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Transcript of Antenna Basic
Basic Principles For base station Antenna psystems
Antenna TheoryAntenna Theory
By
Amir Miraj, Senior Engineer,
1
Base Station Antenna Technology E l tiEvolution
AntennaCore
Omni Directional
Vertical Polarization
DualPol®MIMO
DualPol®RET
Dual BandCapacity Improvement
DigitalBeam Former
SmartBeam®
Capacity”
Technology
Interference ReductionMIMO
with FrequencyMIMO
SDMACapacity
Load BalanceMIMO
AirInterfaces Dominate Application Significant Application Low Application
AMPS
GSM
CDMA
W-CDMA
WiMAX
TD-SCDMA
LTE
2
LTE
Dipole F0(MHz)
λ(Meters
λ(Inches(MHz) (Meters
)(Inches
)
30 10 0 393 6¼ λ
30 10.0 393.680 3.75 147.6
160 1 87 73 8160 1.87 73.8280 1.07 42.2460 0 65 25 7
F0 ¼ λ460 0.65 25.7800 0.38 14.8960 0.31 12.3
1700 0.18 6.95
3
2000 0.15 5.9
3D View Antenna Pattern
Source: COMSEARCH
4
Source: COMSEARCH
Understanding The Mysterious “dB”g y
dBd Signal strength relative to a dipole in empty space
dBi Signal strength relative to an isotropic radiator
dB Difference between two signal strengths
dBm Absolute signal strength relative to 1 milliwatt1 mWatt = 0 dBm Note: The
Logarithmic Scale1 Watt = 30 dBm20 Watts = 43 dBm
dBc Signal strength relative to a signal of known strength,
Logarithmic Scale10 * log10 (Power Ratio)
in this case: the carrier signalExample: –150 dBc = 150 dB below carrier signalIf two carriers are 20 Watt each = 43 dBm
5
–150 dBc = –107 dBm or ~0.02 pWatt or ~1 microvolt
Effect Of VSWRG d VSWR i l t f ffi i t tGood VSWR is only one component of an efficient antenna.
Return Transmis Power PowerVSWR Loss
(dB)sion
Loss (dB)Reflected
(%)Trans.
(%)1 00 0 00 0 0 100 01.00 ∞ 0.00 0.0 100.01.10 26.4 0.01 0.2 99.81 20 20 8 0 04 0 8 99 21.20 20.8 0.04 0.8 99.21.30 17.7 0.08 1.7 98.31.40 15.6 0.12 2.8 97.21.50 14.0 0.18 4.0 96.0
6
2.00 9.5 0.51 11.1 88.9
Shaping Antenna Patterns
Vertical arrangement of properly phased dipoles allows controlVertical arrangement of properly phased dipoles allows control
of radiation patterns at the horizon as well as above and below
the horizon. The more dipoles that are stacked vertically, the
flatter the vertical pattern is and the higher the antenna
coverage or ‘gain’ is in the general direction of the horizon.
7
aping Antenna Patterns (Continued)
• Stacking 4 dipoles vertically in line changes the pattern shape (squashes the doughnut) and
Aperture of Dipoles
Vertical Pattern
Horizontal Pattern
(squashes the doughnut) and increases the gain over single dipole.
• The peak of the horizontal or
Single Dipole
• The peak of the horizontal or vertical pattern measures the gain.
• The little lobes illustrated in the • The little lobes, illustrated in the lower section, are secondary minor lobes.
• General Stacking Rule
4 Dipoles Vertically Stacked
General Stacking Rule• Collinear elements (in-line vertically).• Optimum spacing (for non-electrical tilt) is approximately 0.9λ.• Doubling the number of elements increases gain by 3 dB, and reduces vertical beamwidth by half.
8
Doubling the number of elements increases gain by 3 dB, and reduces vertical beamwidth by half.
GainGainWhat is it?Antenna gain is a comparison of the power/field characteristics of a device under test (DUT) to a specified gain standardspecified gain standard.
Why is it useful?Gain can be associated with coverage distance and/or obstacle penetration (buildings, foliage, Ga ca be assoc ated t co e age d sta ce a d/o obstac e pe et at o (bu d gs, o age,etc).
How is it measured?It is measured using data collected from antenna range testing. The reference gain standard must always be specified.
Wh i A d d d?What is Andrew standard?Andrew conforms to the industry standard of +/–1 dB accuracy.
9
Gain References (dBd And dBi)
• An isotropic antenna is a single point in space d f Isotropic Pattern
Isotropic (dBi)Dipole (dBd)radiating in a perfect
sphere (not physically possible).
Isotropic Pattern
Dipole Pattern
Dipole (dBd)Gain
dBd
dBi
• A dipole antenna is one radiating element (physically possible).
• A gain antenna is two or more radiating elements phased together. 0 (dBd) = 2.14 (dBi)
3 (dBd) = 5.14 (dBi)
10
Principles Of Antenna GainDirectional Antennas Top ViewOmni Antenna Side View
0 dd B
Directional Antennas, Top ViewOmni Antenna, Side View
0 dd 60°
‐3 dB
+3 ddB180°
0 dd B60
‐3 dB
3 ddB
‐‐3 dB3 dB+3 dd B 30°
‐3 dB
+6 dd B90°
‐‐3 dB3 dB
+6 dd B15°
‐3 dB
+9 dd B45°
‐‐3 dB3 dB
+9 dd B
7.5°
‐3 dB
11
Theoretical Gain Of Antennas (dBd)
3 dB Horizontal Aperture(Influenced by Grounded Back “Plate”)
Typical Lengthof Antenna (ft )
.9λ)
(Influenced by Grounded Back “Plate”) of Antenna (ft.)
