd. All rights reserved.

Antenna Basics


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Page2Copyright 2009 Huawei Technologies Co., Ltd. All rights reserved.

Foreword

z Antenna is most basic and important equipment is radio

network. The specification and selection of antenna is very

important for network QoS.


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Contents

1. Antenna Fundamentals

2. Antenna Working Principle

3. Antenna Specifications

4. Antenna Selection

5. Electric Downtilt Antenna


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Contents







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Contents


1.1 Overview

1.2 Antenna type

1.3 Polarization


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Overview

Lightning

Arrester

Main Feeder 7/8

Feeder

Clip

Feeder

Support

Grounding

Point

Antenna Adjustable Support

GSM/CDMA

Panel Antenna

Holding Pole ( 50~114)

BTS

Wall

z In a wireless telecommunication system, the antenna provides the interface between base

transceiver station (BTS) and outside propagation mediums. One set of antenna can both

radiate and receive radio waves. When radiating radio waves, it converts high frequency

current into electromagnetic wave; when receiving radio waves, it converts the

electromagnetic wave into high frequency current.

z During network planning, the right antenna is selected according to the radio environment

of the BTS. The parameters, such as antenna height, antenna azimuth angle, tilt angle, are

decided based on the selected antenna.

z Antenna is directly related to uplink and downlink converges, so are the radio frequency

(RF) components, such as feeder cable, combiner, and duplexer.


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Contents


1.1 Overview

1.2Antenna type

1.3 Polarization


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Antenna Type

z Vertical polarization antenna

(unipolarization antenna)z Cross polarization antenna

(dual polarization antenna)

Polarization way

z Linear antennaz Panel antennaz Cap antenna

Structural feature

z Omni-directional antennaz Directional antenna

Radiation direction

TypeDivisionstandard


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Antenna Type By Structure

Plate-shape antenna Cap-shape antenna

Whip-shape Paraboloid antenna


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Antenna Type By Polarization

Omni antennaUni-polarization

Directional antenna

Dual polarizationDirectional antenna


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Contents


1.1 Overview

1.2 Antenna type

1.3 Polarization


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Polarization (Cont.)

z In electromagnetic wave radiated by antenna, the direction ofelectric field vector is the direction of antenna polarization.

Horizontal PolarizationVertical Polarization

+45o Polarization -45o Polarization

z Polarization is a radiation feature describing the direction for the field strength vector of

electromagnetic wave. Generally, the direction of the field strength vector works as the

polarization direction of the electromagnetic wave.

z The electromagnetic wave with the direction of the electric field vector unchanged at any

time is called linear polarized wave. If the land is taken as a reference, the direction of the

electric field vector parallel to the land is called horizontal polarized wave; the direction of

the electric field vector perpendicular to the land is called vertical polarized wave.

z The direction of the electric field vector is changeable. If the trace of the electric field

vector end is a circle, the electromagnetic wave is called circular polarized wave; if the

trace is an ellipse, the electromagnetic wave is called ellipse polarized wave. Both the

circular polarized wave and ellipse have a feature, which is rotating phase.

z The electromagnetic waves of different bands are transmitted by different polarization

modes. Generally, the vertical polarization is used in mobile communication; the horizontal

polarization is used in broadcasting systems; and the ellipse polarization is used in satellite

communication.


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Polarization

z Two antenna combined together, transmit and receive twoindependent wave.

+ 45 / - 45 Polarization0 / 90 Polarization

z The GSM antenna can be divided into two types, namely, single polarization antenna and

dual polarization antenna. With the help of polarization diversity technology, a dual

polarization antenna can promise BTS to receive good signals through reducing the multi-

path effect in mobile communication. Two specifications, 0/90 and 45 are

available to the dual polarization antenna.


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Polarization Loss

z When polarization direction of transmited wave and receivingantenna is different, there will be a Polarization Loss during

receival.

z Linear Polarization wave will take 3dB loss when received by

Circular Polarization antenna.

z Horizontal Polarization antenna can not receive the energy

from Vertical Polarization wave.

In practical Network, you may find such phenomenon: sometimes when cell phone is

vertical( phone on ear side), signal is stronger; when cell phone is horizontal( use

earphone), signal is weaker. Think about why?


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Antenna Radiation (Cont.)z

According to Maxwellequation, electromagnetic

wave radiation can be

generated if alternate

current is present in the

conductor. The radiation

capability is related to the

length and shape of the

conductor.

