Basic Knowledge of Antenna and Antenna Selection _2

7/29/2019 Basic Knowledge of Antenna and Antenna Selection _2

http://slidepdf.com/reader/full/basic-knowledge-of-antenna-and-antenna-selection-2 1/60

Basic Knowledge of Antenna and AntennaSelection

Radio Network Planning & Optimization Department

Mobile Institution



Purpose

After learning this course you will be able to:

Know the concept of dipoles

Understand basic properties of antenna

Mater the principle of antenna selection



Index

Outline of antenna

Technical data

Types of antennas and their development trend

Principle of antenna selection



make optimize

project

Networkoptimization

Collect data

information

Deal optimize

project

Regulate and

verify

Antenna optimization

Optimize cover range

Average calling mission

Improve calling quality

Improve network running quality

The function of antenna Outline of antenna



Antenna is the conversion for circuit

signal of communication equipment toradio in the air like the bridge tower.

Antenna is the key equipment for thesending and receiving of radio.

The gain, covering direction, beam,

available driver power, configuration and

polarization function will affect the

communication.

Outline of antennaThe outline and function of antenna



Wavelength

1/2 Wavelength 1/4 Wavelength

1/4 Wavelength

1/2 Wavelength

Dipole

1800MHz 166mm

900MHz 333mm

Dipole Outline of antenna



One dipoleReceive power

1mw

n dipolesReceive power

4mw

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




10log(8mW/1mW) = 9dBd

Sector antennaReceive power : 8mW

Omnidirectional arrayReceive power :4mW

(top view)

Antenna




Index

Outline of antenna

Technical data





GSM 900

DCS 1800

GSM900+DCS1800

CDMA

Technical dataElectrical properties--frequency



BANDWIDTH = 960 - 890 = 70MHz

Optimum 1/2 wavelengthfor dipole at 925MHz

at960MHz

AntennaDipole

at890MHz

Electrical properties--frequency Technical data



50

Cable

50 ohms

Antenna

50 ohms

Electrical properties—input impedance Technical data



9.5 W

50 ohms

forward: 10W

backward: 0.5W

Return Loss 10log(10/0.5) = 13dB

VSWR (Voltage Standing Wave Ratio)

Electrical properties—

voltage standing wave ratioTechnical data




voltage standing wave ratioTechnical data



Vertical Horizontal

+ 45degree slant - 45degree slant


polarize modeTechnical data



V/H (Vertical/Horizontal) Slant (+/- 45 )





Linear,vertica

dual linear 45 slant





Electrical properties—gain Technical data



dipole

idea point fountain zerowaste equality radiation

eg: 0dBd = 2.15dBi

dBd and dBi

2.15dB




120 (eg)

Peak

Peak - 10dB

Peak - 10dB

10dB Beamwidth

60 (eg) Peak

Peak - 3dB

Peak - 3dB

3dB Beamwidth


wave widthTechnical data

El t i l ti




wave width Technical data

El t i l ti



Sector antenna 30 /65 /90 /105 /120

omni-antenna 360


wave width Technical data

El t i l ti





El t i l ti



horizontal 3dB beam width 3dB width choose graph



El t i l ti



No declination

Machine declination

Fixed electrical

declination

Measurable electrical

declination

Remote control

declination

Machine electrical

combine use


declinationTechnical data

El t i l ti





El t i l ti





Electrical properties



No declination Electrical declination Machine declination






The max value of main petal to

the max value of back petal ratio

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

Back power Front power


Front to Back Ratio Technical data





petal restrain & zero point fillTechnical data




Down assistant petal

(dB)

Up assistant petal (dB)


petal restrain & zero point fillTechnical data




Continuous :25-1500watts

peak :n2 p


power capability Technical data




1000mW ( 1W) 1mW

10log(1000mW/1mW) = 30dB

For multi-port antenna using, the isolation degree

between every port must be bigger then 30dB


isolateTechnical data




The same frequency, different frequency,

dual-frequency antenna port>30dB


isolate Technical data



Length width high

length relate with vertical petal, gain

width relate with horizontal petal

high relate with the technology

of antenna

Mechanism properties parameter Technical data

Mechanism properties parameter—



PVC, ABS, fiberglass etc.

Prevent from bask, freeze, salt fog, burning

and aging.

