rf parts and antenna issue2 0

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Internal

OMF 000004Radio Frequency Part and

Antenna

ISSUE 2.0


RF components are widely used in

wireless system, and effect performance

of network


Upon completion this course, you will be able to:

Understand the structure and features of

combination unit

Master the key specifications of antenna

Be able to choose the suitable type of RF

component


Chapter 1 Chapter 1 RF Part in BTSRF Part in BTS

Chapter 2 Chapter 2 AntennaAntenna

Chapter 3 Chapter 3 Feeder and TTAFeeder and TTA


RF Device of BTS

Antenna

TTA

Antenna stand

Jumper between antenna and TTA

Jumper between TTA and feeder

Feeder

Lightening arrester

Jumper between lightening arrester and cabinet

BTS312 cabinet

SWITCH BOX

FAN BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

T

M

U

T

E

S

T

E

U

T

E

U

C

D

U

C

D

U

T

R

X

T

R

X

T

R

X

T

R

X

C

D

U

C

D

U

T

R

X

T

R

X

T

R

X

T

R

X

C

D

U

C

D

U

TDU

FAN BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

TR

X

T

R

X

T

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T

R

X


Introduction

RF device in BTS includes two parts

Indoor: combiner and splitter unit

For example: CDU module, SCU module and EDU module

Outdoor: antenna, feeder, TTA (tower top amplifier), jumper and

lightning arrester


Function of Combiner and Divider

Use one antenna to support multiple TX/RX

signals, decreases the amount of antenna and

feeder

Complete duplexer of TX/RX and combine TX

signal filter, amplify and split the RX signal

Provide power for TTA


CDU (Combining and Divider Unit)

Tx1

Tx2

Tx_CombTx_Dup

combiner duplexer

divider

divider

amplifier

filter

Rx1Rx2Rx3 Rx4

Rx5Rx6Rx7Rx8

HL_out

HL_in

RxD_outRxD

Tx/Rx_ANT


SCU (Simple Combiner Unit)

TX1

TX2

TX3

TX4

TX -Comb

combiner

combiner

combiner


EDU (Enhance Duplexer Unit)

Tx1 duplexer

divider

amplifier

Rx1

Rx2

Tx/Rx_ANT1

divider

amplifier

Rx1

Rx2

duplexer Tx/Rx_ANT2Tx2


Comparison among Different Combining Units

combine mode

typical loss value of TX(dB)

price comparison

(per TRX)

CDU

combine two TX signal

one step 3dB combiner

4.5 middle

SCU

combine four TX signal

two step 3dB combiner

6.8 low

SCU+CDU

combine four TX signal

two step 3dB combiner

8 low

EDU no combinerdouble duplex 1 middle

Double CDU( with combiner)

no combinerdouble duplex 1 high

Double CDU(without combiner)

combine two TX signal

double duplex4.5 middle


New Type CDU&ESCU

ECDU

The structure is the same as CDU's, but increase MAX. input

power. It can bear up to100W input RF power

ESCU

The structure is the same as CDU's, but increase MAX. input

power. It can bear up to100W input RF power


Chapter 1 Chapter 1 RF Part in BTSRF Part in BTS

Chapter 2 Chapter 2 AntennaAntenna

Chapter 3 Chapter 3 Feeder and TTAFeeder and TTA


What is Antenna?

Radiate and receive radio wave ,convert high frequency current

to electromagnetic wave when transmitting, and convert

electromagnetic wave to high frequency current when receiving

B lah

blahb la h bl ah


Classification

Classify by working band: UHF, VHF, microwave, etc.

