Mobile communications is one of the communications fields that develop rapidly and energetically. The antenna builds the bridge between user terminals and base control devices. It is widely used in the mobile communications and the wireless access communication system. The rapid development of the antenna greatly promotes its technology innovation. It is important to deeply grasp the knowledge of the antenna, which is useful to: Install and maintain products. Promote the network planning. Chapter 1 Working Principle Chapter 2 Classification Chapter 3 Electrical Index Chapter 4 Mechanical Index When the conducting cable carries the alternating current, the electromagnetic wave radiation can be formed. If two conducting cables are close, the directions of their current are opposite, and the electromotive force is counteracted. Thus the radiation becomes week. If two conducting cables are open, the directions of their current are the same. Thus the radiation becomes strong. When the length of the conducting cable is like the wavelength, the current on the cable will be enhanced. Thus the radiation becomes strong. The straight conducting cable which can generate the strong radiation is called the dipole. The pole whose two arms are of the same length (1/4 Wavelength) is called as dipole or half-wave-length dipole.

1. ISSUE 2.1

2. Mobile communications is one of the communications
fields that develop rapidly and energetically. The
antenna builds the bridge between user terminals and
base control devices. It is widely used in the mobile
communications and the wireless access
communication system. The rapid development of the
antenna greatly promotes its technology innovation.
It is important to deeply grasp the knowledge of the
antenna, which is useful to:
• Install and maintain products.
• Promote the network planning.

3. Target
After learning the course, you can
learn the following of the antenna:
 Working principle
 Classification
 Electrical index and mechanical
index

4. Chapter 1 Working PrincipleChapter 1 Working Principle
Chapter 2 Classification
Chapter 3 Electrical Index
Chapter 4 Mechanical Index

5. Working Principle
8 Lightning arrester
Main feeder (7/8”)
5 Feeder fixing clip6 Cabling Rack (Frame)
4 Grounding device
3 Weather-proof connection PVC
material , Insulation sealing tape,
PVC insulation tape
1 Adjusting bracket
GSM/CDMA
Board-like
antenna
Antenna pole (φ50~114mm)
2 Outdoor feeder
9 Indoor super flexible jumper
7 Cable-through window
Main
equipment
of BTS
Diagram of the base antenna and
feeder system
Location and FunctionLocation and Function

6. Working Principle
 When the conducting cable carries the alternating
current, the electromagnetic wave radiation can be
formed.
 If two conducting cables are close, the directions of
their current are opposite, and the electromotive
force is counteracted. Thus the radiation becomes
week.
 If two conducting cables are open, the directions of
their current are the same. Thus the radiation
becomes strong.
 When the length of the conducting cable is like the
wavelength, the current on the cable will be
enhanced. Thus the radiation becomes strong.
 The straight conducting cable which can generate
the strong radiation is called the dipole.
 The pole whose two arms are of the same length
(1/4 Wavelength) is called as dipole or half-wave-
length dipole.

7. Working Principle
The pole whose two arms are of the same length (1/4
Wavelength) is called as dipole or half-wave dipole.
Half-Wavelength DipoleHalf-Wavelength Dipole

8. Working Principle
What is happen in these antennas?

9. Chapter 1 Working Principle
Chapter 2 ClassificationChapter 2 Classification
Chapter 3 Electrical Index
Chapter 4 Mechanical Index

10. Classification
Directional antenna Omni-directional antenna
Based on the Radiation DirectionBased on the Radiation Direction

11. Board-like antenna Cap-like antenna
Scourge-like antenna Paraboloid-like antenna
Based on the FigureBased on the Figure
Classification

12. Classification
 The electric field orientation of the radio wave is called the polarization.
 Vertical polarization means that the electric field orientation is upright to the terrestrial. Horizontal polarization means that
the electric field orientation is parallel to the terrestrial.
 When the vertical polarization wave is received by the horizontal polarization antenna, the current cannot be produced.
Receiving the wave is badly affected.
 The monopole antenna needs two main diversity antennas to enhance the receiving effectiveness. The dual-polarized
antenna, with the polarization of 45 angles, needs only one antenna.
Polarization ModePolarization Mode

13. Classification
Based on Polarization ModeBased on Polarization Mode

14. Chapter 1 Working Principle
Chapter 2 Classification
Chapter 3 Electrical IndexChapter 3 Electrical Index
Chapter 4 Mechanical Index

15. Electrical Index

16. Electrical Index
Orientation of half-wave
dipole
Top view Side-looking
Orientation of omni-directional antenna
Diagram of DirectionsDiagram of Directions
Orientation of directional antenna

17. Electrical Index
 The units of the antenna gain are dBi and dBd.
 dBi: Gain based on the isotropic radiator reference
 dBd: Gain based on the dipole reference
 The value difference between the two units is 2.15
dB.
 Gain of antenna compared with dipole is denoted by
dBd.
 Gain of antenna compared with isotropic radiator is
denoted by dBi.
Antenna Gain

18. Electrical Index
Diagram of DirectionsDiagram of Directions
 How to read the direction?
 Horizontal
 Vertical
 Main lobe
 Minor lobe
 Front-to-back
 Nulls
 HPBW (Half Power Beam width)

19. Electrical Index
 Beam width, front-to-back rejection ratio, null filling, upper
side lobe suppression

20. Electrical Index
Mechanical down tilt
Electrical down tilt
Mechanical Down Tilt andMechanical Down Tilt and Electrical Down Tilt

21. Electrical Index
9.5 W80
ohms
50 ohms
Forward: 10W
Back: 0.5W
VSWR: Stand Wave Ratio
Reflect Index : r
Import impedance : Za characteristic: Zb
r=|Za - Zb| / |Za + Zb|
VSWR = (1+|r|) / (1-|r|)
RL(Return Loss)=20lg |r|
Normal Value: VSWR<1.5dB ; RL(dB)<13.98dB

22. Chapter 1 Working Principle
Chapter 2 Classification
Chapter 3 Electrical Index
Chapter 4 Mechanical IndexChapter 4 Mechanical Index

23. Mechanical Index
 Antenna input
 Antenna size
 Antenna weight
 Wind load
 Working temperature
 Humidity
 Thunderbolt protection
 三防能力

24. Chapter 1 Working Principle
Chapter 2 Classification
Chapter 3 Electrical Index
Chapter 4 Mechanical Index

25. Questions
 What are the types of the antennas by signal radiation?
What are the types of the antennas by appearance?
 What are the main electrical indexes of the antenna?
 What are the main mechanical indexes of the antenna?
 What are the types of the distribution system?

26. Course Summary
 Working principle
 Classification
 Electrical index
 Mechanical index
SummarySummary