360°
180°
120°
105° 90° 60° 45° 33°
800/900 MHz
1800/1900
VerticalBeamwidt
h
diators
ly Spa
ced (0
90 60 45 33 MHz 0 h1 0 3 4 5 6 8 9 10.5 1 0.5 60°
2 3 6 7 8 9 11 12 13.6 2 1 30°
# of Rad
Verticall
3 4.5 7.5 8.5 9.5 10.5
12.5
13.5 15.1 3 1.5 20°
4 6 9 10 11 12 14 15 16.6 4 2 15°
6 7.5 10.5 11.5 12.
513.5
15.5
16.5 18.1 6 3 10°
8 9 12 13 14 15 17 18 19.6 8 4 7.5°
12
8 9 12 13 14 15 17 18 19.6 8 4 7.5Could be horizontal radiator pairs for narrow horizontal apertures.
Antenna Gain
• Gain (dBi) = Directivity (dBi) – Losses (dB)
• Losses: ConductorDielectricImpedancePolarizationPolarization
• Measure using ‘Gain by Comparison’
13
Antenna Polarization• Vertical polarization
– Traditional land mobile use– Omni antennas– Omni antennas– Requires spatial separation for diversity– Still recommended in rural, low multipath environments
• Polarization diversity– Slant 45° (+ and –) is now popular– Requires only a single antenna for diversityq y g y
– Lower zoning impact
– Best performance in high and medium multipath i tenvironments
Measured data will be presented in the Systems Section
14
Various Radiator Designs
800/900 MHz 800/900 MHz 800/900 MHz 800/900 MHz/PCB DualPol®
/DualPol® MAR
(Microstrip Annular Ring)
800/900 MHz DualPol®
/Log PeriodicVertical Pol
1800/1900/UMTSDualPol®
Interleaved Dual Band, DualPol® and MAR
1800/1900/UMTS PCB DualPol®
1800/1900/UMTS Vertical Pol
15
Directed Dipole (Microstrip Annular Ring)
Antenna Basics . . . Cross Polarized Dipoles
Two +/– 45° Polarized Dipoles
Single Vertically Polarized Dipole
16
Feed Harness ConstructionFeed Harness ConstructionASP705KASP705
(Old Style)LBX-6513DS
(Old Style)
Center Feed(Hybrid)
Series Feed CorporateFeed( y )
17
Feed Harness Construction (Continued)
Series Feed Center Feed(Hybrid) Corporate Feed(Hybrid)
Advantages
Minimum feed lossesSi l f d t
Frequency independent main lobe direction
Frequency independent main beam directionSimple feed system lobe direction
Reasonably simple feed system
beam directionMore beam shaping ability, sidelobe system sidelobe suppression
Disadvant Not as versatile as corporate (less
Complex feed system
BEAMTILT
+1°
+2°
ages as corporate (less bandwidth, less beam shaping)
system
450 455 460 465 470 MHz–2°
–1°
0°
+1
ASP‐705
18
Feed Networks
• Coaxial cable
– Best isolation
– Constant impedance
– Constant phase
• Microstripline corporate feeds• Microstripline, corporate feeds
– Dielectric substrate
– Air substrate
19
Microstrip Feed Lines
• Dielectric substrate
– Uses printed circuit technology
– Power limitations
– Dielectric substrate causes loss (~1.0 dB/m at 2 GHz)
Ai b• Air substrate
– Metal strip spaced above a groundplane
– Minimal solder or welded jointsMinimal solder or welded joints
– Laser cut or punched
– Air substrate cause minimal loss (~0.1 dB/m at 2 GHz)
20
Air Microstrip Network
21
LBX‐3316‐VTM Using Hybrid Cable/Air Stripline
22
LBX‐3319‐VTM Using Hybrid Cable/Air Stripline
23
DB812 Omni AntennaV ti l P ttVertical Pattern
24
P tt Si l ti
932DG65T2E‐MPattern Simulation
25
Key Antenna Pattern Objectives
For sector antenna, the key pattern objective is to focus as much energy as possible into a desired sector with a desired radius while minimizing unwanted interference to/from all other sectors.
This requires:
• Optimized pattern shaping
• Pattern consistency over the rated frequency band
• Pattern consistency for polarization diversity models
• Downtilt consistency
26
Main Lobe
What is it?The main lobe is the radiation pattern lobe that contains the majority portion of radiated
35° Total35° TotalMain LobeMain Lobethat contains the majority portion of radiated
energy.
Why is it useful?Shaping of the pattern allows theShaping of the pattern allows the contained coverage necessary for interference‐limited system designs.
How is it measured?How is it measured?The main lobe is characterized using a number of the measurements which will follow.
What is Andrew standard?Andrew conforms to the industry standard.
27
H i t l A d V ti l
Half‐Power Beamwidth
What is it?The angular span between the half‐power (‐3
Horizontal And Vertical1/2 Power1/2 PowerBeamwidthBeamwidth
dB) points measured on the cut of the antenna’s main lobe radiation pattern.
Why is it useful?
30 30
It allows system designers to choose the optimum characteristics for coverage vs. interference requirements.
How is it measured?It is measured using data collected from antenna range testing.
What is Andrew standard?Andrew conforms to the industry standard.
28
Front‐To‐Back RatioWhat is it?The ratio in dB of the maximum directivity of an antenna to its directivity in a specified rearward direction Note that on a dualrearward direction. Note that on a dual‐polarized antenna, it is the sum of co‐pol and cross‐pol patterns.
Why is it useful?yIt characterizes unwanted interference on the backside of the main lobe. The larger the number, the better!
How is it measured?It is measured using data collected from antenna range testing. F/B Ratio @ 180 degreesF/B Ratio @ 180 degreesantenna range testing.
What is Andrew standard?Each data sheet shows specific performance. In general, traditional dipole and patch elements will yield 23–28 dB while the Directed Dipole™ style elements will yield 35–40 dB.
