wpo-05 wcdma antenna model selection

7/27/2019 WPO-05 WCDMA Antenna Model Selection

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WCDMA Antenna Model Selection

ZTE University



Content

Antenna Principles and Parameters

Antenna Application and Model Selection



Electric fieldElectric

field

Electric

field

Di p ol e

Transmitting direction of radio wave

Magnetic

field

Magne

tic field

Basic Knowledge of Radio Wave

Transmission of radio wave




Relation of wavelength, power and transmittingspeed of radio wave：

It can be indicated by formula λ＝Ｖ/ｆ. In the formula,

V is speed, with unit of m/s;ｆis frequency, with unit of

Hz; λ is wavelength, with unit of m. It can be easilyfound from the formula that, speed of the same-

frequency radio wave is different while transmitting in

different medias, thus its wavelengths are also different.

Wavelength




Polarization of radio wave When radio wave is transmitting in space, the direction

of its electric field changes with according to certain

rules, and this is called the polarization of radio wave.



Antenna Principles

What is antenna？

Transmit the electric signal from wire to space as radio wave…...

Receive radio wave and generate electric signal

One of the key components in radio communication system,

performance of the antenna directly affects the operation of the

whole communication system

Blah blahblah bl ah



Antenna Principles

When AC is carried on the wire, radiation of electromagnetic wave can be formed, and it is closelyrelated to the length and shape of the wire. When thelength of wire increases and reaches to wavelength,electric current on the wire also incredibly increases, thus

strong radiation will be generated. Usually, straight wirethat can generate obvious radiation is called dipole.

Relations between angle of the dipole and electromagneticradiation



Wavelength

1/2 Wavelength

1/4 Wavelength

1/4 Wavelength

1/2 Wavelength

Dipole

Antenna electrical parameters- 1/2

wavelength dipole Symmetrical dipole is a classic, and the most widely used antenna till

now. A single symmetrical 1/2 wavelength dipole can be easily andindependently used or used as a parabolic antenna feed, and multiplesymmetrical 1/2 wavelength dipoles can also be used to form aantenna array.

A dipole with the two rods of the same length is called symmetrical

dipole. With the length of the rod 1/4 wavelength, and the full lengthbeing 1/2 wavelength dipole, it is called 1/2 wavelength symmetricaldipole



In 850MHz 1/2 wavelengthdipole is the best

In

890MHz

Antenna

dipole

In

820MHz

Antenna Electrical Parameters-Operational

frequency band

Antenna is always working in a certain frequencyrange.

Considering the reduction of out-band interference

signal, bandwidth of the selected antenna should

be just meeting the band requirement.



Antenna Electrical Parameters – Gain of

Antenna

The definition of the gain of an antenna is related to the 1/2

wavelength dipole or the omni radiator. The omni radiator assumes

that the radiation powers in all directions are equal. The gain of the

antenna in a certain direction is a value of the field strength generated

in this direction over the intensity by the omni radiator in this direction.

Gain of antenna is an Important parameter indicator for antenna model

selection

The selection of antenna gain is related to the size of the coverage

2.15dB

Gain through the comparison of a

antenna and symmetrical dipole is

referred as “dBd”

Gain through the comparison of a

antenna and each radiator with

same direction is referred as “dBi”

For example: 3dBd = 5.15dBi



E.g.：1 symmetrical dipolereceiving power ：1mW

4 symmetrical dipole arrayreceiving power ：4 mW

GAIN= 10log(4mW/1mW) = 6dBd


Antenna

The high gain of plate antenna is combinedthrough antenna array by multiple basic dipoles




Antenna Radiation energy can be controlled and focused to one direction

through the reflecting plate Place the reflecting surface on one side of the array to form sector-

coverage antenna

In our “sector -coverage antenna”, reflecting side focused power to one

direction and further increased the antenna gain

Here, compared with single symmetrical dipole, the gain of “sector -

coverage antenna is 10log(8mW/1mW) = 9dBd

“Omni array”

E.g. 4mW in receiver

“sector-coverage antenna”

will be 8mW in receiver

Upward view

Antenna



Example of Antenna Gain

EIRP

(Effective radiation power) example

BaseStation

Transmitter

(20 watts)

