GBO 006 E1 1 GSM Antenna System-63

7/27/2019 GBO 006 E1 1 GSM Antenna System-63

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Antenna System

ZTE University


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Objective

By the end of this course, you will be able: To Understand the concept of dipole

To state GSM antenna specifications

To comprehend the principle of antenna selection


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Blahblahblah bl ah

Radio Waves

A form of electromagnetic radiation typicallygenerated as disturbances sent out by

oscillating charges on a transmitting antenna


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Definition

An Antenna is an

device used to

collect or radiate

ElectromagneticWaves


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Linear antennas are

used:

Monopole (Slab)

Dipole Elements

Mobile Phones

Base Tranceiver

Station Antenna

Single Monopole

Patch Antenna

Array of dipoles

Antenna for mobile communication


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Antenna basic structure

Antenna are generallycomposed of stacked of dipole

bundling their radiated power

to form a desired antenna

pattern in vertical plainsaround the antenna

Depending on the gain desired

that wants to be achievedseveral of those diploes can

be arranged on top of one

another


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DIPOLES

Wavelength

1/2 Wavelength1/4 Wavelength

1/4 Wavelength

1/2 Wavelength

Dipole

1800MHz 166mm900MHz 333mm

Generation of radio waves


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1 dipoleReceived Power1mW

Multiple dipole matrix

Received Power4 mW

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

Half wave dipole


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Gain=10log(8mW/1mW) = 9dBi

Omnidirectional arrayReceived power1mW

(Overlook

Antenna

Sector antennaReceived power8mW

Isotropic antenna


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dBd and dBi


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BANDWIDTH = 960 - 890 = 70MHz

Optimum 1/2 wavelength

for dipole at 925MHz

at

960

MHz

Antenna

Dipole

at

890

MHz

GSM antenna frequency range


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Standard Value: 50

Cable

50 ohms

Antenna

50 ohms

Impedance


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VSWR1.5 = (VSWR-1)/(VSWR+1) RetureLoss = -20lg

Calculation of VSWR


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120(eg)

Peak

Peak - 10dB

Peak - 10dB

10dB Beamwidth

60 (eg) Peak

Peak - 3dB

Peak - 3dB

3dB Beamwidth

Bandwidth


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Directional Antenna65/90/105/120 Omni360

Omni-directional Directional

3dBm horizontal beamwidth


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3dBm vertical beamwidth


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Antenna structure types


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Vertical Horizontal

+ 45degree slant - 45degree slant

Polarization


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Space diversity


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

Polarization diversity


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Linear Polarization,verticalX Polarization, 45

Types of antenna


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Antenna down tilt

Mechanical down tilt

Fixed electronic down tilt

Adjustable electronic down tilt


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Input Signal

Electrical down tilt

Electrical downtilt can be fixed or adjustable

Fixed is tuned by the manufacturer

Adjustable allows adjustment in a certain level on the rear of the

antenna


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Non down tilt Electronic downtilt Mechanical

downtilt

Down tilt


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Antenna tilt development


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F/B = 10 log(FP/BP) typically 25dB

Back power Front power

FRONT-TO-BACK Ratio

Ratio of maximum mainlobe to maximumsidelobe


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Upper sidelobe suppression and null fill


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Upper sidelobe suppression and null fill


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913 MHz 936 MHz 959 MHz 982 MHz

IMD@243dBm

f1, f2, 2f1-f2, 2f2-f1

Intermodulation It occurs when two signals of a different frequency mix in a

non-linear device It can be a problem at any site that has two or more

transmitters

It can be caused by a transmitter of the same system or by a

transmitter in another site that is co-sited or has a site in theneighborhood


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1000mW ( 1W) 1mW

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

Isolation


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Antenna mechanical properties

Size Weight

Radome material

Appearance and color

Working temperature

Storage temperature

Windload

Connector types Package Size

Lightning Protection


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Dimension

LWH

Lengthconnected with vertical bandwidth and gain

Widthconnected with horizontal bandwidth

Heightconnected with techniques adopted


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PVC, Fiberglass Anti-temperature, water-proof anti-

agingweather resistant

Radome materials


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Good-looking Environment-protecting

Color


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Temperature range

Operation and storage

Typical range-40C +70C


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Connector type

7/16DINNSMA

Female/male


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Mast diameter 45-

90mm

Mast


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Direct Ground

Lightning protection


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Antenna types

By frequency band: GSM900, GSM1800,GSM900/1800

By polarization: Vertical, Horizontal, 45 linear

polarization, circle polarization

By pattern: Omni-directional, directional

By down-tilt: Non, mechanical, electronic

adjustment, remote control

By function: Transmission, receiver,transceiver


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7/8Main feeder

Feeder cable


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1/2JUMPER CABLE

Jumper cable


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7/16DIN-FDIN CONNECTOR7/16DIN-MDIN & N CONNECTOR

Connector


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Rf port 2

Grounding

Lightning arrestor


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Accessories

Trimming Tool or Hand Tool Kit Clamp

Earthing Kit

Wall Glands

Hoisting Stocking

Universal Ground Bar


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Antenna

7/16 Din Connector

7/8 Cable

Grounding

1/2 Jumper

Cabinet

EMP

Grounding clip

Grounding bar

1/2 Clamp

Tower Top

Amplifier

7/8 Cable

Machine house

1/2 Jumper

Antenna system


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Content

Antenna overviewAntenna specifications

Principle of antenna selection


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Radio propagation in cities

Environment features:

Densely deployed BTSsmall coverage area

Decrease over coverage and interference, increase

frequency reuse factor


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Antenna selection in cities

Polarization Dual-polarization (Installation space)

Direction Directional antenna (Frequency reuse factor)

3dB bandwidth 60~65(Control coverage)

Gain 15-16dBi

Tilt down angle Fixed electrical tilt down


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Radio propagation in suburb/rural area

Environment features: Loosely deployed BTS

light traffic

large coverage


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Antenna selection in suburb/rural area

Polarization Both dual-polarized and vertical

Direction directional

3dB bandwidth 90105

Gain16-18dBi directional

or 911dBi omni

Tilt down angle Mechanical tilt down; 50m high; null fill


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Antenna selection for highway


Direction Narrow beamwidth directional

3dB

bandwidth30

Gain 18dBi22dBi

Tilt down

angleNo tilt down


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Radio propagation in mountainous environment

Environment features:

Block by mountains

Big propagation loss

Difficult to cover


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Antenna selection in mountainous area


Direction Omni or directional

3dB bandwidth Big 3db verticle bandwidth

GainOmni (9-11dBi

Directional (15-18dBi

Tilt down angle Null fill & electrical tilt down


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GBO 006 E1 1 GSM Antenna System-63

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