F/B Ratio @ 180 degreesF/B Ratio @ 180 degrees0 dB – 25 dB = 25 dB0 dB – 25 dB = 25 dB
29
y p y y
Sidelobe LevelWhat is it?Sidelobe level is a measure of a particular sidelobe or angular group of sidelobes withgroup of sidelobes with respect to the main lobe.
Why is it useful?Sidelobe level or pattern shaping
Sidelobe LevelSidelobe Level(–20 dB)(–20 dB)
Sidelobe level or pattern shaping allows the minor lobe energy to be tailored to the antenna’s intended use. See Null Fill and Upper Sidelobe SuppressionSidelobe Suppression.
How is it measured?It is always measured with respect to theIt is always measured with respect to the main lobe in dB.
What is Andrew standard?Andrew conforms to the industry standard.
30
y
Null FillingWhat is it?Null filling is an array optimization techniquethat reduces the null between the lo er lobes in the ele ation planelower lobes in the elevation plane.
Why is it useful?For arrays with a narrow vertical beam‐width (less than 12°) null fillingwidth (less than 12 ), null filling significantly improves signal intensity in all coverage targets below the horizon.
How is it measured?Null fill is easiest explained as the relative dB difference between the peakof the main beam and the depth of the 1st lower null.1st lower null.
What is Andrew standard?Most Andrew arrays will have null fill of 20–30 dB without optimization. To qualify as null fill, we expect no less than 15 and typically 10–12 dB!
31
q y , p yp y
I t t F A t With N El ti B idth
Null FillingImportant For Antennas With Narrow Elevation Beamwidths
Null Filled to 16 dB Below Peak
‐40
‐20
0
el (d
Bm)
Transmit Power = 1 W
Base Station Antenna Height = 40 m
B St ti A t G i 16 dBd
100
‐80
‐60
Received
Lev Base Station Antenna Gain = 16 dBd
Elevation Beamwidth = 6.5°
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1‐100
Distance (km)
R
32
Upper Sidelobe Suppression
What is it?Upper sidelobe suppression (USLS) is an array optimization technique that reduces the undesirable
First UpperSidelobeSuppression
sidelobes above the main lobe.
Why is it useful?For arrays with a narrow vertical beamwidth (less than 12°), USLS can significantly reduce interference due to multi‐path or when the antenna is mechanically downtilted.
How is it measured?USLS is the relative dB difference between the peak of the main beam peak of the fi t id l bfirst upper sidelobe.
What is Andrew standard?Most of Andrew’s arrays will have USLS of >15 dB without optimization. The goal of all new designs is to suppress the first upper sidelobe to unity gain or lower
33
designs is to suppress the first upper sidelobe to unity gain or lower.
Orthogonality
What is it?The ability of an antenna to discriminate between two waves whose polarization difference is 90
δ
two waves whose polarization difference is 90 degrees.
Why is it useful?Orthogonal arrays within a single antenna Decorrelation between the Green and Blue Linesallow for polarization diversity. (As opposed to spacial diversity.)
How is it measured?
δ = 0°, XPol = –∞ dBδ = 5°, XPol = –21 dBδ = 10°, XPol = –15 dBδ = 15° XPol = –11 dB
Decorrelation between the Green and Blue Lines
The difference between the co‐polar pattern and the cross‐polar pattern, usually measured in the boresite (the direction of the main signal).
δ = 15 , XPol = 11 dBδ = 20°, XPol = –9 dBδ = 45°, XPol = –3 dBδ = 50°, XPol = –2.3 dBδ = 60° XPol = –1 2 dB
What is Andrew standard?Andrew conforms to the industry standard.
δ = 60 , XPol = 1.2 dBδ =70°, XPol = –0.54 dBδ =80°, XPol = –0.13 dBδ =90°, XPol = 0 dB
XPol = 20 log ( sin (δ))
34
XPol = 20 log ( sin (δ))
120°
Cross‐Pol Ratio (CPR)
-20
-15
-10
-5
0
120What is it?CPR is a comparison of the co‐pol vs. cross‐pol pattern performance of a dual‐polarized antenna generally over the sector of interest (alternatively
-40
-35
-30
-25
Typicalover the 3 dB beamwidth).
Why is it useful?It is a measure of the ability of a cross‐pol array to distinguish between orthogonal waves The better Co‐Polarization
0
120°
distinguish between orthogonal waves. The better the CPR, the better the performance of polarization diversity.
How is it measured?
Co‐Polarization
Cross‐Polarization (Source @ 90°)
-30
-25
-20
-15
-10
-5
Directed
It is measured using data collected from antenna range testing and compares the two plots in dB over the specified angular range. Note: in the rear hemisphere, cross‐pol becomes co‐pol and vice
-40
-35 Dipole™
What is Andrew standard?For traditional dipoles, the minimum is 10 dB; however, for the Directed Dipole™ style elements it increases to 15 dB min
versa.
35
Directed Dipole style elements, it increases to 15 dB min.
Horizontal Beam Tracking
What is it?It refers to the beam tracking between the two beams of a +/–45° polarization diversity antenna 120°120°
p yover a specified angular range.
Why is it useful?For optimum diversity performance, +45°–45°
A Athe beams should track as closely as possible.
How is it measured?I i d i d ll d
Array Array
It is measured using data collected from antenna range testing and compares the two plots in dB over the specified angular range.
What is Andrew standard?The Andrew beam tracking standard is +/–1 dB over the 3 dB horizontal beamwidth.
36
Horizontal
Beam Squint
SquintSquintθ/2
θ
HorizontalBoresiteWhat is it?
The amount of pointing error of a given beam referenced to mechanical boresite.
Wh i it f l? –3 dB +3 dBWhy is it useful?The beam squint can affect the sector coverage if it is not at mechanical boresite. It can also affect the performance of the polarization diversity style antennas if the two arrays do not have similar patterns.
How is it measured?How is it measured?It is measured using data collected from antenna range testing.
