This document discusses principles of antenna selection and provides guidance on selecting antenna models for different scenarios. It begins with an overview of antenna principles including dipole antennas and factors that influence antenna gain. It then discusses key parameters to consider when selecting antennas such as radiation pattern, gain, beamwidth, downtilt mode, polarization, frequency range, and impedance. The document provides recommendations for selecting antenna models based on scenarios such as downtown areas, suburbs, water surfaces, narrow land strips, and complicated terrain. It also discusses downtilt techniques and provides examples of specific antenna models.

1. UMTS Antenna Model Selection
ZTE University

2. Content
Principles of Antenna
Model Selection of Antenna

3. Principles of Antenna (1)
 What is antenna?
 Antenna converts the electrical signals from the conductive
wire into radio wave and transmits it into the air …
 Antenna collects the radio wave and converts it into
electrical signals
Blah blah
blah bl ah

4. Principles of Antenna (2)
 When the conductive wire has alternating current, it can
form radiation of electromagnetic wave, with the
radioactive capacity related to the length and form of the
conductive wire.
 When the length of the conductive wire increases to a
degree comparable to wavelength, the current on the
conductive wire sharply increases, forming strong
radiation. Generally the straight conductive wire above
that can form noticeable radiation is called dipole .

5. Principles of Antenna (3)
 A dipole with the two rods of the same length is
called symmetrical dipole, or 1/2 wavelength dipole.
A single 1/2 wavelength symmetrical dipole can be
used independently, or multiple 1/2 wavelength
symmetrical dipole can form an antenna array.
Wavelength
1/2 Wavelength
1/4 Wavelength
1/4 Wavelength
1/2 Wavelength
dipole

6. Outer View of Antenna (1)
 Outdoor NodeB patch directional antenna

7. Outer View of Antenna (2)
Indoor ceiling-mount antenna Indoor wall-mount antenna
 Indoor antenna

8. For example, 1 symmetrical dipole
Receiving power: 1mW
Antenna array of 4 symmetrical dipoles
Receiving power: 4 mW
GAIN= 10log(4mW/1mW) = 6dBd
The high gain of the patch antenna is formed by the antenna array of multiple
basic dipoles
Gain of Antenna

9. Gain of Antenna
 The definition of the gain of an antenna is related to the 1/2
wavelength dipole or the omni radiator.
 The omni radiator assumes that the radiation powers in all
directions are equal. The gain of the antenna in a certain
direction is a value of the field strength generated in this
direction over the intensity by the omni radiator in this direction.
 Generally the gain of the antenna has two units: dBd and dBi.
 dBi indicates the field strength in the direction of the largest
radiation of the antenna, compared with the reference value of
the omni radiator.
 The gain of the antenna compared with the 1/2 wavelength
dipole is indicated with dBd.
 0dBd=2.15 dBi

10. Difference of dBd and dBi
2.15dB
Pattern radiation of a
single symmetrical dipole
A omni homogeneous
radiator has the same
radiation in all directions
Gain of an antenna compared with a
symmetrical dipole is indicated with “dBd”.
Gain of an antenna compared with an omni
homogeneous radiator is indicated with “dBi”.
For example: 3dBd = 5.15dBi

11. Antenna Direction
 The antenna direction refers to the capability of
radiating electromagnetic wave in a certain direction.
 For the receiving antenna, pattern means the
receiving capability of the wave promulgated from
different directions.
 The characteristic curve of antenna direction is
usually indicated with pattern.
 Pattern is employed to describe the capability of
transmitting/receiving electromagnetic wave in all
directions in the space.