Convert to dBm

10Log(20) + 30 = +43 dBm

jumper

Heliax

Cable

jumper

-0.5dB

-0.5dB

-3dB

Antenna Gain

= + 18 dBi

Ant Input

Power = + 39dBm

EiRP = +39 + 18 = +57 dBm



dB dBm dBi dBuv

dB：

it is only a relative value, dB＝

10log (P1/P2). For example, transmission power of base station A is 600mw,and B is 300mw, so transmission power of base station Ais 10lg (600/300)＝3 dB higher than that of station B. Fromthe formula we can see that, dB refers to the comparative

value of two powers, and it has no unit. dB is value with nounit.

dBm：it is a value used to compare the absolute power value, whose formula is dBm=10lg (power/1mW). For example, the commonly used base station is 500mw,

which is also10lg(500mW/1mW)＝27dBm (means 27dBmw) after converted to dBm. Another unit dBW is tochange 1mW to 1W in the formula, while others remain thesame.1W=30dbm;1mw=0dbm，1W＝0dbW



dB dBm dBi dBuv

dBi：as explained before, it refers to a relative value. dBi is thedefinition of the antenna gain, but not a unit, and I is the abbreviation of

isotropic Actually it is dB.

dBuV：same definition as dBm. It is right the field strength unit we see

from field strength analyzer and mobile testing mode. Its relation with

dBm is: dBm：10lg(power/1mW)。

dBuV: 20lg(voltage/1uV), power ＝squared voltage/50 ohms (the same

for common systems when port impedance is 50 ohms)

Therefore：dBuv = dBm + 107 dB



Difference between dBd and dBi

A single symmetrical

dipole has donut-shaped

pattern of radiation

A isotropic radiator has

the same radiation at all

the directions

The gain of the antenna

compared with the 1/2

wavelength dipole is

indicated with dBd. The gain

of the antenna compared

with the isotropic radiator is

indicated with “dBi”.

E.g.: 3dBd = 5.15dBi

2.15dB

Gain of symmetrical dipole is 2.15dB



Antenna Electrical Parameters-Direction f

Antenna

Direction of antenna refers to the capability thatantenna radiates electromagnetic wave to a

certain direction. For receiving antenna, direction

means the receiving capability antenna to electric

waves that from different directions. Characteristiccurve for direction of antenna is usually illustrated

by direction diagrams.

Direction diagram can be used to indicate the

capability antenna transmit and receive

electromagnetic wave at all directions in the space.



Antenna Electrical Parameters-Direction f

Antenna



Antenna Electrical Parameters-Direction f Antenna

60°

(eg)Peak

- 3dB点

- 3dB点

3dB beamwidth

Directional antenna

Omni antenna Cell

coverage

Neighbor cell

interference

Gain of antenna

Horizontal lobe angle



Antenna Electrical Parameters-Vertical lobe

angle

15°

(eg)Peak

Peak - 3dB

Peak - 3dB

Narrower vertical lobe angle will cause more blind coverage areas;

For specific coverage target, larger vertical lobe angle should be used

Directional antenna

Omni antenna



Antenna Electrical Parameters-Beamwidth



Antenna Electrical Parameters - Lobe width

On the direction diagram of horizontal (vertical) antenna, anglebetween the two points where the gain reduces 3dB compared to thatof the power at maximum point of the main lobe can be defined as thehorizontal (vertical ) lobe width. (3dB width, can be other definitions).

Most of the antenna radiation energy is gathered in lobe width, and thesize of lobe width indicates the concentration of antenna radiation.

The horizontal lobe width of an Omni antenna is all 360, while for directional antenna, it can be 20, 30, 65, 90, 105, 120, 180 etc,and 65, 90 are usually used.

The vertical lobe width of antenna is usually 3～80, and antennas of 5～18 are mostly used by base stations.

Gain of antenna is closely related to horizontal and vertical lobe width.Generally, the smaller the lobe width, the bigger the gain. When wedefine these three factors, all of them need to be considered.



Antenna Electrical Parameters - Lobe width

For different transmitting environment and topography, the selection of

the horizontal and vertical lobe width of antenna can generally follow

the principles below:

Horizontal lobe width

For areas with large number of base stations, small coverage

radius and wide traffic distributions, horizontal lobe width should besmaller.

For areas with big coverage radius and little traffic distributions,

horizontal lobe width should be larger.

Vertical lobe width

For areas with plain topography, sparse buildings and low averageheight, vertical lobe width should be smaller.

For areas with complex topography and big gap, vertical lobe width

can be larger.