AA

CC

BB

z As shown in Figure (a), when the distance of the two conductors is short, the induced

electromotive force generated on the ideal conductors will counteract the effect of each

other, so only a small amount of energy is radiated beyond the two conductors.

z As shown in Figure (b), there is a flare angle between the two conductors. Because the

current is generated in the same direction, the induced electromotive force is generated in

the same direction. In this case, a larger amount of energy is radiated beyond the two

conductors.

z As shown in Figure (c), when the flare angle is wide enough to match wavelength, the

amount of current flowing through the conductors will be greatly increased. Thus intensive

radiation is generated.

.


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Antenna Radiation (Cont.)

z The straight conductor that can generate intensive radiation iscalled dipole.

z If the length of the two arms of a dipole is 1/4 wavelength, the

dipole is calledsymmetrical dipole

Dipole

1/2

1/4

1/4

1/2

Wavelength( )

900MHz900MHz -->> : 166mm: 166mm

1800MHz1800MHz -->> : 83mm: 83mm


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z Symmetry Dipole Radiation

Side view

Top view

ConcentrationConcentration


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1mW by one dipole 4mW by array of four dipole

6dB Gain6dB Gain


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z By reflection, radiation energy can be concentrated tosingle direction.

Omni: 4mW Directional: 8mW

Antenna(Top View)

9dB Gain9dB Gain6dB Gain6dB Gain


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Antenna Radiation

z The more the dipole in one

antenna, the more

concentrated the radiated

energy, the higher the

Antenna Gain.

z From one dipole to nine

dipole, Antenna Gain

increase from 0 to 9dBd.


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Electric Specifications


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Frequency Range (Cont.)

z Frequency Range is also calledAntenna Bandwidth.

z Antenna works in specific range frequency. The Central

Frequency (fc) have the best performance, deviation offc

deteriorate the performance.

z Two definition ofAntenna Bandwidth: 3dB deterioration of

Antenna Gain or VSWR too high, typically 1.5. The later one is

commonly used in wireless communication.


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Frequency Range

z Central Frequency850MHz is with best performance. But withinBandwidth 820MHz-890MHz, VSWR


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Directionality

z The Directionalityis the ability of Antenna to radiateelectromagnetic wave in a specific direction.

z As to receiving, it is the ability to receive signal from different

direction. Directionalityis represented byAntenna Pattern

Diagram.

z Antenna Pattern Diagram shows the transmitting and receiving

ability of antenna at different direction of space.


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Antenna Pattern (Cont.)

Horizontal patternHorizontal pattern

Main LobeMain Lobe

First SideFirst Side

LobeLobe

Back LobeBack LobeZero PointZero Point

Horizontal HalfHorizontal HalfPower BandwidthPower Bandwidth

--3dB3dB

Vertical patternVertical pattern

The radiation intensity of Antenna is related to radiation direction. If the relationship between

the two is drawn according to relative scale, it is an Antenna Pattern diagram, or radiation

diagram.

Three relative scales are available for drawing a directional diagram. They are:

z Linearity (power directional diagram)

z Square root (field strength diagram)

z Decibel

The decibel scale is more often used among the three, because it expresses the side lobe level

in a simpler way.

z The Antenna Pattern diagram is 3D figure, but the one in common use is a pattern

diagram within two planes perpendicular to each other, known as plane pattern diagram.

For the linear antenna, since the ground effect is great, it adopts the vertical plane and

horizontal plane as its principle plane. For the plane antenna, it adopts two planes, namely,

E plane and H plane.

z Essentially, the dipole arrangement and the change of the feeding phase of each dipole

work together to determine antenna direction, and the principle is similar to that of the

Light Interference Effect. Therefore, the energy in some directions is amplified, but the

energy in other directions is weakened. In this case, lobes (or beams) and zero points areformed. The lobe with the strongest energy is the major lobe. The lobe with the second

strongest energy is the first side lobe, and so on. For the directional antenna, it has a back

lobe.


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Antenna Pattern (Cont.)


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Antenna Pattern

The ratio of the maximum main lobe power to the

maximum back lobe power.Back lobe cause interference.

Front-to-back ratio

The ratio of the maximum main lobe power to the

maximum side lobe power.Side Lobe SuppressionRatio

Angle included by two direction of 3dB deterioration

than the max transmission direction.Horizontal half power Lobe width and vertical half

Lobe width.