12. Antenna Pattern
Top view

13. 120
(eg)
Peak
- 10dB point
- 10dB point
60 (eg) Peak
- 3dB point
- 3dB point
15 (eg) Peak
Peak - 3dB
Peak - 3dB
32 (eg) Peak
Peak - 10dB
Peak - 10dB
Vertical pattern
3dB beamwidth
Horizontal
pattern
10dB beamwidth
Beamwidth of Antenna

14. Horizontal Lobe 3dB Width

15. Directional antenna Omni
antenna
Vertical Lobe 3dB Width

16. Work Frequency Range of Antenna
 In disregard of transmitting or receiving antenna, it
always works within a certain frequency range.
With the considerations of out-of-band anti-
interference capacity, the usual practice is to
select the bandwidth of the antenna that just
meets the frequency requirements.
At 850MHz, the 1/2
wavelength is best
At
890
MHz Antenna
dipole
At
820
MHz

17. Polarization of Antenna
Vertical
polarization
Horizontal
polarization
+ 45 tilted polarization - 45 tilted polarization

18. Dual-polarization Antenna
 The dual-polarization consists of two Antenna with
orthogonal poles within the same radome. The adoption
of dual-polarization antenna can sharply reduce the
number of Antenna, streamline the installation
engineering of antenna, lower cost, and save space in
antenna installation.
V/H
(vertical/horizontal)
Tilt (+/- 45)

19. Antenna Beam Downtilt
 Applied to suppress coverage and reduce cross-
modulation
 Two modes: Mechanical downtilt and electrical
downtilt

20. Impact of Down-tilt on Coverage

21. Beam Downtilt
 The purpose of the downtilt technology is to tilt the main
beam to reduce the radiation level to the adjacent
coverage cells. In the case, though the frequency level at
the edge of the cell is reduced, the interference level is
much lower than the frequency level.
No downtilt
Electrical
downtilt
Mechanical
downtilt

22. Phase Shifter
Principle of Electrical Downtilt

23. Electrical Downtilt and Mechanical Downtilt

24. Front-to-Back Ratio
 In the antenna pattern, the ratio of max. value of
front and back lobes is called front-to-back ratio .
The front-to-back ratio of the outdoor NodeB
antenna is preferably generally larger than 25dB.
Front powerRear power

25. Input Impedance of Antenna
 The ratio of the signal voltage and the signal
current of the antenna and the feeder connection
points, or the two ends of the feeding points, is
called impedance of antenna.
 Input impedance has resistance component and
reactance component. For any antenna, we make
adjustment through the antenna impedance.
Within the required work frequency range, the real
part of impedance is very small and imaginary part
is very close to 50 , so that the antenna
impedance is Zin = Rin = 50 . This is necessary
to ensure the impedance of antenna and that of
feeder to be well matched.

26. VSWR
 The generation of VSWR : As the incident wave power is
transmitted to the antenna input end and is not
completely absorbed (radiation. Reflection wave is
generated and stacked to generate VSWR.
 The value of VSWR is between 1 and infinite. VSWR is 1,
indicating full match. VSWR is infinite, indicating full
reflection and full mismatch.
9.5 W80
ohms
50 ohms
Forward: 10W
Backward: 0.5W

27. Reflection coefficient :
||=|(Za-Zo)/(Za+Zo)|，
Za: Input impedance
Zo: Antenna standard input impedance
VSWR=(1+||)/(1-||).
RL=-20lg||,
eg:
if VSWR=1.5, then RL=-13.98dB.
VSWR

28. Side Lobe Suppression and Null Fill-in

29. Side Lobe Suppression and Null Fill-in

30. Content
Principles of Antenna
Model Selection of Antenna

31. Parameters Related to Antenna Model Selection
 In selecting Antenna, a large number of Antenna
is involved.
 Such parameters as radiation pattern, gain,
horizontal lobe width, vertical lobe width, and
downtilt mode are selected according to the
terrain, ground objects, height of NodeB, and
coverage radius in the coverage.
 The selection of other parameters is relatively
simple and done according to the designed
system.

32. Polarization Mode (1)
 NodeB antenna adopts linear polarization mode.
 In particular, single-polarization antenna adopts
vertical linear polarization, whereas dual-
polarization antenna adopts 45 dual-linear
polarization.

33. Polarization Mode (2)
 In downtown of cities, the number
of NodeB is large, and the
coverage radius of each NodeB is
small. It is suggested to adopt dual-
polarization antenna.
 In suburb and countryside, the
number of NodeB is small and the
coverage radius is large relatively.
Space diversity can be adopted to
enhance the receiving effect of the
NodeB. The single-polarization
antenna can be adopted.