Antenna Electrical Parameters-Antenna

Diversity

Space diversity Space diversity：When there is certain distance between the two

receiving antennas, the same signal with different fading will bereceived. If the correlation coefficient of these two signals is lessthan 0.7, the requirement of diversity reception will be satisfied.The requirement of space diversity to antenna installation are:

D>10λ h/D≤11 h is the antenna height, while D is the antenna distance.

Space diversity antenna only support distance on horizontaldirections.

Polarized diversity Polarized diversity: Each sector of each carrier frequency uses a

45°dual-polarization antenna to complete diversity reception.

The two vertical 45°polarizations are orthogonal polarization, whichhas better diversity reception capability.



Antenna Electrical Parameters-Polarization

Mode The polarization direction of the antenna refers to the direction of the electric field

intension in antenna radiation. Base station antenna usually uses linear polarization.With ground as the benchmark, it is vertical polarization (VP) when electric field vector is

vertical to the ground, and horizontal polarization when it is horizontal (HP). For dual-

polarization antenna, +45°and -45°orthogonal dual-polarizations are commonly used.

VP HP + 45 polarization - 45 polarization

V/H tilted (+/- 45°)

Using dual-polarization

antenna in urban areas can

greatly reduce antenna

numbers, simplify antenna

installation, lower cost, and

save antenna spaces.




Mode Dual-polarization antenna is assembled by combining two antennae with

orthogonal polarization packed in the same antenna cover , the number of theantennae installed will be greatly reduced if apply dual-polarization antenna,

which will result in the simplification of the antenna installation process, the

reduction of the cost and the saving of the space for antenna installation. For

dual-polarization antenna, +45°and -45°orthogonal dual-polarizations are

commonly used.

V/H Tilted (+/- 45°)




Mode

For urban areas, there is a large number of base station,and each base station with a small coverage radius.Considering the simple installation, and base stations inurban area has a big adjustment probability, dual-polarization antenna is recommended to ensure the

diversity efficiency. As to suburban and rural areas, there is a small number of

base station, and each station with a large coverage radius.Reception will be improved if space diversity is applied.Here the single-polarization antenna of space diversity can

be used. Generally, if there is no specific requirement, the complete

use of dual-polarization antenna is recommended, as it isgood for implementation and the future adjustment.



Antenna Electrical Parameters-Front-to-back

suppression ratio

In antenna direction diagram, comparison of themaximum electrical level for front and back lobe is

called the front-to-back ratio.

Front power Back

power

To avoid interference to the neighbor cell from the back lobe, it is

better for WCDMA system to choose antennas with larger front-to-

back ratio. The front-to-back ratio of outdoor antenna should better

be larger than 25dB.



Antenna Electrical Parameters-downtilt mode

Antenna downtilt is divided into mechanical downtilt and electrical

downtilt, and electrical downtilt can be further divided into fixed

electrical downtilt and adjustable electrical downtilt.

Mechanical downtilt antenna is to decline antennas while

constructing, which is cheaper and mainly used in the environment

when downtilt angle is less than 10.

Electrical downtilt antenna is relatively expensive, who has a larger

downtilt scope (can be bigger than 10). There is no obvious

change for the antenna direction diagram when downtilt angle is

large, and the back lobe declines at the same time.

For circumstances of large downtilt angle requirement, small-angle

fixed electrical downtilt and mechanical downtilt are commonly

used.




When the antenna downtilt angle is larger than 10 degree, the antenna

direction diagram will be seriously changed, and it is suitable to choose

antennas with electrical downtilt.

No downtilt Electricaldowntilt

Mechanicaldowntilt

Urban area antennas are generally using (fixed)

electrical downtilt + mechanical downtilt




The main purpose of downtilt is to decline the main beam, so as to

reduce the radiation level to the neighbor areas. This way, the carrier

wave level is reduce at the edge of the area, but interference level is

reduced much more than the carrier wave level.

No downtilt Electrical

downtilt

Mechanical

downtilt



No downtilt Electrical downtilt




No downtilt Mechanical downtilt




10°electrical

downtilt

10°mechanical

downtilt

6° electrical

downtilt

+ 4° mechanical

downtilt




A t El t i l P t F t t b k



F/B = 10 log(front power/back power） typically： 25dB

Back power Front power

Antenna Electrical Parameters-Front-to-back

ratio

The comparison of maximum front and back lobevalue

A t El t i l P t I t



Antenna Electrical Parameters- Input

impedance

The ratio of signal current at the input end of antenna and

the signal current is called impedance of antenna. Input

impedance is divided to resistance and reactance. The

reactance of input impedance will reduce the effective

signal power that entered from antenna to feeder.