Half Power Lobe Width

When zero depth is -20dB or greater, and theantenna is high, to ensure the coverage, zero point

filling is needed.Zero Point Filling

DescriptionDescriptionParameterParameter

z To make the Coverage better, the first zero point of the lower side lobe needs to be filled

by using the shaped-beam design. Generally, when the zero depth is -20dB greater than

the main beam, it means that the zero point filling is present in antenna.

z It is recommended that the zero point filling technology should be applied to high gain

antennas with great height (for example, the antenna height is 100 meters) to improve

nearby coverage and avoid the unequal coverage caused by signal fluctuation.


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Antenna Gain (Cont.)

z Antenna Gain is an important antenna index, indicating theantenna capability (directional antenna) of concentrating energy

into a certain direction.

Isotropic Antenna

Dipole Antenna

Practical Antenna

dBd

dBi

2.15dB

--70dBm70dBm--85dBm85dBm--87.15dBm87.15dBm

(15)(15)

(17.15)(17.15)

z The antenna is passive equipment, so the concept of antenna gain is different from that of

the power amplifier gain. The power amplifier can amplify power, but the antenna does

not increase the energy for radiated signals. It concentrates the energy into a certain

direction by assembling several antenna dipoles and changing their feeding mode.

z The dBi and dBd are two units of antenna gain, and the relationship between the two is as

follows:

z Where, dBi = dBd + 2.15

z The dBi indicates the energy concentration capability of the antennas with directions

(including omni antennas) as compared with that of the isotropic antennas. i stands for

isotropic.

z The dBd indicates that the energy concentration capability of the antennas with directions

(including omni antennas) as compared with that of the symmetrical dipole antennas. d

stands for dipole.


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Antenna Gain

z Relationship betweenAntenna Gain Ga, Horizontal Half PowerLobe Width and Vertical Half Power Lobe Width :

32400log10

aG

z One function of the antenna is concentrating energy, so if the radiation intensity in some

direction is strong; the radiation intensity in other direction is weak. Generally, the

radiation intensity in a direction can be enhanced through reducing the width of the lobes.

Another situation, when the antenna gain is certain, the antenna horizontal half power

angle is reversely proportional to the vertical half power angle.

z For example, there is an omni antenna. If the antenna gain is 11dBi, and the horizontal

half power angle is 360, the vertical half power angle is. Due to the difference of

antenna design and manufacturing, slight difference is present for the vertical half power

angle of the actual omni antenna. And such difference is determined by the focus and

implementation ways of the electrical design.

z When the antenna gain is small, the vertical half power angle and horizontal half powerangle are large; when the antenna gain is large, the vertical half power angle and

horizontal half power angle are small.

z In addition, the antenna gain depends on dipole quantity. The larger the dipole quantity,

the larger the antenna gain is, and the larger the antenna size. For example, for a 900MHz

omni antenna, if the antenna gain increases by 3dB, the antenna length doubles. Generally,

therefore, the gain of the omni antenna does not exceed 11dBi, and the antenna length

now is about 3 meters.


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Downtilt Angle

z Electric Downtilt and Mechanical Downtilt. Genarally, theformer is better, but more expensive.

1010oo

ElectricElectric 1010oo

MechanicalMechanical66oo

Electric +Electric +

44oo

MechanicalMechanical


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Others

Third-order Intermodulation product.

Two TRX use f1 and f2, both input power 43dBm. The Third-

order Intermodulation product is 2f1-f2 and 2f2-f1, the power ofwhich should be less than, for example, -150dBc or -107dBm.

IM3

The max average power capacity.

For example, a single carrier is 40W, one port input eight

carriers, the total input of the antenna is 320W. Therefore, thepower capacity of a single port must be greater than 320W.

Related to environmental temperature, typically tested under 50oC.

Power Capacity

For the antenna with multiple ports, such as dual polarization

antenna, the isolation between the ports for both transmission

and reception must be greater than 30dB

Port Isolation

DescriptionDescriptionParameterParameter


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Mechanical Specifications

z Input Connector Type

z Working Temperature

z Working Humidity

z Wind Load

z Size and Weight

Antenna size and weightz If all electric indicators are met, the antenna should be as small as possible in size and as light as

possible in weight for storage, transport, installation, and security purposes.

z Now carriers have higher requirements on antenna size, weight, and shape. Therefore, both

technical indicators and the previous non-technical factors must be emphasized in antenna

selection. Generally, the antenna installed in urban area should be small, light, and eye catching.

Wind loadingz The base station antenna must be installed on the top of high buildings and towers. In coastal

areas, where the wind is strong all the year around, so it is required that the antenna can work

normally against the wind at the speed of 36m/s and are not damaged when the wind speed

reaches 55m/s.

z The antenna itself can stand strong wind. In areas where the wind is strong, the antenna is

damaged mainly because the tower or the supporting bar is damaged.