What is Andrew standard?What is Andrew standard?For the horizontal beam, squint shall be less than 10% of the 3 dB beamwidth. For the vertical beam, squint shall be less than 15% of the 3 dB beamwidth or 1 degree whichever is greatest
37
1 degree, whichever is greatest.
Sector Power Ratio (SPR)120°120°
What is it?SPR is a ratio expressed in percentage of the power outside the desired sector
120120
pto the power inside the desired sector created by an antenna’s pattern.
Why is it useful?It is a percentage that allows comparison of various antennas. The better the SPR, the better the interference performance of the system.
How is it measured?It is mathematically derived from the measured range data.
300
Desired
Undesired
What is Andrew standard?Andrew Directed Dipole™ style antennas have SPR’s typically less than 2 percent.
PUndesired
SPR (%) = X 100
PDesired
300
60Σ
60
300Σ
38
K A t P t T E i Cl l
Antenna–Based System Improvements
Standard 85° Panel Antenna932LG
Directed Dipole™ Roll off–7 dB –6 dB
Key Antenna Parameters To Examine Closely
Directed Dipoleat ‐/+ 60°
‐10 dBpoints
74° 83°
83°74°
–16 dB –12 dB
HorizontalAnt/AntIsolation
points
Next SectorAnt/AntIsolation–35 dB –18 dB
60°Area of Poor Silence with >27 dB Front‐to‐Back Ratio
120°Cone of Great Silence with >40 dB Front‐to‐Back Ratio
Isolation
Coneof Silence
39
Key Antenna Pattern Objectives
Azimuth Beam
• Beam tracking vs. frequencyLi i d b b d b db d d l
1 1 1Limited to sub‐bands on broadband models
• Squint
• Roll‐off past the 3 dB points
1 1 1
1 2 3
• Front‐to‐back ratio
• Cross‐pol beam tracking
Elevation Beam
1 1 2
1 1 1
Ratings:
1 = Always important
Elevation Beam
• Beam tracking vs. frequency
• Upper sidelobe suppression
1 2 3
1 2 32 = Sometimes important
3 = Seldom important
• Lower null fill
• Cross‐pol beam tracking
3 3 2
2 2 3
40
Key Antenna Pattern Objectives (Continued)
Downtilt
• Electrical vs. mechanical tilt 1 1 3• Absolute tilt
• Electrical tilt vs. frequency
• Effective gain on the horizon
2 2 3
1 2 3• Effective gain on the horizon
Gain
• Close to the theoretical value
1 2 3
2 1 1(directivity minus losses)
Note: Pattern shaping reduces gain. Ratings:
1 = Always important
2 = Sometimes important
3 = Seldom important
41
d i ( )
Advanced Antenna Technology
Adaptive Array (AA)
• Planar array • 4 6 and 8 column vertical pol designs• Planar array
• External digital signal processing (DSP) controls the antenna pattern
• A unique beam tracks each mobile
• 4, 6, and 8 column vertical pol designsfor WiMAX and TD‐SCDMA*
• Often calibration ports are used
A unique beam tracks each mobile
• Adaptive nulling of interfering signals
• Increased signal to interference ratio performance benefits
* Time Division Spatial Code Division Multiple Access
42
MIMO S
Advanced Antenna Technology
MIMO Systems
2 x 2 MIMO Spatial Multiplexing
• Multiple Input Multiple Output • A DualPol® RET for 2x2 MIMO, two p p p p(MIMO)
• External DSP extracts signal from interference
separated for 4x4 MIMO
• Spatial multiplexing works best in a multi‐path environment
• Capacity gains due to multiple antennas
• Space Time Block Coding is a diversity MIMO mode
43
S B ® A F il
Advanced Antenna Technology
SmartBeam® Antenna Family
• Most flexible and efficient antenna system in the industry
• Solution for the traffic peaks instead of raising the bar everywhere• Solution for the traffic peaks instead of raising the bar everywhere
• Full 3‐way remote optimization options- RET – Remote Electrical Tilt (e.g. 0–10°)
RAS Remote Azimuth Steering (+/ 30°)- RAS – Remote Azimuth Steering (+/– 30 )
- RAB – Remote Azimuth Beamwidth (from 35° to 105°)
• Redirect and widen the beam based on traffic requirements
• Balance the traffic per area with the capacity per sector• Balance the traffic per area with the capacity per sector
• Best utilization of radio capacity per sector
• Convenient and low‐cost optimization from a remote office
• Quick and immediate execution
• Scheduled and executed several times a day (e.g. business and residential plan)
44
S B ®
Advanced Antenna Technology
SmartBeam®
3‐Way Model
Azimuth patterns d t
35° 65°measured at 1710–2180 MHz with no radome.
90° 105°
45
S B ®
Advanced Antenna Technology
SmartBeam®
3‐Way Model
Elevation patterns d t
35° 65°measured at 1710–2180 MHz with no radome.