Therefore, reactance should be zero to make inputimpedance of the antenna become pure resistance.

For any antenna, make adjustment through the antenna

impedance. Within the required work frequency range, the

real part of impedance is very small and imaginary part isvery close to 50 , so that the antenna impedance is Zin =

Rin = 50 . This is necessary to ensure the impedance of

antenna and that of feeder to be well matched.



Antenna Electrical Parameters-VSWR

VSWR: Voltage Standing Wave Ratio

When feeder matches antenna, high frequency energy is

completely absorbed by loading, and there is only incident wave

but no reflection wave on the feeder. However, when feeder does

not match antenna, that is when antenna impedance not equal with

specific feeder impedance, loading cannot completely absorb the

high frequency energy transmitting on feeder, but just part of them.Part of incident wave was reflected to form reflection wave. The

bigger the VSWR, the bigger the reflection, and the worse the

match.

9.5 W80

ohms50 ohms

front: 10W

back: 0.5W




Antenna VSWR is the index indicating how much theantenna feeder is matched with BS (transceiver). Thegeneration of VSWR: because the incident wave power istransmitted to the antenna input end and is not completelyabsorbed (radiation). Reflection wave is generated andstacked to generate VSWR. Assume the transmissionpower of a BS is10W, and 0.5W is reflected, thus loss of the reflection wave can be calculated: RL＝10lg(10/0.5)=13dB, and the reflection coefficient: RL=-20lg, ＝0.2238

VSWR=(1+)/(1- )＝1.57 Generally, VSWR is required to be less than 1.5. VSWR is

the less the better, but it is unnecessary to expect for asmall VSWR while engineering.



VSWR

Loss of

reflectionwave(dB)

Transmissionloss(dB)

Reflectionpower (%)

TransmissionPower (%)

1.00

1.10

1.20

1.30

1.40

1.50

2.00

26.4

20.8

17.7

15.6

14.0

9.5

0.00

0.01

0.04

0.08

0.12

0.18

0.51

0.0

0.2

0.8

1.7

2.8

4.0

11.1

100.0

99.8

99.2

98.3

97.2

96.0

88.9

VSWR is required to be less than 1.5


A t El t i l P t Sid l b



Down side lobe (dB)

Up side lobe (dB)

Antenna Electrical Parameters-Side lobe

suppression and fill-in






Antenna Electrical Parameters Side lobe




suppression and fill-in Side lobe on the main antenna lobe not only wastes the energy of antenna

radiation, but also forms interference to the neighbor cells, thus the side lobeshould be suppressed, especially the first big side lobe.

Side lobe under the main antenna lobe need to enable effective coverage toareas around, thus the zero point should be filled in.

Electrical level of the first side lobe on main lobe should be less than18dB

Electrical level of the first zero point under the main lobe should be larger than

20dB

- 4 0

- 3 5

- 3 0

- 2 5

- 2 0

- 1 5

- 1 0

- 5

0

3 1 0 3 2 0 3 3 0 3 40 3 5 0 0 1 0 2 0 3 0 4 0

First upward side

lobe

First zero point

Antenna Electrical Parameters Cluster



Antenna Electrical Parameters - Cluster

antenna, Multi-frequency antenna

Cluster antenna Multi-frequency

antenna

Antenna Electrical Parameters Cluster



Antenna Electrical Parameters - Cluster

antenna, Multi-frequency antenna During the implementation of

3G, the finding of new basestation will be harder than thatin 2G, and the rate is alsoincreasing

Due to the improvedconsciousness of environment

protection, citizens andcommunities more and moredislike so many antennas beingbuilt around them.

Demand of station sharing andantenna feeder sharing will belargely raised in 3G planning.

Multiple-frequency antennasupports radio sending andreceiving on at least twofrequency bands.

board

High frequency stream

Low frequency

stream

Input interface

Decline

adjustment(independent

adjustment)

Antenna Electrical Parameters Connector



7/16‖DIN

N

SMA

Advantage of DIN connector:

Improve the intermodulation products, can

stand 4 times more power than N type

connector, has consistent and the best

VSWR performance.

Antenna Electrical Parameters-Connector

Type

Antenna Electrical Parameters Antenna



Antenna Electrical Parameters-Antenna

holding pole



Content

Antenna Principles and ParametersAntenna Application and Model Selection



Antenna Model Selection

During antenna selection, many parameters willbe involved, among which:

Parameters such as radiation direction diagram, gain,

horizontal lobe width, vertical lobe width, downtilt, etc.

need to be selected in accordance with the topography,physical objects, base station height, and coverage

radius in the area;

Selection for other parameters are relatively simple, and

will be determined according the system design.