34. Model Selection of Antenna
 Downtown of
cities

35. Suggestions for different scenarios:
Model Selection of Antenna
 Downtown of cities
The S111 NodeB in downtown of cities generally adopts
Antenna with 65 horizontal lobe width and 7 to 10
vertical lobe width, with the gain of the Antenna ranging
within 15 to 18 dBi. For the S110 or S100,the Antenna
with 65, 90 or wider horizontal lobe width. The selection
is based on the actual situation. The selection of vertical
lobe and gain is the same as the S111 station. For omni
station, Antenna with small gain and electronic downtilt
are selected.

36. Model Selection of Antenna
 Suburb and
countryside

37. Model Selection of Antenna
 Suburb and countryside
Directional Antenna adopt Antenna with 90
horizontal lobe width and 5 to 7 vertical lobe
width, with the gain ranging within 15 to 18 dBi.
Omni Antenna adopts Antenna with 5 to 7
vertical lobe width, with the gain ranging within 9
to 12 dBi.

38. Model Selection of Antenna
 Water surface

39. Model Selection of Antenna
 Water surface (large lake and sea surface), gobi,
and desert
 Directional antenna: If the coverage is relatively
open and wide, Antenna with 90 or 105
horizontal lobe width and 5 to 7 , with the gain
ranging within 14 to 18dBi ,vertical lobe width can
be selected. If the coverage distance is long but
the width is narrow (e.g., lake and terrain factors),
the 65 narrow beamwidth antenna can be
selected.
 Omni antenna: The Antenna with 5 to 7 vertical
lobe width and gain ranging within 9 to 12dBi can
be selected

40. Model Selection of Antenna
 Narrow land strips

41. Model Selection of Antenna
 Narrow land strips (such as highway and railway)
 Antenna for highway and railway are selected
according to the coverage line distance and
shape of the highway and railway concerned.
 If the line is relatively straightforward, high-gain
Antenna with 20 to 30 horizontal lobe width and
5 to 7 vertical lobe width can be selected.
 If the line is a curve in a large amplitude, Antenna
with 65, 90, or even larger horizontal lobe width,
and with 5 to 7 vertical lobe width can be
selected.

42. Model Selection of Antenna
 Complicated
terrain with
a large fall

43. Model Selection of Antenna
 Areas of a complicated terrain with a large
fall
In the actual networking planning, there may be a
scenario that features a large fall. In that case, Antenna
with 10 to 18 vertical lobe width can be selected
according to the actual situation. In another case, the
area that needs a large coverage is higher than the
mount height of the Antenna. The Antenna with 18 to
30 vertical lobe width can be selected according to the
actual situation.

44. Downtilt Mode of Antenna (1)
 Mechanical downtilt antenna is initially tilted when
installed. The price is low. It is mostly applied in the
scenario with the downtilt angle smaller than 10.
 The price of electrical downtilt antenna is relatively high,
with a larger downtilt range (larger than 10, the antenna
pattern shows no obvious distortion, and the back lobe of
the antenna will also be downtilted at the same time).
 Particularly, the fixed electrical downtilt antenna with a
small angle plus the mechanical downtilt scheme has
advantages in performance and cost.
Antenna downtilt modes include mechanical and electrical downtilt.
Electrical downtilt can be divided into fixed electrical downtilt and
adjustable electrical downtilt.

45. Downtilt Mode of Antenna (2)
 The application of electrical downtilt antenna includes the
following scenarios:
 In city sites with specially small coverage radius, large
downtilt angle is needed to reduce the interference with the
adjacent cells.
 In high sites, to reduce the interference with the adjacent
cells and the problem of “light shadow”, it is better to select
the first upper side lobe suppression and the first null fill-in,
with large-angle electrical downtilt or adjustable electrical
downtilt antenna.
 In sites higher than the surroundings (e.g., mountain top
and riverside), electrical downtilt antenna can be selected.
 Omni antenna cannot be mechanically downtilted. High
omni NodeB should select the electrical downtilt antenna
with different angles according to the different situations.