90° 105°
46
System Issues
• Choosing sector antennas
• Narrow beam antenna applications
• Polarization—vertical vs. slant 45°
• Downtilt—electrical vs. mechanical
• RET optimization
• Passive intermodulation (PIM)
• Return loss through coax• Return loss through coax
• Antenna isolation
• Pattern distortion
47
Choosing Sector Antennas
For 3 sector cell sites, what performance differences can be expected from the
use of antennas with different horizontal apertures?p
Criteria
• Area of service indifference between adjacent sectors• Area of service indifference between adjacent sectors (ping‐pong area)
• For comparison, use 6 dB differentials
• Antenna gain and overall sector coverage comparisons
48
120° H i t l O l P tt
3 x 120° Antennas
-5
0
120° Horizontal Overlay Pattern
-25
-20
-15
-10 Examples
Low Band
VPol
-40
-35
-30
25
DB874H120DB878H120
Low Band
4949°°
3 dB
49
90° H i t l O l P tt
3 x 90° Antennas
-5
0
90° Horizontal Overlay Pattern
Examples
-25
-20
-15
-10
DB854DG90 DB842H90
Low Band
XPol VPol
-40
-35
-30
-25DB856DG90 DB844H90DB858DG90 DB848H90LBX‐9012 LBV‐9012LBX‐9013
44°44°
High Band
DB932DG90 UMW‐9015DB950G85
5 dB
DB950G85HBX‐9016UMWD‐09014B UMWD‐09016
50
5 dB
65° H i t l O l P tt Examples
3 x 65° Antennas65° Horizontal Overlay Pattern Examples
CTSDG 06513 DB844H65
Low Band
XPol VPol
-5
0
CTSDG‐06513 DB844H65CTSDG‐06515 DB848H65CTSDG‐06516 LBV‐6513DB854DG65
-25
-20
-15
-10
DB856DG65DB858DG65LBX‐6513LBX‐6516-40
-35
-30
-25
19°19°
High Band
UMWD‐06513 PCS‐06509 UMWD 06516 HBV 6516
10 dB
UMWD‐06516 HBV‐6516 UMWD‐06517 HBV‐6517HBX‐6516HBX‐6517
51
Special Narrow Beam Applications
4‐Sector Site (45°)
6‐Sector Site (33°) RepeaterRoad
Rural Roadway
Narrow Donor, Wide Coverage Antennas
52
Test Drive Route
35
183
CELL SITE
N
53
Polarization Diversity Tests
DB854HV90
DB854DD90DB854DD90
Test A
1 2
DRIVE TESTS +45°/‐45° 0°/90°(Slant 45°) (H/V)
.
Test B
HANDHELD
MOBILE
1A 2A
1B 2B
A
B
( ) ( / )
54
Slant 45° / Hand‐Held In CarS Di it Sl t d +45°/ 45° TEST 1ATEST 1A
Test Set‐Up and Uplink Signal Strength Measurements‐40
EEAA BB
DB854DD90DB833 DB833
G
Space Diversity vs. Slanted +45°/–45°Bm
)
‐50
‐60
9dB9dB
7.5 ft.7.5 ft.
9dB9dB
RedRed BlueBlue
11dB11dB
GreenGreen
BlackBlack
tren
gth (dB
‐70
Signal St
‐80
‐90
moving awayfrom tower
moving towardstower
Vert L f
Vert Ri h
Slant Di
SlantDi
UplinkSi l S h
‐90
‐100moving crossface
55
Left Right Div DivSignal Strength
Slant 45° / Hand‐Held In CarS Di it Sl t d +45°/ 45°
Difference Between Strongest Uplink Signals
TEST 1ATEST 1A
16
Space Diversity vs. Slanted +45°/–45°
8
12
(dB)
0
4
Stren
gth (
Slant ±45°I
‐4
0
Signal Improvement
Difference Between Polarization Diversity and Space DiversityAverage Difference
‐8
56
Slant 45° / Mobile With Glass Mount
S Di it Sl t d +45°/ 45°Test Set‐Up and Uplink Signal Strength Measurements
‐40
EEAA BB
DB854DD90DB833 DB833
TEST 1BTEST 1B
Space Diversity vs. Slanted +45°/–45°Bm
) 11dB11dB
GreenGreen
BlackBlack‐50
9dB9dB
7.5 ft.7.5 ft.
9dB9dB
RedRed BlueBlue
TEST 1BTEST 1B
Strength (d
B
‐60
‐70
moving awayfrom tower
moving towards
Signal S ‐70
‐80
moving towardstower
Vert Vert Slant SlantUplinkSi l St th
‐90moving crossface
57
Left Right Div DivSignal Strength
Slant 45° / Mobile With Glass Mount
S Di it Sl t d +45°/ 45°
Difference Between Strongest Uplink Signals
TEST 1BTEST 1B
16
Space Diversity vs. Slanted +45°/–45°
8
12
(dB)
0
4
l Stren
gth (
‐4
0
Signal
Slant ±45°Degradation
Difference Between Polarization Diversity and Space DiversityAverage Difference
‐8
58
Average Difference
Rysavy Research
59
Future Technology Focus
• Figure 16 shows that HSDPA,1xEV‐DO, and 802.16e are all within 2‐3 dB of the Shannon bound
Shannon’s Law
5
6Shannon boundShannon bound with 3dB marginE V-DOof the Shannon bound,
indicating that from a link layer perspective, there is not much room for improvement ab
le ra
te (b
ps/H
z)
3
4
E V DO802.16HSD PA
Peter Rysavy of Rysavy Research, “Data Capabilities: GPRS to HSDPA and Beyond”, 3G Americas, September 2005
improvement.
• This figure demonstrates that the focus of future technology enhancements h ld b i i
achi
eva
0
1
2
should be on improving system performance aspects that improve and maximize the experienced SNRs in the
t i t d f
The focus of future technology enhancements should be on improving system performance aspects that improve and maximize the experienced SNRs in the system.Peter Rysavy of Rysavy Research, Data Capabilities: GPRS to HSDPA and Beyond, 3G Americas, September 2005
required SNR (dB)-15 -10 -5 00
5 10 15 20
system instead of investigating new air interfaces that attempt to improve the link layer
f
1Peter Rysavy of Rysavy Research, “Data Capabilities: GPRS to HSDPA and Beyond”, 3G Americas, September 2005
60
performance.
L C Ch l I t f /B tt C it A d Q lit
The ImpactLower Co‐Channel Interference/Better Capacity And Quality
In a three sector site, traditional antennas produce a high degree of imperfect power
t l t l
Traditional Flat Panels
control or sector overlap.