BS Antenna Feeder System

8 Lightning protector

Main feeder （7/8“）

5 Feeder

nail6 chute

4 Grounding equipment

3 Joint seals

Sealed insulating tape, PVC

insulating tape

1 Antenna adjustment mount

GSM/CDMA

Plate antenna

Holder （50~114mm）

2 Outdoor feeder

9 Indoor super-soft feeder

7 Feeder line

window

BS main equipment




Antenna adjustment mount Use for the adjustment of antenna tilting angle, which is generally：

0°～15 °；

Outdoor jumper cable Use for the connection between antenna and the 7/8〞main feeder.

The frequently used jumper is of 1/2〞feeder, with a length of 3 M.

Joint seals Used for the connector sealing at two ends of outdoor jumper cable

(connected with antenna and the main feeder). Materials thatfrequently used are insulted waterproof tape (3M2228) and PVCinsulating tape (3M33+).

Grounding equipment (7/8〞Feeder grounding component) Mainly used for lightning protection and discharge, which is directly

connected with the outer conductor of main feeder while installation.Generally, there are three units for each feeder, and locatedrespectively on the top, middle and bottom position of the feeder.

Direction for the grounding point must be the same as current.




7/8〞Feeder nail Used to fix the main feeder, with 1 for every 1.5 m on vertical direction and

every 1 m on horizontal direction. (For indoor main feeder, feeder nail isnot essential, but usually bundled and fixed with white nylon cable ties.)

Two types of 7/8〞feeder nails are generally used: double connection andtriple connection.

7/8〞double connection nail can fix two feeders, while triple connectionone can fix three feeders.

Chute Used for distribution & placement of main feeder, transmission line, power

line, and the installation of feeder nail.

Feeder window Mainly used to pass through all kinds of cables, and prevent the entering

of rain, birds, mouse and dust.

Lightning protector(Lightning arrester) Mainly used for lightning protection and discharge. It is installed between

the main feeder and indoor super-soft jumper cables. Passing through off-line window, its grounding cable is leaded outdoor and connected with thetower body or directly connected with the grounding network.




Indoor super-soft jumper cable

Use for connection between main feeder (via lightning arrester) and BSmain equipment. The frequently used jumper cable is of 1/2〞super-softfeeder, with a length of about 2~3m. Due to the different interface andinterface directions of BS equipment from various manufactures, theconnectors of indoor super-soft jumper cables for main equipment are alsodifferent. The frequently used connectors are of 7/16DIN model and N

model, with both straight and tilted ones. There are two main functions for black nylon bundling tie:

（1）Temporarily bundle and fix the main feeder during installation. It canthen be cut and removed when feeding nails are installed.

（2） At the turning point of main feeder, it is inconvenient to use feeder nails, thus nylon bundling tie will be used for the fixing. Black nylon

bundling tie is also used for the fixing of outdoor jumper cables. White nylon bundling tie: Used for the bundling and fixing and of the

indoor main feeder part and indoor super-soft jumper cables.




According to the type of BS coverage, it is dividedinto:

（1） High-density urban areas

（2） Cities and towns

（3） Suburban areas （4） Railway, express way, and countryside

Antenna Working Frequency Band and




Polarization

The selection of antenna working band mustsubject to the designed system frequency band.

Considering the reduction of out-band interference

signal, bandwidth of the selected antenna should

just meet the frequency band requirement. BS antenna usually applies polarization. Single-

polarization antenna uses vertical polarization,

while dual-polarization antenna uses 45 dual

polarization.





Polarization For urban area, there is a large

number of BS, and coverage radiusof each BS is relatively small.Considering the convenientinstallation and big probability of BSadjustment in urban areas, dual-

polarization antenna isrecommended.

As to suburban and rural areas,there is a small number of base

station, and each station with a largecoverage radius. Reception will beimproved if space diversity is applied.Here the single-polarization antennaof space diversity can be used.



Direction Diagram of Antenna Radiation

BS antenna can be divided into

Omni antenna and directionalantenna according to the

radiation direction diagram.

Omni antenna has the same

radiation strength in the

same horizontal plane. It issuitable for coverage of the

whole cell.

Directional antenna has

directional radiation in the

same horizontal plane, andradiation energy is relatively

concentrated. It is suitable

for coverage of sector cells.