Work temperatire and humidity

z The base station antenna works normally when environment temperature ranges -40C to +65C

and environmental relative humidity ranges from 0 to 100%.

Lightning protectionz All RF input ports of the base station antenna are required to be directly grounded through direct

current.

Three proof capabilityz The base station antenna must have three proof capability, that is, moisture proof, salt

atmosphere proof, and mildew proof. For the omni antenna, it can be installed in reverse direction

according to installation instructions and the three proof requirements.


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Overview

z The antenna selection is very important. The selection shouldconsider actual conditions, such as coverage requirement, traffic

volume, interference, and QoS.

z Antenna selection is closely related to coverage, so the antenna

application can be divided into four types according to

landforms or traffic distribution: Urban area,Suburban area,

Rural area, and Road area.


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Problem in Antenna Selection

z Landforms and Antenna Pattern.

Blind under tower.Blind under tower.

z Large Mechanical Downtilt.

DistortionDistortion -->>

z High Gain Antenna.

Size, Zero Point, Side LobeSize, Zero Point, Side Lobe

z Polarization.

Loss.Loss.

InterferenceInterference

z The antenna is selected only based on the covered traffic distribution, but little

consideration is given to the relationship between landforms and antenna pattern diagram.

For example, if all antennas used in a network are of the same type, when the antenna is

installed at a high position, the phenomenon of "blind under tower will be present

because the width of the beams in vertical plane is narrow.

z Too large antenna mechanical tilt angle results in the distortion of the pattern diagram. In

this case, coverage problem or interference problem will occur. Emulation shows that the

restrictions on tilt angles must vary in accordance with the antennas with different gains.

z Too much attention is focused on the high gain performance of the antenna but little

attention is given to its drawbacks. As a result, the gains of almost all the antennas used in

a network are quite high. A high gain antenna has many drawbacks, including large size,great weight, high side lobe, deep zero lobe, and narrow vertical beams.

z No consideration is given to the difference between the vertical polarization antenna and

dual polarization antenna in terms of application. The dual polarization antenna is selected

from the perspective of installation.


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Downtilt Planning (Cont.)

z Downtilt Angle decided by Half Power Lobe Width ,Antenna High H and Coverage Distance D.

2)arctan( +=

DH

According to the technical performance of the antenna, the antenna gain decreases slowly

within half power angle, but it decreases sharply beyond the half power angle, especially

for the upper lobe. Therefore, when the antenna tilt angle is considered, the scope

between the extension line of the half power angle to intersection point (point B) can be

taken as the actual coverage area of the antenna.

z This formula can calculate the coverage distance after the adjustment for tilt angle. Actual

results of on-site optimization projects show that this formula is of great significance.

However, the application of this formula meets limited conditions. It can be applied when

the tilt angle is 1.5 times greater than the half power angle, and the distance (D) must be

less than the distance calculated by the formula when no tilt angle is present. For the

width of vertical beams in the formula, it is provided in the specific antenna technical

indexes.


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Downtilt Planning

23010001565 degrees, 15 dBi

10308001565 degrees, 15 dBi

12405001565 degrees, 15 dBi

12355001565 degrees, 15 dBi

11305001565 degrees, 15 dBi

10255001565 degrees, 15 dBi

17402501565 degrees, 15 dBi

15352501565 degrees, 15 dBi

14302501565 degrees, 15 dBi

DowntiltDowntilt AngleAngle

(degree)(degree)

AntennaAntenna

Height (m)Height (m)

CellCellradiusradius

R(mR(m))

Vertical HalfVertical Half

Power AnglePower AngleAntenna TypeAntenna Type

z According to the table, when the cell radius is small, the coverage area cannot be effectively controlled even

through mechanically tilting the antenna. In this case, the coverage area can be controlled through lowering

the antenna height only. If it is hard for the antenna height to be lowered, the antenna electrical tilt together

with the antenna mechanical tilt must be used.

z The previous methods for calculating tilt angles are mainly applicable for the dense base station networking

with the distance within 1200 meters (that is, R = 800 meters) between stations.

z When the distance from the base station to the coverage target is greater than 800 meters, large area

coverage is still being emphasized. In this case, it is unnecessary for you to consider the effect of the vertical

half power angle when estimating the antenna tilt angle. Generally, the tilt angle now is 1 degree to 4

degrees.

