RNP-Antenna_Principle_and_Selection_1.0.ppt

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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 1
WCDMA RNP Antenna
Principle and Selection
Internal

Review
Interface between radio transceiver and outside
propagation environment.
Antenna can transmit and receive radio waves.
Converts the RF currents to electromagnetic
(EM) waves;
Receives radio waves, and converts EM waves
to RF currents.

Objectives
 Learn the principle and classification of
antenna
 Know some of characteristics of antenna
 Study the rules for antenna selection
 Understand the antenna selection for different
scenarios
From this course, we will be able to:

Contents
Antenna Principle and Classification
Primary Technical Performances of the Antenna
Rules for Antenna Type Selection
Antenna Selection for Different Scenarios
Summary

Antenna location and function
Antenna and
feeder system
figure
Thunder
protector
Feeder(7/8“
)
Feeder
clip
Feeder
ladder
Grounded
clip
Connector, insulated airproof
tape, PVC insulated tape
Adjustable
support
Board
antenna
Pole(50~114mm)
Outdoor
jumper
Indoor jumper
Feeder
window
NodeB

 Based on the polarization mode:

Alternant circuit in the lead will radiate electromagnetic (EM) waves, the
radiation ability is related to the length and shape of lead.

When the length of lead is close to wave length, circuit in the lead will
increase greatly and radiate strong radio wave, we call this direct lead as pole.
Antenna Work Principle
positive
negative

Antenna Classification
 According to radiation direction

 According to polarization direction:

Antenna polarization direction: electric field vector is the
polarization direction of EM wave
vertical polarization horizontal polarization
+45 polarization -45 polarization

 According to polarization mode:

vertical polarization antennas (also called mono-polarization
antennas)

Cross polarization antennas (also called dual polarization
antennas).
single polarization (vertical) antenna
dual polarization(+-45) antenna

 According to the outlines
whip antenna plate antenna cap antenna paraboloid antenna

Contents
Antenna Classification and Classification
Primary Technical Performances of Antenna
Summary

Antenna Gain
 Gain is one of the most important indices of an
antenna. It indicates the antenna’s capability of
centralizing energy to a certain direction
dBi is defined as the energy centralizing capability of the
actual directional antenna (including omni antenna) in
relation to isotropic antennas, “i” means “isotropic”.
dBd is defined as the energy centralizing capability of the
actual directional antenna (including omni antenna) in
relation to dipole antennas, “d” means “dipole”.

Antenna Gain
 As a passive device, antenna itself cannot
increase the energy of transmitted signals. It
only can centralize the energy to a certain
direction by combining the antenna dipoles and
changing their feeding mode
¸ Isotropic
Dipole
Actual antenna
The actual antenna gain is 11dBi
11dBi
8.85dBd 2.15dB 2.15dBi ERP
EIRP

Antenna Pattern
 The graph describes the distribution of EM field of the
antenna transmission along the fixed distance on the
angular coordinates.
 A pattern presented by transmission field intensity is
called field intensity pattern, a pattern presented by
power density is called power density pattern, and a
pattern presented by phase is called phase pattern.
 Normally power density pattern is used in Mobile
communication system, it includes vertical pattern
graph and horizontal pattern graph

Symmetric half-wave dipole Pattern
Top view side view
directional antenna pattern
omni antenna pattern
Antenna Pattern

Antenna Pattern
 Beam width (BW) (called semi-power angle)
 Front-to-back ratio
 Zero-point filling
 Upper side lobe suppression

Relationship between Wave Width and
Gain
 Antenna is an energy-centralizing device. The
enhancement of transmission in one direction means the
reduction of transmission in other directions. In general, we
can enhance the transmission strength in a certain
direction by reducing the horizontal lobe width so as to
increase the antenna gain. Under a given antenna gain, the
horizontal BW is in reverse proportion with the vertical BW:
 
10 lg 32400
a
G  
  
 
 
Ga : antenna gain, dBi;
B: vertical BW, degree .
Θ : horizontal BW, degree.