Antenna Lobe Width and Gain

On the direction diagram of horizontal (vertical) antenna, angle

between the two points where the gain reduces 3dB compared to thatof the power at maximum point of the main lobe can be defined as thehorizontal (vertical ) lobe width. (3dB width, can be other definitions).Most of the antenna radiation energy is gathered in lobe width, and thesize of lobe width indicates the concentration of antenna radiation.

The horizontal lobe width of an Omni antenna is all 360, while for directional antenna, it can be 20, 30, 65, 90, 105, 120, 180 , etc

The vertical lobe width of antenna is usually 3～80, and antennas of 5～18 are mostly used by base stations.

Gain of antenna is closely related to horizontal and vertical lobe width.Generally, the smaller the lobe width, the bigger the gain. When we

define these three factors, all of them need to be considered.

Horizontal Lobe Width Vertical Lobe Width



Horizontal Lobe Width, Vertical Lobe Width

and Gain

For different transmitting environment and topography, the

selection of the horizontal and vertical lobe width of antenna cangenerally follow the principles below:

Horizontal lobe width：For areas with large number of base

stations, small coverage radius and wide traffic distributions,

horizontal lobe width should be smaller; For areas with bigcoverage radius and little traffic distributions, horizontal lobe

width should be larger.

Vertical lobe width：For areas with plain topography, sparse

buildings and low average height, vertical lobe width should

be smaller. For areas with complex topography big gap,vertical lobe width can be larger.




Following are suggestions to thee differentsituations:

Urban area

S111 BS in urban area usually selects antennas with

horizontal lobe width of 65, vertical lobe width of 7～10, and gain of the antenna is 15～18dBi. For S110 or

directional single-sector station, antennas with

horizontal of 65, 90 or even more can be selected

according to the actual condition; selection of verticallobe and gain of the antenna is the same as that of

S111 station. As to Omni station, antennas with

relatively small gain and electrical downtilt should be

selected.




Suburb and townships For these areas, traffic is not

large, and big coverage is the

main concern; BS distance is

quite long; we can select the65°directional antennas (triple-

sector) with single polarization,

space diversity and higher

gain (17dB) or 17dB

90°directional antennas

(double sector, as shown

below).

A M d l S l i




Suburban and rural areas We can select directional antennas with horizontal lobe

width of 90, vertical lobe width of 5～7, and the gain

is of 15～18dBi. And also, we can select Omni

antennas with vertical lobe width of 5～7, and the gain

is of 9～12dBi.

A t M d l S l ti




Water surface (large lake, sea, etc.), Gobi, anddesert

Directional antenna: If the target coverage area is

relatively broad, we can consider to use antennas with

horizontal lobe width of 90 or 105, vertical lobe width

of 5～7, and the gain is of 14～18dBi; For areas with

long coverage distance but small width (long and

narrow lake, topographical effects, etc.), we can

consider to use narrow-beam antennas of 65, etc..

Omni antenna: Antennas with vertical lobe width of 5～7 and gain of 9～12dBi will be selected.

A t M d l S l ti




Roads, railway and other panhandles

Antenna model selection for roads and railways should

be determined in accordance with the distance and

shape of roads and railways.

For straight route, we can select to use high-gainantennas with horizontal lobe width of 20～30, vertical

lobe width of 5～7.

For big-bending route, we can consider the specific

condition and select to use antennas with horizontal

lobe width of 65, 90 or even more, and the vertical

lobe width can be 5～7.

A t M d l S l ti




A t M d l S l ti




Antenna for railway and towns: For small-traffic area that covers

railway, road, and towns, configuration for Omni station will be used.Weak directional antenna with 210°13dBi will be selected for the

requirement of coverage for railway, road and the roadside townships.

The direction diagram is：

A t M d l S l ti




Area with complex terrain and large gap

In the actual practice of network planning, we do

encounter the large-gaped areas. There are two kinds

of situations. When antenna should be higher than the

coverage area, antennas with vertical lobe width of

10～18 can be selected if necessary; when large part

of the coverage area is higher than the antenna height,

then antennas with large vertical lobe width of 18～30

can be selected.

A t d tilt



Antenna downtilt

In the city with dense BSs, the BSs may easily interfere with each

other. To ensure most power to radiate in the coverage area, anddecrease the interference on adjacent cells, while setting the initialdeclination angle of antenna, the half power point on the major plan of the antenna should point to the edge of coverage area. is the initialdeclination angle of the antenna; H indicates the valid height of BS; Lindicates the edge distance needed to be covered from the antenna of

the BS to the sector ; indicates the vertical lobe width of the antenna,and e indicates the declination angle of the antenna.