z However, because the environment around the base station is rather complicated, the reflection caused the

nearby mountains, water surface, huge glass walls has an effect on antenna tilt angle. The reflection of this

kind will easily cause unexpected interference against the neighbor frequencies and time dispersion effect. In

addition, the shadow effect caused by building roofs, front dense buildings and mountains must be alsoconsidered. In actual networking, however, geographic environment, such as the barrier of high buildings and

mountains, around the base station can be used to control coverage area.

z When a network is implemented in a populated urban area, the major lobe of the antenna cannot be directly

parallel to the street, or waveguide effect will easily occur. In this case, it is rather hard to prevent cross

coverage. When a cell is required to cover the area above the antenna height, you can use a directional

antenna and uplift this antenna.

z The effect of the antenna back lobes must be also considered. Generally, the front-to-back ratio of the

antenna is about only 20dB, so the back lobes with strong signals will cause much interference against high

building coverage. As a result, it is recommended that electrical tilt antennas should be used in populated

urban areas, it reduce back lobes. In addition, the effect of the upper side lobe must also be considered.


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Urban Area

Sites are very dense in urban areas. The coverage area of each cell should be assmall as possible to reduce interference and enhance frequency reuse.

Consider the limited space in cities, DualPolarization Antenna is prefered.

Antenna Polarization

medium gain 15dBi (900MHz) and 15-18dBi (1800 MHz)

Antenna Gain

z Should be smaller value, 65typically.

z Proper selection can reduce interference

Horizontal Half PowerLobe Width:

RequirementRequirementParameterParameter

z Because a large number of base stations are distributed in urban areas, overlapping coverage and

frequency interference rises as serious problems in a network. To reduce the overlapping areas of

neighbor sectors and the interference between base stations, you can set the beam width of theantenna horizontal half power to a smaller value. Generally, antennas whose horizontal half power

beam width is 65 are selected.

z The base stations in urban areas are not required to cover a large area, so the antennas with

medium gain are recommended. Thus the antenna vertical beam can be wider, which can improve

the coverage quality within the areas to be covered. In addition, the size and weight of the antenna

with medium gain are small, which is helpful for installing the antenna and reducing cost. According

to present antenna specifications, antennas with a gain of 15dBi (900MHz) and 15-18 dBi (1800

MHz) are recommended in urban areas.

z

For the base stations on the outskirt of a city, if it is required to cover a large distance, you canselect the antennas with higher gains, such as 17dBi and 18dBi.

z In urban areas, to enhance frequency reuse rate and reduce cross interference, you can select the

shaped-beamed antenna with the first upper side lobe suppressed and the lower side lobe filled.

z Because space restriction is present in the antenna installation in urban areas, the dual polarization

antenna is recommended. And it is better to select the antenna with a smaller size when the

electrical specifications of the antennas are the same or nearly the same.


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Suburban Area

Because the environment is suburban areas are largely different from that of urban

areas, antennas used in suburban areas can be selected according to the required

coverage area.

Omni antennas are not recommended for smooth

expansion in the future. Antenna type

z 65 or 90 can be selected

z According to actual conditions.

Horizontal Half Power

Lobe Width:


z The antennas whose horizontal half power beam width is 65 or 90 can be selected

according to actual conditions. If base stations are sparsely distributed, the antennas

whose horizontal half power beam width is 90 is first considered.

z If the base stations are densely distributed, the antennas are selected by referring to the

principles for selecting base station antenna in urban areas.

z Omni antennas are not recommended for the purpose of smooth expansion in the future.


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Rural Area

z If directional antenna, 90 is recommended . Horizontal Half Power

Lobe Width:

In rural areas, traffic volume is small and base station are sparsely distributed, so

some base stations are required to cover a large area.

When high site for wide coverage, zero point filling

is necessary. Zero Point

Omni Antenna is recommended.

If for wide coverage, high gain directional antennais required.

Antenna type


z Considering the construction cost, you are recommended to select an omni antenna for

the base stations whose coverage area is small and traffic volume is low. However,

because the gain of the omni antenna is low, the coverage of an omni antenna is shorter

than that of a directional antenna. When the base station is required to cover a long

distance, the directional antenna must be selected to realize the coverage. Generally, a

high gain vertical polarization antenna whose horizontal half power beam width is 90

is recommended.

z One point needs to be noted. That is, if the base station antenna is installed at a high

position, but the area needs to be covered lies in a low location (the depression angle is

greater than 5), when an omni antenna is used, the kind with a preset tilt angle or

with zero point filling function are recommended to improve the coverage quality of this

area. In this case, the phenomenon of blind under tower and the signal fluctuation

caused by uneven coverage can be avoided.


