1. Antennas for CDMA System

2. Contents Base station antenna specification and meanings
Antenna types and trends

3. Technical Data

4. Electrical properties Mechanical properties
Operation Frequency Band
Input impedance
VSWR
Polarization
Gain
Radiation Pattern
Horizontal/Vertical beamwidth
Downtilt
Front/back ratio
Sidelobe suppression and null filling
Power capability
3rd order Intermodulation
Insulation
Mechanical properties
Size
Weight
Robe material
Appearance and color
Working temperature
Storage termperature
Windload
Connector types
Package Size
Lightening

5. Electrical properties

6. Dipoles Wavelength 1/2 Wavelength 1/4 Wavelength 1/2 Wavelength Dipole
1900MHz ：157mm
800MHz ：375mm

7. Multiple dipole matrix
Received power：4 mW
1个 dipole (received power)：1mW
GAIN= 10log(4mW/1mW) = 6dBd

8. Omnidirectional array” Received power：1mW
(Overlook
Antenna
“Sector antenna” Received power：8mW
Gain=10log(8mW/1mW) = 9dBi

9. Frequency Range
CDMA(CELLULA） 800 MHz: MHz
CDMA(PCS/PCN) 1900 MHz: MHz

10. Impedance
50
Antenna
50 ohms
Cable
50 ohms

11. Return Loss： 10log(10/0.5) = 13dB VSWR (Voltage Standing Wave Ratio)
80 ohms
50 ohms
Forwarda: 10W
9.5 W
Backward: 0.5W
Return Loss： 10log(10/0.5) = 13dB
VSWR (Voltage Standing Wave Ratio)

12. 1.5
=(VSWR-1)/(VSWR+1)
RL=-20lg 

13. Polarization
Vertical
Horizontal
- 45degree slant
+ 45degree slant

14. V/H (Vertical/Horizontal)
Slant (+/- 45°)

15. Linear,vertical
dual linear 45 slant

16. Gain
G（、）=4 U（、）/PA unit：dBi
G’= GA/ GA unit：dBd
0dBd=2.15 dBi

17. Ideal radiating dot source
dBd and dBi
2.15dB
Ideal radiating dot source
(lossless radiator)
eg: 0dBd = dBi
Dipole

18. Pattern

19. Beamwidth 3dB Beamwidth 10dB Beamwidth Peak - 3dB Peak - 10dB
60° (eg)
Peak
Peak - 3dB
3dB Beamwidth
120° (eg)
Peak
Peak - 10dB
10dB Beamwidth

20. 3dB Beam width Horizontal
Directional Antenna：65°/90°/105°/120 °Omni：360°

21. 3dB Beam width Vertical
Directional： Omni-directional：

22. Down Tilt
Mechanical down tilt
Fixed electronic down tilt
Adjustable electronic down tilt

23. Demonstration of Electronic Down-tilt

24. Mechanical downtilt
Non down tilt
Electronic downtilt

25. F/B = 10 log(FP/BP) typically ： 25dB
Front to Back Ratio
Ratio of maximum mainlobe to maximum sidelobe
Back power
Front power
F/B = 10 log(FP/BP) typically ： 25dB

26. Upper Side lobes Suppression & Null Fill

27. Sidelobes
DOWN SIDELOBE (dB)
UP SIDELOBE (dB)

30. Permitted Power
Continuous : watts
peak :n2p

31. Isolation
10log(1000mW/1mW) = 30dB
1000mW ( 1W)
1mW

32. Mechanical properties

33. Dimensions
LWH
Length：connected with vertical bandwidth and gain
Width：connected with horizontal bandwidth
Height：connected with techniques adopted

34. Weight
Affecting transmission and deploy

35. Radome Material
PVC, Fiberglass
Anti-temperature、water-proof，anti-aging，weather resistant

36. Colour
Good-looking, environment-protecting

38. Operating Temperature Range
Typical range：-40°C — +70°C

39. Storage Temperature Range
Typically：-40°C — +70°C

40. Wind Load
Eg: 83N at 160 km/h

41. Connector Type
7/16”DIN，N，SMA
female

42. Mast
Mast diameter 45-90mm

43. Lightening Protection
Direct Ground

44. Antenna Systems Antenna systems include more than just antennas
F R D u p l e x r
Comb
-iner
BPF TX RX
Transmission Line
Jumper
Jumpers
Directional
Coupler
Antenna
Antenna systems include more than just antennas
Transmission Lines
necessary to connect transmitting and receiving equipment
Other Components necessary to achieve desired system function
Filters, Combiners, Duplexers - to achieve desired connections
Directional Couplers, wattmeters - for measurement of performance
Manufacturer抯 system may include some or all of these items
remaining items are added individually as needed by system operator