= arctg(H/L) + /2 – e

α

β/2

α+γe

L

H

A t d tilt



Antenna downtilt

In the suburb, countryside, country road, and sea surface etc.,

to make the coverage as wide as possible, decrease the initialdeclination angle, point the max. gain point of main lobe to the

edge of coverage area. The formula of declination angle is

follows:

α

β/2

α+γe

L

H

= arctg(H/L) – e

A t D tilt M d



Antenna Downtilt Mode

Antenna downtilt is divided into mechanical downtilt and

electrical downtilt, and electrical downtilt can be further dividedinto fixed electrical downtilt and adjustable electrical downtilt.

Mechanical downtilt antenna is to decline antennas while

constructing, which is cheaper and mainly used in the

environment when downtilt angle is less than 10. Electrical downtilt antenna is relatively expensive, who has a

larger downtilt scope (can be bigger than 10). There is no

obvious change for the antenna direction diagram when

downtilt angle is large, and the back lobe declines at the

same time. Small-angle fixed electrical downtilt and mechanical downtilt

are commonly used for their advantage on performance and

cost.





Following are the conditions that need to use electrical

downtilt: As to urban area stations with quite small coverage radius, a very

large declination angle is required to reduce interference toneighbor cells;

For urban area stations with large height, in order to reduce

interference to neighbor cells and the possibility of ―darkness under light‖, it is better to select first upward side lobe suppression andfulfillment at zero point, moreover, to use big-angle or adjustableelectrical downtilt antennas.

Compared with the relatively high stations around (E.g. station atthe top of the hill, or along the river), electrical downtilt antenna can

be chosen to control coverage.

As Omni station does not support mechanical downtilt, therefore,for a very high Omni station, electrical downtilt antenna should beselected according to different conditions.

Areas with Dense Traffic



Areas with Dense Traffic

The distance between the BSs is about 300 to 500

meters in the high-density areas with dense traffic,

and is about 10°～19°. Directional antenna with

9°inside electrical downtilt and +45°dual-

polarization, 1/2 power horizontal lobe width of 65° will be selected. Added with a mechanical

adjustable angle of 15°, there will be no change

for 1/2 power horizontal width on direction

diagram when main lobe declines10°～19°. It hasbeen proved to be able to meet the requirement of

dense-traffic area coverage with no interference.

Areas With Moderate Traffic



Areas With Moderate Traffic

The distance between the BSs is more than 500

meters, and is about 6°～16°. Directional

antenna with 6°inside electrical downtilt and

+45°dual-polarization, 1/2 power horizontal lobe

width of 65° will be selected, and there will be nochange for 1/2 power horizontal width on direction

diagram when main lobe declines 6°～16°. It is

able to meet the requirement of moderate-traffic

area coverage with no interference.

Areas with Relatively Sparse Traffic



Areas with Relatively Sparse Traffic

The distance between the BSs is much bigger,

and is about 3°～13°. Directional antenna with

3°inside electrical downtilt and +45°dual-

polarization, 1/2 power horizontal lobe width of

65° will be selected, and there will be no changefor 1/2 power horizontal width on direction

diagram when main lobe declines 3°～13°. It is

able to meet the requirement of sparse-traffic area

coverage with no interference.

Suggestions for Regular Antenna Model



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Selection

Area type Horizontal lobe angle Downtilt mode Gain

Dense urban

area

3-sector: 65o

directional antenna

Electrical downtilt +

mechanical downtilt

15~20dBi

Suburban

andtownship

3-sector: 65o or 90o

directional antenna

Mechanical downtilt 15~18dBi

Rural area 3-sector: 90o

directional antenna

Omni cell: Omni

antenna

Directional antenna:

mechanical downtilt

Omni antenna:

electrical downtilt

10~18dBi

Railway or

high way

2-sector: 33o

directional antenna

Mechanical downtilt 20dBi

Tunnel 8-mesh antenna, leakage cable

Antenna Selection Principle for Indoor



p

Distributed System

Following are the antenna selection principles for

indoor distributed system：

Not only meet the indoor coverage requirement, but

also reduce coverage for outdoor areas, and avoid

interference

Antenna should be beautiful, and its shape, color, size

should be harmonious with the indoor environment

Antennas for Indoor Distribution System—



y

Ceiling antenna Ceiling antenna is an Omni antenna,

which is installed at the ceiling of rooms, halls, and corridors. Thegain of ceiling antenna is generally2～5dBi, with horizontal lobe widthof 360, and vertical lobe width of around 65.

