Antennas for GSM System

Contents

Base station antenna specification and meanings

Antenna types and trends

(Technical Data)

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（ Electrical properties ）• Operation Frequency Band• Input impedance• VSWR• Polarization• Gain• Radiation Pattern• Horizontal/Vertical beamwidth • Downtilt• Front/back ratio• Sidelobe suppression and null filling• Power capability• 3rd order Intermodulation• Insulation

（ Mechanical properties ）• Size• Weight• Radome material• Appearance and color• Working temperature• Storage termperature• Windload• Connector types• Package Size• Lightening

Electrical properties

Wavelength

1/2 Wavelength

1/4 Wavelength

1/4 Wavelength

1/2 Wavelength

Dipole

（ Dipoles ）

1800MHz ： 166mm

900MHz ： 333mm

1 个 dipole (received power) ： 1mW

Multiple dipole matrixReceived power ： 4 mW

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

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

Sector antennaReceived power ： 8mW

Omni directional arrayReceived power ： 1mW

(Overlook)

Antenna

（ Frequency Range ）

• GSM 900 : 890-960MHz• GSM 1800 : 1710-1880MHz• GSM dual band : 890-960MHz &

1710-1880MHz• eg.824-960MHz ， 1710-

1900MHz

（ BANDWIDTH ） = 960 - 890 = 70MHz

Optimum 1/2 wavelengthfor dipole at 925MHz

at 960MHz

Antenna Dipole

at 890MHz

（ Impedance ）

• 50

Cable

50 ohms

Antenna 50 ohms

9.5 W80

ohms50 ohms

Forward: 10W

Backward: 0.5W

Return Loss ： 10log(10/0.5) = 13dB

VSWR (Voltage Standing Wave Ratio)

（ VSWR ）

1.5=(VSWR-1)/(VSWR+1)RL=-20lg

（ Polarization ）

Vertical Horizontal

+ 45degree slant - 45degree slant

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

（ Linear,vertical ）（ dual linear 45 slant ）

Dipole

Ideal radiating dot source(lossless radiator)

eg: 0dBd = 2.15dBi

dBd and dBi

2.15dB

（ Pattern ）

（ Beamwidth ）

120° (eg) Peak

Peak - 10dB

Peak - 10dB

10dB Beamwidth

60° (eg) Peak

Peak - 3dB

Peak - 3dB

3dB Beamwidth

（ 3dB Beam width Horizontal ）

• Directional Antenna ： 65°/90°/105°/120 °Omni ： 360°

（ 3dB Beam width Vertical ）

Directional ： Omni-directional ：

（ Down Tilt ）

Mechanical down tiltFixed electronic down tiltAdjustable electronic down tilt

Demonstration of Electronic Down-tilt

Non down tilt Electronic downtilt Mechanical downtilt

(Electronic and mechanical downtilt)

（ Front to Back Ratio ）

Ratio of maximum main lobe to maximum side lobe

F/B = 10 log(FP/BP) typically ： 25dB

Back power Front power

（ Upper Side lobes Suppression & Null Fill ）

（ Side lobes ）

（ Permitted Power ）

Continuous :25-1500 watts

peak :n2p

（ Third Order Intermodulation ）

IMD@243dBm f1, f2, 2f1-f2, 2f2-f1

913MHz,936MHz,959MHz,982MHz

1000mW ( 1W) 1mW

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

（ Isolation ）

Mechanical properties

（ Dimensions ）

LWHLength ： connected with vertical bandwidth and

gainWidth ： connected with horizontal bandwidthHeight ： connected with techniques adopted

（ Weight ）

Affecting transmission and deploy

（ Radome Material ）

PVC, FiberglassAnti-temperature 、 water-proof ， anti-

aging ， weather resistant

（ Colour ）Good-looking,

environment-protecting

（ Operating Temperature Range ）

Typical range ： -40°C — +70°C

（ Storage Temperature Range ）

Typically ： -40°C — +70°C

（ Wind Load ）

Eg: 83N at 160 km/h

（ Connector Type ）

7/16”DIN ， N ， SMA female

（ Mast ）

Mast diameter 45-90mm

（ Lightening Protection ）

Direct Ground

(Antenna Types and Development )

(Antenna Types)By frequency band: GSM900, GSM1800, GSM900/1800

By polarization: Vertical, Horizontal, ±45º linear

polarization, circle polarization

By pattern: Omni-directional, directional

By down-tilt: Non, mechanical, electronic

adjustment, remote control

By function: Transmission, receiving, transceiving

(Antenna Development Trend)

Broad bandMultifunctionalHigh Integrity

ONE ANTENNA FOR MULTIPLE BANDS

870-960MHz and 1710-1880MHzExtended band option with 806-960MHz Dual slant ±45º polarisation65º horizontal beamwidthBand independent Teletilt™ control17dBi gain in both bandsDiplexed or Non-Diplexed versionsMechanical downtilt mounting option

7/8” （ MAIN FEEDER ）

1/2” （ JUMP CABLE ）

7/16”DIN-F （ DIN CONNECTOR ）

7/16”DIN-M （ DIN & N CONNECTOR ）

Lightening Arrestor

Rf port 2

Grounding

（ ACCESSORIES ）（ Trimming Tool or Hand Tool Kit ）（ Clamp ）（ Earthing Kit ）（ Wall Glands ）（ Hoisting Stocking ） ( Universal Ground Bar)

Antenna

7/16 Din Connector

7/8“ Cable

Grounding

1/2“ Jumper

Cabinet

EMPGrounding clip

Grounding bar

1/2 Clamp

Tower Top Amplifier

7/8“ Cable

Machine house

1/2 Jumper

Thank you