46. Down tilt angle of Antenna (1)
 In downtown area
: mechanical down tilt ; H: effective height;
L: cell radius;  :Vertical Lobe 3dB Width ;
e: electrical down tilt;
 = arctg(H/L) + /2 – e
α
β/2
α+γe
L
H

47. Down tilt angle of Antenna (2)
α
β/2
α+γe
L
H
 = arctg(H/L) – e
 In rural area
: mechanical down tilt ; H: effective height;
L: cell radius;  :Vertical Lobe 3dB Width ;
e: electrical down tilt;

48. Examples of Antenna (1)
Type: Outdoor omni antenna
Antenna manufacturer: KATHREIN
Model: HXS-201-60-1.9-6-2GHz-60
Work frequency: 1920 MHz ~ 2170MHZ
Gain: 11.6 dBi
Horizontal 3dB beamwidth: 360°
Polarization: Vertical
Angle: 0°
Input impedance: 50 
Dimensions: 60  1500mm
Weight: 3.8kg
Applicable scenario: Suburb and countryside

49. Examples of Antenna (2)
Type: Outdoor directional antenna
Antenna manufacturer: KATHREIN
Model: TDJS-2000-18-H65-3G
Work frequency: 1920 MHz ~ 2170MHZ
Gain: 18dBi
Horizontal 3dB beamwidth: 65
Polarization: 45 polarization
Angle: 0 ~ 15
Input impedance: 50 
Dimensions: 1300mm  160mm  75mm
Weight: 4.5kg
Applicable scenario: High-density downtown
and resident areas

50. Examples of Antenna (3)
Type: Indoor directional antenna
Antenna manufacturer: Mobile Antenna Technologies
(Shenzhen)
Model: MB5F-70/40-9/6-W
Work frequency: 1710 MHz ~ 2170MHZ
Gain: 6 dBi
Horizontal 3dB beamwidth: 40
Polarization: Vertical
Angle: 0
Input impedance: 50 
Dimensions: 240  220  65mm
Weight: 1.5kg
Applicable scenario: Interior of buildings

51. Examples of Antenna (4)
Type: Outdoor Triple Band directional Antenna
manufacturer: Argus
Model: CNNPX303F-P
Work frequency: 824 - 960 / 1710 - 2170 / 1710 - 2170 MHz
Gain: 13dBi
Horizontal beamwidth: 65
Vertical beamwidth: 23° GSM900, 21° UMTS
Electrical Downtilt: 0°~ 10° independently continuously
adjustable
Polarization: 45 polarization
Input impedance: 50 
Dimensions: 860x370x120 mm
Weight: 12kg
Applicable scenario: High-density downtown
and resident areas

52. Examples of Antenna (5)
Type: Outdoor Triple Band directional Antenna
manufacturer: Argus
Model: CNNPX306M-P
Work frequency: 824 - 960 / 1710 - 2170 / 1710 - 2170 MHz
Gain: 16 dBi GSM900, 15.5 dBi GSM1800, 16.5 dBi UMTS
Horizontal beamwidth: 65
Vertical beamwidth: 12° GSM900, 11° UMTS
Electrical Downtilt: 0°~ 10° independently continuously
adjustable
Polarization: 45 polarization
Input impedance: 50 
Dimensions: 1600x370x120 mm
Weight: 21kg
Applicable scenario: High-density downtown
and resident areas

53. Examples of Antenna (6)
Type: Outdoor Dual Band directional Antenna
manufacturer: Argus
Model: CNPX302U
Work frequency: 824 - 960 / 1710 - 2170 MHz
Gain: 9dBi
Horizontal beamwidth: 65
Vertical beamwidth: 38°
Electrical Downtilt: 0°~ 10° independently continuously
adjustable
Polarization: 45 polarization
Input impedance: 50 
Dimensions: 680x200x55 mm
Weight: 2kg
Applicable scenario: High-density downtown
and resident areas

54. Beautified Antenna (1)

55. Beautified Antenna(2)

56. Beautified Antenna(3)
Street lamp Ant
Lawn lamp Ant
VegetableAnt

57. Electrical down tilt Antenna

58. Indoor Antenna

59. Leaky cable