Ceiling antenna is of small gain andbeautiful outlook. When installed atceiling, the indoor field strength isaveragely distributed, which shouldbe first choice for indoor antennaselection. Ceiling antenna shouldbe installed as much as possible at

the middle ceiling in the room, butto avoid areas beside window or gate, where signals would be easilyleaked to outdoor areas.




Wall-mounted antenna

Wall-mounted antenna is a directional antenna,

which is installed on the wall of rooms, halls,

corridors, etc..

The gain of wall-mounted antenna is 6～10dBi,

with horizontal lobe width of 65, 45, etc., andvertical lobe width of around 70.

Mostly used in long and narrow indoor spaces.

While installing, there should be no blocking

object in front of them, and it should not directly

face windows or gates where signals would be

easily leaked to outdoor areas.

Antennas for Indoor Distribution System—8-



mesh antenna

8-mesh antenna is a

directional antenna withrelatively high gain, and

which is usually 9～14dBi.

Mainly used for the

coverage of elevators.

Antenna for Indoor Distribution System—



Leakage cable

Leakage cable can be considered as one kind of

antenna, which averagely send and receive

signals along its vertical direction through series of

open interfaces on outer conductor of the cable.

Leakage cable is suitable for environments liketunnel, subway, etc..




Other antennas

Some other indoor antennas include small-gain

spiral, rod-shaped antennas, and so on. There

gain are generally around 2, 3dBi; As these

antennas look not so good after installation, they

are seldom used.




Combiner

Combiner is used to combine base stations of two or more

different frequency bands. It is divided into double-frequencycombiner and triple-frequency combiner according to number of

the stations.

double-frequency

combiner

triple-frequency

combiner




Splitter

Reactive splitter is generally of coaxial design, power splitting

and output port properties are achieved through changes of impedance. As comon splitters, reactive splitters are divided into

2-splitter, 3-splitter, 4-splitter, and so on.

2-splitter 3-splitter




Bridge

3dB bridge is a combiner and splitter of same

frequency. The isolation between its input port and

output port are usually larger than 20dB.

In1 In2

Out2 Out1

Specific Antenna Model Selection—Beautified



antenna

AC-shaped installation

Respectively place one or two directional plate

antennas and BS into an imitative AC shell made

by special materials. Then fix it on the house roof,

eaves, or other places similar to conventionalcivilian AC installation.

Features：First choice for large-scope and flexible

installation.




antenna Antennas were hidden and

installed inside the ball of streetlights, while BSs in the basepoles, while makes theintegration of both BSs andantenna.

Features：Mainly used for high-

level and multi-floor residentialareas with convenientinstallation. Attention need tobe paid to the coordination withstreet lights inside the area, andbig contrast need to be avoided.This installation is relativelyexpensive. Moreover, for someresidential areas, cabling will becomplex.




antenna

Cactus-type

Fix BS to the green ground withbracket, and then cover the

whole BS using cactus with

antenna inside to achieve the

purpose of landscaping and

hidden installation. Features：For the real

landscaping and camouflage

installation, which are suitable

for villa groups and high-level,

multi-floor residential areas withlandscaping.




Installation place for the covered antenna series is relatively broad, and

coverage inside the cell is about 150m.

antenna 1、Plate antenna is placed

inside the glass cover, withbeautiful outlook and harmonywith environment, which ismainly placed against the wall indense urban area buildings.(Color of the cover can bedetermined by that of the wall) The gain of antenna: 12dBi Horizontal beam width：65°,90°

vertical beam width： 56°,34°.

Downtilt of the main lobe：-20°～ +20°.

Output port：8




antenna

A bucket-shaped antenna

is placed inside the lightball, and BS is in the fake

stone. With beautiful

outlook and harmony with

environments around,hidden communication,

decoration and lighting are

all achieved. This is mainly

used in residential areas

and at the roadside.




antenna


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Installing

position for

directional

plate antenna

Installing

position

for

directiona

l plate

antenna

antenna


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antenna


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After testing, plastic fake leaves have less effect to the antenna,

and performance of the antenna is not affected.

天线

antenna


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antenna


antenna



antenna

wpo-05 wcdma antenna model selection

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