Classify by radiate pattern: omni, directional

Classify by structure: line, pane, parabola feed

Classify by polarization: vertical and horizontal

Classify by outline: line and pane


omni directiondirectional Antenna

Radiate Pattern


Outline


vertical polarization Omni antenna

dual polarizationdirectional antenna

Polarization

vertical polarization directional antenna


Function

Convert high frequency current to electromagnetic wave when

transmitting

Convert electromagnetic wave to high frequency current when

receiving

Antenna can not amplify the transmission power, just concentrate

RF power to one direction

horizontal section Vertical section


Radiate Pattern

Omni antenna

lobe

Direction

antenna lobe


Radiate pattern


Dipole and Isotropic

Dipole

1/4 wave length

1/4wave length

1/2wave length

Isotropic

Ideal radiator with same ability on all direction!


Gain

The radiation ability of certain antenna overtop dipole or isotropic

Indicates the antenna feature of electromagnetic radiation in specific

directions

Unit: dBi/dBd

theory source

l/2 antenna

Direction antenna

dBd

dBi

dBi = dBd+2.15


Forward to Back Ratio

The ratio of main lobe signal strength to back lobe

This value is within 18—45dB. In urban, it is suggested to use

the antenna with high F/B ratio


Beam Angle

HPBW: Half Power Beam Bandwidth

Lobe angel between two points, the power of which reduce to

the half of that of the maximum radiate direction

Vertical HPBW and Horizontal HPBW

60° (eg) Peak

- 3dB

- 3dB

15° (eg) Peak

Peak - 3dB

Peak - 3dB


Down title

To control coverage

To decrease inter modulation

Realization: electron and mechanism


mechanism

electron

Down tilt


Effect of Electron Down title

No Down tilt Electron Down tilt


Effect of Mechanism Down tilt

No Down tilt Electron Down tilt


Effect of different methods

10°(E) 10°(M)6°(E)+ 4°(M)


Polarization

The direction of electro - vector radiated by antenna. The

vertical polarization wave is vertical with the plane of ground,

and the horizontal polarization waves parallel with the plane of

ground

Single antenna has only one polarization direction.

Dual polarized antenna contains two single - polarized antenna

in one entity. Dual polarization antenna usually adopts +45/-45

degree orthogonal polarization.

-


Polarization

VERTICAL HORIZONTAL

+ 45 - 45


Dual Polarization

V/H +/- 45°


Port IsolationThe isolation among ports should be more than 30 dB. for multi-ports antenna, Such as dual band, dual polarization antenna

1000mW (1W) 1mW

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


Null Filled

It shall apply null filled technology when zero depth is less

than main beam for 26dB.

High gain antenna especially adopt null filled technology to

effectively improve the nearby coverage


Main to lower side

Main to upper side

Upper Side Lobe Suppression


Coupling Between Antennas

main lobe

5 .. 10

Horizontal separation

Sufficient decoupling distance: 5-10λ

Antenna patterns become superimposed if

distance is too close

Vertical separation

Decoupling distance:1λ can provide better

RX /TX decoupling

Minimum coupling loss


Installation Examples Recommended decoupling

TX - TX: ~30dB

TX - RX: ~40dB

Horizontal decoupling distance

depends on

Antenna gain

Horizontal rad. pattern

Omni-directional antenna

Use vertical separation for RX and

TX

Use vertical separation (“fork”) for

RX and diversity RXVertical decoupling is much more effective

0,2m

Omni-directional.: 5 .. 20mdirectional : 1 ... 3m


Antenna Installation

Coupling loss (dB):

Lv=28+40log(k/λ) (vertical installation)

Lv=22+20log(d/λ)-(G1+G2)-(S1+S2) (horizontal installation)

