Tri Nopiani Damayanti,ST.,MT

Dadan Nur Ramadan,S.Pd,MT

Yuyun Siti Rohmah, ST.,MT

Suci Aulia,ST.,MT

ANTENA PADA SISTEM SELULER

Teknik Transmisi Seluler

(DTG3G3)

Macam-Macam Jenis Antena yang ada di BTS

1) Omnidirectional

Tx

Rx

Rx

Pada kondisi awal biasanya digunakan pola omnidirectional (tergantung demand) di gunakan pada lingkup

yang mempunyai base station terbatas dan cenderung untuk posisi pelanggan yang melebar

Antena yang memiliki pola pancaran sinyal ke segala arah dengan daya sama

Menghasilkan cakupan area yang luas, gain dari antena omnidirectional harus memfokuskan dayanya

secara horizontal (mendatar,dengan mengabaikan pola pemancaran ke atas dan ke bawah,sehingga antena

dapat di letakan di tengah-tengah base station

Keuntungannya jenis ini adalah dapat melayani jumlah pengguna yang lebih banyak

kesulitannya adalah pada pengalokasian frequensi untuk setiap sel agar tidak terjadi interferensi

Macam-Macam Jenis Antena yang ada di BTS

2) Sectoring 120o

3) Sectoring 60o Kegunaan dari pola Sectoring

a. Menambah kapasitas

b. Mengurangi interferensi

• Keuntungan antenna sektoral mempunyai gain

yang lebih besar daripada antenna

omnidirectional. Biasanya antenna sektoral

mempunyai gain antara 10-19 dBi

RBS / BTS

= Radio Base Station / Base Transceiver Station = Merupakan perangkat transceiver yang berhubungan dari /

ke pelanggan (Interface / repeater antara MS dan MSC) . = Elemen-elemen RBS :

Transceiver Control Unit / BSC / Base Station Controller Antena

Data terminal

single

antenna

base station

housingjalur transmisi

gelombang

mikro menuju

BSC

site 3 sektor dengan 7

array antena tiap

sektornya

Bagaimana bentuk antena pada lokasi site ?

Basic Antennas System

l/2 G=2.14 dBi Z= 73 W

a. Dipole

l/4

G=4 dBi Z= 36 W

b. monopole

Ground plane

c. Loop Ground plane

conductor Feed point

d. Microstrip/ patch

dielectric

l/2

l/2

l

Base Station Antenna (1)

• Use antenna with higher gain • Could be omnidirectional or sectoral depending on cell type • Collinear antenna:

S

2l

2l

4l

feeder

line

Omnidirectional

Radiation

Pattern

boresight

main lobe

side lobe (elevation)

Base Station Antenna (2)

• Log periodic dipole array (LPDA)

Dipoles Transmission

line

- BW is smaller than LPDA

- typical gain 12 – 14 dB

Reflector Driven element (dipole)

Directors

• Yagi antenna

Directional Radiation

Pattern

main lobe

main lobe side lobe back lobe

- very wide BW, with constant SWR

- typical gain 10 dBi

Sector Antennas Reflectors And Vertical Arrays

Typical commercial sector antennas

are vertical combinations of dipoles,

yagis, or log-periodic elements with

reflector (panel or grid) backing:

Vertical plane pattern is determined by number of

vertically-separated elements

varies from 1 to 8, affecting mainly gain and

vertical plane beamwidth

Horizontal plane pattern is determined by:

number of horizontally-spaced elements

shape of reflectors (is reflector folded?)

Sector Antennas Reflectors And Vertical Arrays

Typical commercial sector antennas

are vertical combinations of dipoles,

yagis, or log-periodic elements with

reflector (panel or grid) backing:

Vertical plane pattern is determined by number of

vertically-separated elements

varies from 1 to 8, affecting mainly gain and vertical

plane beamwidth

Horizontal plane pattern is determined by: number of horizontally-spaced elements

shape of reflectors (is reflector folded?)

This is inside the GSM Dual band

antenna.

left side is for 900MHz band.

Right side array is for 1800MHz.

Is a Patch Panel antenna.

TILTING ANTENA

Tilting antena adalah suatu pengaturan kemiringan antena yang berfungsi untuk

menetapkan area yang akan menerima cakupan sinyal

1. TILTING MEKANIK

Tilting mekanik adalah mengubah

kemiringan antena dengan cara

mengubahnya dari sisi fisik antenna.

Rigger memiliki alat ukur tilt meter yang

memperlihatkan derajat kemiringan antena.

2. TILTING ELEKTRIK

Tilting elektrik adalah mengubah coverage antenna dengan cara mengubah fasa antenna,

sehingga terjadi perubahan pada beamwidth antenna. Mengubah fasa antenna dapat

dilakukan dengan cara mengubah setingan elctrical tilt pada antenna, yaitu 1,2,3 dst.

Pengaturan tilt elektrik biasanya berada di bagian bawah antena.

The electrical tilt portion of the GSM panel antenna

Electrical tilt of GSM patch panel antenna.

This is the electrical tilt image. The cable distance between the input feed and

the antenna element is varied by a slider. This rotation can be controlled

remotely also by using a motor.

These are the parts of parabolic microwave antenna used in the backhaul

between BTS and BSC.

Contoh di lapangan

Cell A

Cell B

Cell C

ATP BTS 2G

Telkomsel C Project

Site ID : JKU540

Site Name : MAHONIUJUNGMD

Site Location : Jl. Mahoni selatan Gg A RT.14/10

Jakut

BTS Type : BTS3900A Outdoor

Remote Electrical Tilt

(RET) System

Types Of Downtilt

Antenna Downtilt

Antenna Downtilt : Reduce Interference

Antenna Downtilt : Avoid Overshoot

Performance Criteria of Antenna (1)

• Antenna pattern, defined at azimuth and elevation orientation either omni or bidirectional antenna

• Main lobe & side lobe, the lower side lobe the better resistance to interference

• Input impedance, usually complex matching input impedance and feeder line impedance is very critical to have maximum power transfer from feeder to antenna

• Beamwidth, usually defined as angular separation where there is 3 dB reduction from bore-sight

• Directivity & Gain, is ratio of radiation intensity at wanted direction and coverage radiation intensity over all direction

• Bandwidth, define operating range of antenna, limited by SWR. A typical BW is for SWR 1:1.2 at the band edge.

• Polarization, defined by orientation of

Performance Criteria of Antenna (2)

• Front to Back Ratio (FBR), is ratio between main lobe & back

lobe, very impotant for directional antenna.

THANK YOU FOR YOUR TIME