Imperfect sectorization presents opportunities for:
• Increased softer hand‐offs
65° 90°
• Interfering signals• Dropped calls• Reduced capacity
The rapid roll‐off of the lower lobes of the Andrew Directed Dipole™ antennas create larger, better defined ‘cones of silence’ behind the array
Andrew Directed Dipole™
65° 90°
behind the array.
• Much smaller softer hand‐off area• Dramatic call quality improvement• 5%–10% capacity enhancement
61
120° Sector Overlay IssuesOn the Capacity and Outage Probability of a CDMA Heirarchial Mobile System with Perfect/Imperfect Power Control and SectorizationBy: Jie ZHOU et, al IEICE TRANS FUNDAMENTALS, VOL.E82‐A, NO.7 JULY 1999
. . . From the numerical results, the user capacities are dramatically decreased as the imperfect power control increases and the overlap between the sectors (imperfect sectorization) increases . . .
Effect of Soft and Softer Handoffs on CDMA System CapacityBy: Chin‐Chun Lee et, al IEEE TRANSACTIONS ON
ntage of
ty loss 10
15
VEHICULAR TECHNOLOGY, VOL. 47, NO. 3, AUGUST 1998
Overlapping angle in degree
Percen
capa
cit
0 5 10 15
5
0
Qualitatively, excessive overlay also reduces capacity of TDMA and GSM systems.
Overlapping angle in degree
62
Hard, Soft, and Softer Handoffs
H d H d ff• Hard Handoff
– Used in time division multiplex systems
– Switches from one frequency to anotherSwitches from one frequency to another
– Often results in a ping‐pong switching effect
• Soft Handoff
– Used in code division multiplex systems
– Incorporates a rake receiver to combine signals from multiple cells
– Smoother communication without the clicks typical in hard handoffshandoffs
• Softer Handoff
– Similar to soft handoff except combines signals from
63
p gmultiple adjacent sectors
Soft and Softer Handoff ExamplesSoft and Softer Handoff Examples
SofterSofter Handoff Two‐Way Soft
HandoffHandoffThree‐Way Soft Handoff
64
Beam Downtilt
In urban areas, service and frequency utilization are frequently improved by
directing maximum radiation power at an area below the horizon.g p
This technique . . .
• Improves coverage of open areas close to the base station• Improves coverage of open areas close to the base station.
• Allows more effective penetration of nearby buildings, particular
high‐traffic lower levels and garages.
• Permits the use of adjacent frequencies in the same general region.
65
Electrical/Mechanical Downtilt
• Mechanical downtilt lowers main beam, raises back lobe.
• Electrical downtilt lowers main beam and lowers back lobeElectrical downtilt lowers main beam and lowers back lobe.
• A combination of equal electrical and mechanical downtilts lowers
main beam and brings back lobe onto the horizon!g
66
Electrical/Mechanical Downtilt (Continued)
Mechanical Electrical
67
DB5083 Downtilt Mounting Kit
DB5083 downtilt mounting kit is
constructed of heavy duty galvanized steel,
designed for pipe mounting
12” to 20” wide panel antennas.
• Correct bracket calibration assumes a plumb mounting pipe!
• Check antenna with a digital level.
68
Mechanical DowntiltPattern Analogy—Rotating A Disk
Mechanical tilt causes . . .
• Beam peak to tilt below horizon
• Back lobe to tilt above horizon
• At ± 90°, no tilt
69
Mechanical Downtilt Coverage
40
50
6070
8090100110
120
130
140 40
50
6070
8090100110
120
130
140
0
10
20
30150
160
170
180 0
10
20
30150
160
170
180
190
200
210 330
340
350 190
200
210 330
340
350
220
230
240250
260 270 280290
300
310
320 220
230
240250
260 270 280290
300
310
320
8°0° 10°6°4°Mechanical Tilt
Elevation Pattern Azimuth Pattern
70
Managing Beam Tilt• For the radiation pattern to show maximum gain in the direction of the horizon, each stacked dipole must be fed from the signal source in phase.
• Feeding vertically arranged dipoles out of phase will generate patterns that look up or g y g p f p g p plook down.
• The degree of beam tilt is a function of the phase shift of one dipole relative to the adjacent dipole.
Dipoles Fed In Phase Dipoles Fed Out of Phase
Generating Beam Tilt
p
Energy
p f
ExciterPhase
in
Exciter
71
P tt A l F i A C O t Of A Di k
Electrical DowntiltPattern Analogy—Forming A Cone Out Of A Disk
Electrical tilt causes . . .