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Road Coverage

z To cover the areas along railways and highroads, a directionalantenna with narrow beams can be selected.

z To cover the highroads and the villages scattered around the

highroads, an omni antenna can be selected.

z To cover highroads only, an 8-shaped antenna can be selected.

z To cover the highroads and the towns on one side of the

highroads, the 210antenna can be selected.


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Road Coverage (Cont.)


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Road Coverage


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Reference

zMoutain side, first consider the antennas with low gain and

wide vertical beams.

Directional

zMoutain top, first consider the antennas with zero point filling

function, and then consider the antennas with low gain.

Omni

Mountain

zFirst consider the 210 antennas, and then consider using the

directional antenna and omni antenna together.

Directional

+ Omni

zFirst select the 8-shaped antennas, it is preferred to have zero

point filling function.

Directional

Expressways

zSelect the antennas with zero point filling.Omni

zGenerally, select the 90 antennas.DirectionalPlains &

Rural

zGenerally, select the antennas with high gain; both electrical

and mechanical tilt antenna are ok.

DirectionalSuburban

zGenerally, select low or medium gains and preset electrical tilt

angle.

DirectionalUrban

ReferenceReferenceTypeTypeLandformLandform


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Contents


1.1 Basics

1.2 Antenna system


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Electric Downtilt Antenna

z In Electric Downtilt Antenna, feeding network is used to adjustamplitude& phase of input signal from different path, so as to

form radiation beam with a certain shape.


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Classification

zz FETFET(Fixed Electric Downtilt)

Electric Downtilt is fixed

zz METMET(Mechanical Electric Downtilt)

Electric Downtilt is changed by knob orpulling bar

zz RETRET(Remote Electric Downtilt)

Electric Downtilt is changed by OMC.

Add RCU (Remote Control Unit) to MET.


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Control cableControl cable(DC+ control signals )(DC+ control signals )

Pulling barPulling bar

MET and RET

METMET

RadomeRadome

Pulling barPulling bar

RadomeRadome

RCURCU

RETRET


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Contents


1.1 Basics

1.2 RET Antenna system


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RET Antenna System

BTSBTS

RCURCUSBTSBT

AntennaAntenna

OMCOMC

BSCBSC

BTBT

BTSBTS

RCURCUSBTSBT

AntennaAntenna

BTBT


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Component

z

RCU (Remote Control Unit) motor driving and controlling unit for antenna.

Receive and execute command from BTS, drive the motor which

drives the adjustable phase shifter, so as to change the downtilt.

z SBT(Smart Bias-Tee)

Abstract DC (power source) and controlling command from feeder.

Provide DC and controlling command for RCU.

z BT(Bias-Tee) Couple DC and controlling command into feeder.


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RCU

MotorMotor

Port 2 toPort 2 to

cascading RCUcascading RCUPort 1 toPort 1 to

SBTSBT

AntennaAntennaAntennaAntenna AntennaAntenna

BTSBTS

RCU

RCU

SBTSBT

RCU

RCU

Sector 1Sector 1

RCU

RCU

Sector 2Sector 2 Sector 3Sector 3

BTBT

z Port 2 is uesd when RCU is cascaded, where one SBT control several RCU.

z If several antenna use the same downtilt, RCU can be cascaded.


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BT

DC/OOKDC/OOK

RFRF

OOKOOK

DCDCRFRF

Port 1 to feeder/antennaPort 1 to feeder/antenna

Port 3 to DATU BoardPort 3 to DATU Board

RF signalRF signal DC signalDC signal OOK signalOOK signal

Port 2 to BTSPort 2 to BTS

Bias TeeBias Tee

z DATU board give the controlling command for Antenna.


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Course Name


N-59


SBT

Smart Bias TeeSmart Bias Tee

RFRFsignalsignal

DCDCsignalsignal

OOKOOKsignalsignal

Port 1 to AntennaPort 1 to AntennaPort 2 to FeederPort 2 to Feeder

Port 3 to RCUPort 3 to RCU

RS485RS485signalsignal


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Course Name


N-60


Summary

z In this course, we have learned:

Antenna working principles

Important Antenna specifications

Choose correct type of antenna in different situation

Electric Downtilt Antenna


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Course Name N-61

Thank youwww.huawei.com

omp110030 antenna basics issue1.01

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