Λ: wave length

K: distance at vertical

D: distance at horizontal

G1 、 G2: gain

S1 、 S2: Relative gain at line connected two antenna


Distributed Antenna System

BTSBTSPower

splitterPower splitter

Power splitter

coupling

coupling

coupling

coupling

Smallantenna

Small

antenna

Smallantenna

Smallantenna

Smallantenna

Smallantenna

Smallantenna

coupling

Dual direction

amplifier

Dual direction amplifier


Symmetry and Asymmetry Network

Tx/Rx

3

3

3

3

3

3

3

3

3

3

3

Tx/Rx

1.36

0.510

100.5


Dual direction

amplifier


Optical Fiber Distributed Antenna

The optical fiber repeater is mainly adopted in the case

of wide coverage and long distance transmission

signal

Optical transceiver Optical transceiver

Optical transceiver

Optical transceiver

transceiver

transceiver


Leaky Cable

Coaxial cable with perforated leads

It is mainly adopted for tunnel, metro and with high cost of

equipment and installing

Tx/Rx

Matching load

Matching load



Power splitter


Leaky cable

Coaxial cable with perforated leads

Produce constant field-strength along cable runs

Work at wide-band

Radiating loss become higher with high frequency

Very large bending radius

Formerly often used for tunnel coverage

Expensive


Feature of Leaky Cable

Transmission loss per hundred meter

Typical value : 10~40 dB per 100m

Couple Loss at 1 meter distance

Typical value 55 dB (at 1m)

How to calculate strength with leaky cable?


Comparison with Distributed Antenna

type leaking fiber coaxial fiber optical

design agility good good not good

cost high low high

Complexity of installing

high low low

loss of transmission

high high low

power supply not needed not needed needed

reliability high high low

applicability metro, tunnelhigh building,

commercial area

far area coverage


Chapter 1 RF Part in BTSChapter 1 RF Part in BTS

Chapter 2 AntennaChapter 2 Antenna

Chapter 3 Feeder and TTAChapter 3 Feeder and TTA


Tower Top Amplifier

Amplify uplink weak signal, then:

Balance uplink and downlink

Compensate loss of feeder

Simplex TTA duplex TTA triplex TTA


Triplex Tower Top Amplifier

Low noise amplifier

TX filter

bypassBias Tee

BTS

triplex TTA

antenna

DC

RX filterRX filter


Data Configuration of CDU Turn on power of TTA in CDU before installation

TTA switch is in rear panel of CDU

Configuration alarm threshold of TTA current before installation

TTA current switch is in rear panel of CDU

Configuration attenuation factor of receive signal on consol

attenuation factor of receive signal

=TTA gain – feeder loss

Simplex TTA gain:14dB, triplex TTA gain:12dB

Don’ t use TTA if not necessary

For the convenience of installation

To get better lighting -proof effect


Power Switch and Current Limit

Rear panel of KMW CDU

TTAM TTAD

OFF OFF

TTAM TTAD

123TTAM TTAD

OFF OFF

123

TTAM: power switch of main TTA switch

TTAD: power switch of diversity TTA

select current limitTTAM TTAD


Power Switch and Current Limit

MA

IN

01 2

3

012

3

DIV

ER

SE

Note:

MAIN：main TTA switch

DIVERSE：diversity TTA switch

Rear panel of COM DEV CDU

01 2

3

012

3

01 2

3

012

3


Feeder Feeder selection

Type : 1/2” 、 7/8” 、 5/4”

Select 5/4” in the case of feeder length is more than 80 m

and otherwise select 7/8” in 900MHz

Select 5/4” in the case of feeder length is more than 50 m

and otherwise select 7/8” in 1800MHz

Feeder curvature should not be so big, outer conductor

should be connected to earth

LG0.251.156.74.47HFC22D -A(7/8 )

6090.31.156.465.874.03SYFY -50 -22(7/8 )

ACOME0.221.156.64.3M1474A(7/8 )

ANDREW0.381.154.774.313.172.98LDF6 -50(5/4 )

ANDREW0.251.156.465.874.34.03LDF5 -50A(7/8 )

2,0001,7001,000890manufacturerBend

Radius (m)VSWRLOSS dB/100m ， (MHz)TYPE


In this course, we have learned:

CDU structure and loss

SCU structure and loss

Antenna type and feature

TTA

SummarySummary

www.huawei.com

Thank You

rf parts and antenna issue2 0

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