• Beam peak to tilt below horizon
B k l b t tilt b l h i• Back lobe to tilt below horizon
• At ± 90°, tilt below horizon
• All the pattern tilts
Cone of the
All the pattern tilts
Cone of the Beam Peak Pattern
72
Electrical Downtilt Coverage
40
50
6070
8090100110
120
130
140 40
50
6070
8090100110
120
130
140
0
10
20
30150
160
170
180 0
10
20
30150
160
170
180
190
200
210 330
340
350 190
200
210 330
340
350
220
230
240250
260 270 280290
300
310
320
Ele ation Pattern
220
230
240250
260 270 280290
300
310
320
A im th Pattern
8°0° 10°6°4°Electrical Tilt
Elevation Pattern Azimuth Pattern
73
Mechanical Vs. Electrical Downtilt0 10
2030
40
50310
320
330340
350
60
70
80
90270
280
290
300
100
110
120
130230
240
250
260
130
140
150160
170180190200
210
220
230
Mechanical ElectricalMechanical Electrical
74
Effects of Blooming on Sector PerformanceM( )E( ) Tilt Angle Crossover
M0E0 & M0E7 ‐‐‐‐ 17° 10 dB
M7E7 ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 25° 6 dB
M14E0 ‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 29° 4 dB
75
Combined Electrical and Mechanical Tilt
LNX-6512 Blooming (Calc)M0E0 0%
4 Foot Antenna at 780 MHz
M11E0 32.3%
M9E4 34 4%
60%
70%
M0E0 0%M4E0 3.1%M7E0 9.2%M9E0 16.9%M11E0 32.3%M0E4 0%
M7E0 9.2%
M9E0 16.9%
M7E4 18.8% M7E8 36.7%
M9E4 34.4%
M5E8 18 5%
40%
50%
% o
f VB
W) M4E4 6.3%
M7E4 18.8%M9E4 34.4%M0E8 0%M4E8 12.3%
M4E0 3.1%M4E4 6.3%
M4E8 12.3%M4E10 15.4%
M5E10 24.6%
M2E15 16.7%
M3E15 39.4%
M5E8 18.5%
10%
20%
30%
M-ti
lt (% M5E8 18.5%
M7E8 36.7%M0E10 0%M4E10 15.4%M5E10 24.6%M0E15 0%
M0E0 0% M0E8 0%M0E10 0%
M0E4 0% M0E15 0%
M1E15 6.1%
0%0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
E-tilt (% of VBW)
M0E15 0%M1E15 6.1%M2E15 16.7%M3E15 39.4%10% Blooming20% Blooming
76
20% Blooming
Combined Electrical and Mechanical Tilt
LNX-6515 Blooming (Calc)
8 Foot Antenna at 780 MHz
M6E0 40.5% M6E2 78.1%
60%
70%
M0E0 0%M2E0 2.9%M4E0 13.1%
M4E0 13.1%M4E2 25.0%
M4E4 46.9%
30%
40%
50%
(% o
f VB
W) M6E0 40.5%
M8E0 97.3%M0E2 0.0%M2E2 6.3%M4E2 25.0%10% Blooming
M2E0 2.9%M2E2 6.3%
M2E4 10.4%
M1E8 15.6%
M2E8 57.8%
10%
20%
30%
M-ti
lt 10% BloomingM6E2 78.1%M0E4 0.0%M2E4 10.4%M4E4 46.9%M0E8 0.0%
M0E0 0% M0E4 0.0% M0E8 0.0%M0E2 0.0%0%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
E-tilt (% of VBW)
M1E8 15.6%M2E8 57.8%20% Blooming
77
Modified “Rules of Thumb” for 10% Blooming
To insure that the azimuth pattern of a typical antenna ‐ as viewed on the horizon ‐ does not bloom by more than 10%, never mechanically downtilt a given antenna more than the amount calculated by the equations below:amount calculated by the equations below:
65º HBW M‐tilt10% Bloom = (VBW – E‐tilt)/2.5
Other HBW antennas follow different rules:
33º HBW M‐tilt10% Bloom = (VBW – E‐tilt)/1.5
90º HBW M‐tilt10% Bloom = (VBW – E‐tilt)/3.3
78
O ti i ti
Remote Electrical Downtilt (RET)Optimization ATM200‐002
RET Device (Actuator)
Local PC
ATC200 LITE USBATC200‐LITE‐USBPortable Controller
L l PC
ANMS™
Local PC
Network Server
ATC300‐1000Rack Mount Controller
Remote Locations
79
Wh ?
Intermod Interference
R
F1
Tx Rx
F3
Where?
TxF1
RxF3F2
Receiver‐Produced
TxF1
RxF3F2
Transmitter‐Produced
TxF2
TxF2
DUP
F3
F1F2
RxF3
Tx1
F1
F3
Rx3
DUPTx1
Tx2
COMB RF Path‐Produced
3
Tx2
F2 Elsewhere
80
RF Path Produced
P d t F i T Si l IM
High BandProduct Frequencies, Two‐Signal IM
P d t P d t P d t
FIM = nF1 ± mF2Example: F1 = 1945 MHz; F2 = 1930 MHz
1 1 Second 1F1 + 1F2 38751F1 – 1F2 15
Product Product Productn m Order Formulae Frequencies (MHz)
1 2
2 1 Third 2F1 + 1F2 5820*2F1 – 1F2 1960
1 2 Third 2F2 + 1F1 5805*2F 1F 1915*2F2 – 1F1 1915
2 2 Fourth 2F1 + 2F2 77502F1 – 2F2 30
3 2 Fifth 3F1 + 2F2 9695*3F1 – 2F2 1975
2 3 Fifth 3F2 + 2F1 9680*3F2 – 2F1 1900
*Odd d diff d f ll i b d
81
*Odd‐order difference products fall in‐band.
Odd O d Diff P d t
Two‐Signal IMOdd‐Order Difference Products
Example: F1 = 1945 MHz; F2 = 1930 MHz
ΔF = F1 ‐ F2 = 15
F F
ΔF
F21930
F11945
2F1 – F22F2 – F1
dBc
5th
3F2 – 2F11900
F2 F1 3rd
2F1 F21960
5th
3F1 – 2F21975
3rd
2F2 F11915
ΔF ΔFdBm
2ΔF 2ΔF
Third Order: F1 + ΔF; F2 ‐ ΔFFifth Order: F1 + 2ΔF; F2 ‐ 2ΔFSeventh Order: F1 + 3ΔF; F2 ‐ 3ΔFHigher than the highest – lower than the lowest – none in‐between
82
Higher than the highest – lower than the lowest – none in‐between
11th 9th 7th 5th 3rd
PCS A Band Intermodulation11th1855
9th1870
7th1885
5th1900
3rd1915 1930 1945
Channel BandwidthBlock (MHz) FrequenciesC 30 1895–1910 1975–1990
FCC Broadband PCS Band Plan
C 30 1895–1910, 1975–1990C1 15 1902.5–1910, 1982.5–1990C2 15 1895–1902.5, 1975–1982.5C3 10 1895–1900, 1975–1980C4 10 1900–1905, 1980–1985C5 10 1905–1910, 1985–1990
Note: Some of the original C block licenses (originally 30 MHz each) were split into multiple licenses (C‐1 and C‐2: 15 MHz; C‐3, C‐4, and C‐5: 10 MHz).