Mechanism properties parameter

material Technical data




good look, environment protection


appearance color Technical data




type value

-40 C—+70 C


working degreeTechnical data




For example:

83N at 160 km/h


wind carry Technical data




The smaller

the better


windward Technical data




7/16”DIN

N

SMA

female


tie-in Technical data




Mast diameter 45-90mm


hold pole Technical data

Mechanism properties parameter—T h i l d




thunder resistantTechnical data



index

Outline of antenna

Technical data



T & d lki d f BTS t



According to

frequency

GSM900、GSM1800、

GSM900/1800 dual-frequency

According to

polarization

Vertical，45liner polarize，level，

circularity polarize

According to

direction chartOmni-antenna，sector antenna

According to

declination mode

no，mechanism，fixed electrical，

measurable electrical， remote control

According to

functionsend，receive，send-receive together

Types & developmentkinds of BTS antenna

d l t d T & d l t



develop trend

Width

frequency

band

Multi-

function

High

integrated

Types & development

d l t d T & d l t



GSM900/1800 dual-frequency

and dual-polarize

Remote control isolate

electrical declination antenna

develop trend Types & development

d l t d T & d l t



C 900/1800 C 900/1800

+45 / 900 +45 / 1800 -45 / 900 -45 / 1800

+45 / 900 -45 / 900

+45 / 1800 -45 / 1800

develop trend Types & development



index

Outline of antenna

Technical data



i i l f t l tiRadio environment for



principle of antenna selectionsuburb/country

antenna choose forprinciple of antenna selection



Polarize modAs it is hard to choose BTS address and space for antenna, the dual-

polarize antenna need to be chose

direction chatAccording duplicate using of frequency, sector antenna need to

be chose

3dB Power

Beam width

For controlling the cover range to restrain disturb, the horizontal

plane 3dB power beam width of antenna in urban should be 60~65°

antenna gain

The gain of antenna, which should be used in urban, is 15-16dBi.

The antenna with lower gain could be used to cover the blind urban

area.

Declination

degree

Down tilt antenna is suggested, and electrical declination antenna

in sometimes.

Characteristics of application environment:

When The distribution of BTS is dense, the cover range of single BTS need to be small,

the over cover phenomena and the disturb between BTS need to be decreased, the

duplicate using of frequency need to be increased.

urbanprinciple of antenna selection

Radio environment forprinciple of antenna selection



urbanprinciple of antenna selection





Environment around should be considered in Sparse distributing, low traffic, larger

coverage situation.

Polarize mod Choose vertical polarize or dual-polarize antenna

direction

chat

The sector antenna with 90°or 105°horizontal plane 3dB power beam

width is used.

3dB Power

Beam width

The omni-antenna with 90°or 105°horizontal plane 3dB power beam

width or wider is used.

antenna gain The antenna with high gain is suggested, which is 16-18dBi for

sector antenna or 9－11dBi for omni-antenna in rural and suburb area.

Declination

degree

Mechanism declination is suggested. The zero fill antenna is needed

when the high level of antenna is greater then 50 meters to avoid

dark under antenna phenomenon.

suburb/countryprinciple of antenna selection




highway

principle of antenna selection





Low traffic, high speed moving The covering problem is the key issue. For strap covering, dual-cell coverage is

needed. Sometimes, the omni-cell is used in some spots.

Polarize mod Choose vertical polarize or dual-polarize antenna according to

particular situation

direction

chat

To cover railway and road, the narrow beam width and high gain

antenna should be used.

3dB Power

Beam width

The gain of sector antenna is higher, the horizontal plane 3dB power

beam width is about 30°

antenna gain The gain of sector antenna should be 18dBi－22dBi, and omni-antenna

is 11dBi

Declination

degree

Down tilt is not needed for highway covering, and the mechanism

declination antenna is suggested.

highwayprinciple of antenna selection




Figure 6.5 beauty spot

mountainous areaprinciple of antenna selection





in the knap out of the way, serious mountain block, big radio pass loss，hard to cover area.

Polarize modChoose vertical polarize or dual-polarize antenna according to

particular situation

direction chat Choose omni-antenna or sector antenna

3dB Power

Beam width

For BTS built on the mountain, if the level of cover area is

low, the antenna with bigger 3dB power beam width need to be

chose

antenna gainChoose middle antenna gain according to the distance of cover

area, omni-antenna(9-11dBi), sector antenna(15-18dBi)

Declination degree

If BTS be built on the mountain, when the cover area is under

the mountain, the antenna with zero point filling or

declination need to be chose

mountainous areaprinciple of antenna selection

Basic Knowledge of Antenna and Antenna Selection _2

Documents

Transcript of Basic Knowledge of Antenna and Antenna Selection _2