Polarization Mode
 Polarization is the transmission performance
describing the vector direction of EM field
intensity. Unless specific state, the space
direction of electric field vector is the
polarization direction of EM wave. The vector
direction refers to the direction of maximum
transmission of antenna.

Polarization Mode
 Single polarization antennas in WCDMA system adopt
vertical polarization, while dual polarization antennas use
polarization diversity to minimize the negative effect of
multi-path fading in the mobile communication system so
as to improve the quality of receiving signals. Dual
polarization antennas in WCDMA system usually use
± 45° cross polarization mode.
+/- 45°)

Mechanical Down Tilt and Electric Down Tilt
Mechanical down tilt
electric down
tilt

Voltage Standing Wave Ratio (VSWR)
 When the input impedance is not consistent with the
characteristic impedance, the reflected wave and the
incident wave overlap on the feeder and form standing
wave. The ratio between the maximum value and the
minimal value of the adjacent voltage is VSWR. Big
VSWR leads communications distance shortened, at
same time reflection power returns to power amplifier
(PA) of transmitter. PA might be damaged.

9.5 W
80
ohms
50 ohms
Forward: 10W
Reflection: 0.5W
Voltage Standing Wave Ratio (VSWR)
If and respectively stand for the input impedance
and nominal impedance of the antenna, the reflectance
is
， where . The matching
feature of a port can also be indicated by Reflection
Loss . If
will be 13.98
A
 o
Z
o
A
o
A













1
1
VSWR

50
o
Z
1
:
5
.
1

VSWR
 
dB
L
R .
.
. .( ) 20 lg
R L dB   

Other Technical Performances
 Port Isolation
 Power Capacity
 Input Interface of the Antenna
 Passive Inter-modulation (PIM)
 Antenna Size and Weight
 Wind Load
 Working Temperature and Humidity
 Lightning Protection
 Three-Proof Capability

Contents
Summary

Principle for Antenna Beam Width
Selection
 Selection of beam width
horizontal beam : depends on the type design of
NodeB
vertical beam: depends on antenna gain
 In urban areas
3-sector vertex-excited NodeBs, 65° horizontal beam
width
6-sector vertex-excited NodeBs, 33° horizontal beam
width
 In suburban areas

Principle for Polarization Mode Selection
 urban area

dual polarization antennas
 open mountainous areas and rural
areas

vertical single polarization antennas

Principle for Downtilt Mode
Selection
Comparison between Mechanical Downtilt and Electric Downtilt
Comparison between Mechanical Downtilt and Electric Downtilt

Selection
Comparison between Preset Electricity Downtilt and Zero-Point Filling
Comparison between Preset Electricity Downtilt and Zero-Point Filling
 The use of preset electric downtilt can shorten
the coverage range of the main lobe if the cell
coverage is planed to small.
 Through zero-point filling, a kind of shaping
technology, we can obtain a good pattern. In this
case, the upper side lobe can be suppressed, so
this kind of antennas will influence other aspects.

Selection
Planning and Optimization of Downtilt Angle
Planning and Optimization of Downtilt Angle
 For an omni antenna, we cannot adjust the
mechanical downtilt angle, but we can select
preset electricity downtilt angle antennas.
 For a directional antenna, in different occasions,
requirements for the downtilt angle adjustment
range are different.

Principle for Front-to-back Ratio
Selection
 In occasions where NodeB sites are densely
distributed, if the back lobe is too big, it will be likely to
cause pilot pollution and the network quality will be
influenced. In urban areas, the antenna front-to-back
ratio should be 25dB. In suburbs or rural areas, the
≥
antenna front-to-back ratio can appropriately lower.
 The front-to-back ratio is in reverse proportion to the
beam width. The narrower the beam is, the higher the
front-to-back ratio is.