45. Characteristics of Transmission Lines
Physical Characteristics
Type of Line
coaxial, stripline, open-wire
balanced, unbalanced
Physical Configuration
Dielectric:
air
foam
Outside Surface:
unjacketed
jacketed
special: plenum rated
Size (nominal outer diameter)
1/4?1/2? 7/8? 1-1/4? 1-7/8? 2-1/4? 3
Foam
Dielectric
Air
Typical Coaxial Cables
Used as Feeders in Wireless Applications

46. Characteristics of Transmission Lines
Electrical Characteristics
Attenuation:
varies with frequency, size, dielectric characteristics of insulation
usually specified in db/100 ft and/or db/100 m
Characteristic Impedance ZO (50 ohms is the usual commercial standard; 75 sometimes used)
value set by inner/outer diameter ratio and dielectric characteristics of insulation
connectors must preserve constant impedance (see figure at right)
Velocity Factor
determined by dielectric characteristics of insulation.
Power-Handling Capability
varies with size, conductor materials, dielectric characteristics d D
Characteristic Impedance
of a Coaxial Line
Zo = ( 138 / ( 1/2 ) ) Log10 ( D / d )
 = Dielectric Constant
= 1 for vacuum or dry air

47. Mis-Matched Condition for Impedance Transformation
Transmission Lines: Special Electrical Properties
Transmission lines have impedance-transforming properties
When terminated with same impedance as Zo, input to line appears as impedance Zo
When terminated with impedance different from Zo, input to line is a complex function of frequency and line length. Use Smith Chart or formulae to compute
Special case of interest: Line section one-quarter wavelength long has convenient properties useful in matching networks
ZIN = (Zo2)/(ZLOAD)
Zo=50
ZLOAD=
50
ZIN = 50
Matched Condition
Zo=50
ZLOAD= 83
-j22
ZIN = ?
Mis-Matched Condition
Zo=50
ZLOAD=
100
ZIN=25
/4
ZIN= ZO2/ ZLOAD
Deliberate Mis-Match
for Impedance Transformation

48. Transmission Lines: Some Practical Considerations
Foam
Dielectric
Air
Transmission Lines: Some Practical Considerations
Periodicity of inner conductor supporting structure can cause VSWR peaks at some frequencies, so specify the frequency band when ordering
Air dielectric lines:
lower loss than foam-dielectric; dry air is excellent insulator
shipped pressurized; do not accept delivery if pressure leak
Foam dielectric lines
simple, low maintenance; despite slightly higher loss
small pinholes and leaks can allow water penetration and gradual attenuation increases

49. MAIN FEEDER

50. JUMP CABLE

51. 7DIN CONNECTOR
DIN & N CONNECTOR

52. Lightening Arrestor
Rf port 2
Grounding

53. ACCESSORIES Trimming Tool or Hand Tool Kit Clamp Earthing Kit
Wall Glands
Hoisting Stocking
Universal Ground Bar

54. 1/2 Clamp Grounding bar Antenna 7/16 Din Connector 1/2 Jumper
Tower Top Amplifier
7/8“ Cable
7/8“ Cable
Grounding
Machine house
1/2“ Jumper
Grounding clip
EMP
Grounding bar
Cabinet

55. Transmission Lines: Important Installation Practices
Respect specified minimum bending radius!
Inner conductor must remain concentric, otherwise Zo changes
Dents, kinks in outer conductor change Zo
Don抰 bend large, stiff lines (1-5/8?or larger) to make direct connection with antennas. Use appropriate jumpers, weatherproofed properly. Secure jumpers against wind vibration.
Observe
Minimum
Bending
Radius!

56. Transmission Lines: Important Installation Practices
During hoisting, allow line to support its own weight only for distances approved by manufacturer. Deformation and stretching may result, changing the Zo. Use hoisting grips, messenger cable
After mounting, support the line with proper mounting clamps at manufacturer抯 recommended spacing intervals. Otherwise, strong winds will set up damaging metal-fatigue-inducing vibrations
200 ft
~60 M
Max.
3-6 ft

57. Typical RF Bandass Filter
RF Filters: Types and Applications
Filters are the basic building blocks of duplexers and more complex devices
Most manufacturers network equipment includes internal bandpass filters at receiver input and transmitter output
Filters are also available for special applications
number of poles (filter elements) and other design variables determine filter抯 electrical characteristics
bandwidth, rejection, insertion loss, slopes, losses, ripple, etc.
Notice construction: RF input excites one quarter-wave element and electromagnet fields propagate from element to element, finally exciting the last element which is directly coupled to the output.
Each element is individually set and forms a pole in the filter抯 overall response curve.
Typical RF Bandass Filter
/4