Principle for Antenna Size
Selection

Antenna size selection is mainly
Antenna size selection is mainly
related to the install ability
related to the install ability
 Firstly, the antenna size is related to
the technical level of manufacturers
 Secondly, the antenna size is related
to the antenna gain

Principle for Antenna Impedance Selection
 The input impedance of a combiner is 50Ω. In order
to reduce the standing wave ratio, the characteristic
impedance of an antenna should match with the
input impedance, namely, it should be 50Ω.
 General, the characteristic impedance can meet this
requirement, but attention should be paid to this
index during selection or certification of new
antennas.

Contents
Summary

Antenna Selection for Different
Scenarios
 In WCDMA system, antenna selection is very important.
Antennas should be selected based on the practical situations
such as the NodeB design, network coverage requirements and
interference conditions.
 Practical situations

In urban coverage

In sub-urban coverage

In rural coverage

In highway coverage

In indoor coverage

In offshore coverage

In tunnel coverage


In Urban Coverage
In Urban Coverage
Huawei Recommendation
Frequency range: 1710 ~ 2170 MHz/±45°dual
polarization / 65°horizontal BW/15 dBi
gain/preset 6°electrical DT or 0 ~ 10°adjustable
electrical DT and 0 ~ 15° adjustable mechanical
DT/upper side lobe suppression and zero-point
filling/25dB or higher front-to-back ratio.


In Suburban Coverage
In Suburban Coverage
Huawei Recommendation:
Select the specific antennas by referring to
antenna selection for urban areas and that for
rural areas depending on the distance between
two NodeBs and traffic density.
Antenna Selection for Different
Scenarios


In Rural Coverage
In Rural Coverage
 Recommendation (for directional antennas):
Working frequency 1710 ~ 2170 MHz / dual or
vertical polarization / 90° horizontal beam width /
18 dBi antenna gain / without preset downtilt / zero-
point filling
 Recommendation (for omni antennas): Working
frequency 1710 ~ 2170 MHz / vertical polarization /
11 dBi antenna gain / without preset downtilt / zero-
point filling


In Highway Coverage
In Highway Coverage
 Recommendation (for directional antennas):
Working frequency 1710 ~ 2170 MHz / vertical
polarization / 30° horizontal beam width / high gain
(for example: 21 dBi) / without preset downtilt / zero-
point filling
 Recommendation (for 8-figure-shape antennas):
Working frequency 1710 ~ 2170 MHz / vertical
polarization / dual 70° horizontal beam width / 14 dBi
antenna gain / without preset downtilt / zero-point
filling


For Highway Coverage
For Highway Coverage
 Recommendation (for heart-shape antennas):
Frequency range: 1710 ~ 2170 MHz/VP/2
10°horizontal BW / 12 dBi gain / without preset DT
zero-point filling
S0.5/0.5 NodeB configuration with high-gain
directional antennas
8-figure-shape antennas


In Indoor Coverage
In Indoor Coverage
 Recommendation (for omni antennas):
Frequency range: 800 ~ 2500 MHz/vertical polarization
(VP)/360°horizontal BW, 90° vertical BW/2dBi gain.
 Recommendation (for plate directional antennas):
Frequency range: 800 ~ 2500 MHz/vP/90°horizontal BW,
60°vertical BW/7dBi gain.
 Recommendation (for log-periodical antennas):
Frequency range: 800 ~ 2500 MHz/VP/55°horizontal BW,
50° vertical BW/11.5dBi gain.


In Offshore Coverage
In Offshore Coverage
 Antenna Recommended:
frequency range: 1710 ~ 2170
MHz
vertical polarization
30° horizontal BW
gain 21 dBi
without preset DT
zero-point filling


In Tunnel Coverage
In Tunnel Coverage
 Antenna Recommended
Frequency range: 800 ~ 2200 MHz
vertical polarization
55°/30°horizontal BW
log-periodical type with gain 11.5 dBi
(consider sharing with GSM/DCS systems).
 Leaky cable

Contents
Major Technical Performances of the Antenna
Principles for Antenna Type Selection
Summary

Summary
This course helps us:

To master antenna principle and classification

To master parameters of antenna

To understand the principles of antenna selection

To select antenna focusing on specific working environments

RNP-Antenna_Principle_and_Selection_1.0.ppt

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