58. Typical RF Bandass Filter
RF Filters: Basic Characteristics & Specifications
Typical bandpass filters have insertion loss of 1-3 dB. and passband ripple of 2-6 dB.
Bandwidth is typically 1-20% of center frequency, depending on application. Attenuation slope and out-of-band attenuation depend on # of poles & design
Typical RF Bandass Filter
Attenuation, dB
Frequency, MegaHertz
passband ripple
insertion
loss
-3 dB
passband
width
Types of Filters
Single-Pole:
Pass
Reject (notch)
Multi-pole:
Band-Pass
Band-Reject
Key Electrical Characteristics
insertion loss
passband ripple
passband width
upper, lower cutof f frequencies
attenuation slope at band edge
ultimate out-of-band attenuation

59. Typical Tuned Combiner Application
Basics of Transmitting Combiners
Typical Tuned Combiner Application
Purpose: Allow multiple transmitters to feed single antenna, and provide:
minimum loss from transmitter to antenna
maximum isolation between transmitters
Types:
Tuned
low insertion loss ~1-3 dB
transmitter frequencies must be significantly separated
Hybrid
insertion loss -3 dB per stage
no restriction on transmitter frequencies
Linear Amplifier
linearity and intermodulation are major design & operation issues TX
Antenna
Typical Hybrid Combiner Application TX
Antenna
~-3 db

60. One Operator抯 CDMA Carriers Linear Amplifier Method
Combiners: CDMA Considerations
CDMA operators will want to combine multiple CDMA carriers into single antennas; combiners will be needed
Tuned Combiner Technique
must use multi-pole bandpass filters
adjacent-frequency CDMA carriers probably cannot be combined using this technique alone
Hybrid Technique
substantial insertion loss will limit number of carriers per antenna to perhaps 4 if technique used alone
Composite method using staggered tuned combiners and hybrid combiners, and/or
Linear amplifiers will probably be exploited for high-density CDMA BTS configurations in the future
Composite Method:
Tuned & Hybrid f4 f6 f5 f1 f7 f3 f8 f2
Hybrid Combiner
One Operator抯 CDMA Carriers
Antenna
Linear Amplifier Method
Linear Amplifier

61. Principle of Operation
Duplexer Basics
Duplexer Purpose: allow simultaneous transmitting and receiving on one antenna
Zte 1900 MHz BTS RFFEs include internal duplexer
Zte 800 MHz. BTS does not include duplexer but commercial units can be used if desired
Important Duplexer Specifications
TX pass-through insertion loss
RX pass-through insertion loss
TX-to-RX isolation at TX freq. (RX intermodulation issue)
TX-to-RX isolation at RX freq. (TX noise floor issue)
internally-generated intermod limit specification fR fT RX TX
Antenna
Duplexer
Principle of Operation
Duplexer is composed of individual
bandpass filters to isolate TX from
RX while allowing access to antenna
for both. Filter design determines
actual isolation between TX and RX,
and insertion loss TX-to-Antenna
and RX-to-Antenna.

62. Typical Directional Coupler Principle of Operation
Directional Couplers
This device measures forward and reflected energy in a transmission line. It has 4 ports:
Input (from TX), Output (to load)
Forward, Reverse Samples
Sensing loops probe E& I in line
equal sensistivity to E & H fields
terminations absorb induced current in one direction, leaving only sample of other direction
Typical Performance Specs:
Coupling factor ~20, ~30, ~40 db., order as appropriate for application
Directivity ~30-~40 dB., f($)
defined as relative attenuation of unwanted direction in each sample
Typical Directional Coupler
Principle of Operation
ZLOAD=
50
Input
Reverse Sample
Forward Sample RT
Main line E & I induce equal signals in
sense loops. E is direction-independent,
but the polarity depends on direction and
cancels sample induced in one direction.
Thus sense loop signals are directional.
One end is used, the other terminated.

63. Return Loss and VSWR Measurement
Transmission
Line
Antenna
Directional
Coupler
Fwd
Refl RF
Power
A perfect antenna will absorb and radiate all the power fed to it.
Real antennas absorb most of the power, but reflect a portion back down the line.
A Directional Coupler or Directional Wattmeter can be used to measure the magnitude of the energy in both forward and reflected directions.
Antenna specs give maximum reflection over a specific frequency range.
Reflection magnitude can be expressed in the forms VSWR, Return Loss, or reflection coefficient.
VSWR = Voltage Standing Wave Ratio

64. Return Loss and VSWR Calculations
Forward Power, Reflected Power, Return Loss, and VSWR are related by the following equations and the graph.
Typical antenna VSWR specifications are 1.5:1 maximum over a specified band.
VSWR 1.5 : 1
= 14 db return loss
= 4.0% reflected power
VSWR vs. Return Loss
VSWR 10 20 30 40 50 1
1.5 2
2.5 3
VSWR =
Reflected Power
Forward Power
1 +
1 -
Reflected Power
Forward Power
Return
Loss, dB
= 10 x Log10 ( )

65. Thank you