83
C5 10 1905 1910, 1985 1990
3rd
PCS A & F Band Intermodulation1895 1935 1975
Channel BandwidthBlock (MHz) FrequenciesC 30 1895–1910 1975–1990
FCC Broadband PCS Band Plan
C 30 1895–1910, 1975–1990C1 15 1902.5–1910, 1982.5–1990C2 15 1895–1902.5, 1975–‐1982.5C3 10 1895–1900, 1975–1980C4 10 1900–1905, 1980–1985C5 10 1905–1910, 1985–1990
Note: Some of the original C block licenses (originally 30 MHz each) were split into multiple licenses (C‐1 and C‐2: 15 MHz; C‐3, C‐4, and C‐5: 10 MHz).
84
C5 10 1905 1910, 1985 1990
Causes Of IMD
• Ferromagnetic materials in the current path:Steel– Steel
– Nickel plating or underplating
C di i• Current disruption:– Loosely contacting surfaces
– Non‐conductive oxide layers between contact surfaces
85
System VSWR CalculatorSystem VSWR Calculator
Version 9.0
Frequency (MHz): 850.00 18-Mar-09
System Component Max. VSWR Return Loss (dB)
Cable Type / Component Loss (dB)
Cable Length
(m)
Cable Length (ft)
Ins Loss w/2 Conn
(dB)
% of Est. System
Reflection
Reflections at input
Antenna or Load 1 50 13 98 87 2% 0 1003
Component Used?
Antenna or Load 1.50 13.98 87.2% 0.10032 2 Jumper 1.05 32.26 2 1.83 6.00 0.00 0.0% 0.00002 2 Tower Mounted Amp 1.20 20.83 0.20 0.00 0.0% 0.00002 2 Jumper 1.09 27.32 2 1.83 6.00 0.00 0.0% 0.00002 2 Top Diplexer or Bias Tee 1.15 23.13 0.20 0.00 0.0% 0.00002 2 Jumper 1.09 27.32 2.00 1.83 6.00 0.00 0.0% 0.00002 2 Main Feed Line 1.07 29.42 8 200.00 656.17 0.00 0.0% 0.00002 2 Jumper 1.09 27.32 4 30.48 100.00 0.00 0.0% 0.00002 2 Bi T 1 15 23 13 0 10 11 00 36 09 0 00 0 0% 0 0000
LDF4-50A
VXL7-50 No
No
No
No
No
No
N
No
2 2 Bias Tee 1.15 23.13 0.10 11.00 36.09 0.00 0.0% 0.00002 2 Jumper 1.09 27.32 2.00 1.83 6.00 0.00 0.0% 0.00002 2 Surge Suppressor 1.07 29.42 0.10 0.00 0.0% 0.00002 2 Jumper 1.09 27.32 3.00 1.83 6.00 0.00 0.0% 0.00002 2 Bottom Diplexer or Duplexer 1.20 20.83 0.10 0.00 0.0% 0.00001 1 Jumper 1.08 28.30 1.00 27.30 89.57 3.00 12.8% 0.0385
100.0%
Legacy Jumper / TL Cables Andrew CommScope1/2 i h S fl ibl C FSJ4 50B Estimated Conn Loss ( 2per cable) 0 028
No
No
No
No
YesYes
No
FSJ4-50B
1/2 inch Superflexible Copper FSJ4-50B Estimated Conn Loss ( 2per cable) 0.0281/2 inch Foam Copper LDF4-50A CR 540
1/2 inch Superflexible Aluminum SFX 500 Typical System Reflection: 0.10741/2 inch Foam Aluminum FXL 540 Typical System VSWR: 1.24
Typical System Return Loss (dB): 19.4Legacy Transmission Lines Andrew CommScope
7/8 inch Copper LDF5-50A CR 1070 Worst System Reflection: 0.13871 1/4 inch Copper LDF6-50 CR 1480 Worst System VSWR: 1.321 5/8 inch Copper LDF7-50A CR 1873 Worst System Return Loss (dB): 17.21 5/8 inch Copper LDF7 50A Worst System Return Loss (dB): 17.2
7/8 inch Very Flexible Copper VXL5-501 1/4 inch Very Flexible Copper VXL6-50 Total Insertion Loss (dB): 3.001 5/8 inch Very Flexible Copper VXL7-50
7/8 inch Virtual Air Copper AVA5-50 Return Loss to VSWR converter Feet to meters converterYes 1 5/8 inch Virtual Air Copper AVA7-50
7/8 inch Aluminum AL5-50 FXL 7801 1/4 inch Aluminum FXL 1480 17.00 1.33 100.00 30.481 5/8 inch Aluminum AL7-50 FXL 1873
metersReturn Loss (dB) VSWR Feet
86
No
Possible Cascaded VSWR ResultsPossible Cascaded VSWR ResultsPossible results (at a given frequency) when Antenna and TMA are interconnected withinterconnected with different electrical
length jumpers.If: L = 1.5:1 (14 dB RL Antenna)
S = 1.2:1 (20.8 dB RL TMA)
Then: X (max) = 1.8:1 (10.9 dB RL)
S (min) = 1.25:1 (19.1 dB RL)
Worst case seldom happens in real life, but
b th t it ibe aware that it is possible!
From http://www home agilent com/agilent/editorial jspx?cc=US&lc=eng&ckey=895674&nid=‐35131 0 00&id=895674
87
From http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=895674&nid= 35131.0.00&id=895674
Recommended Antenna/TMA Qualification Test
Antenna
6 foot LDF4‐50A
50 ohm load
6 foot LDF4‐50A
TMA TMAAdapter or jumper to bypass TMA
12 foot LDF4‐50A12 foot LDF4‐50A
TransmissionTransmission Line
20 foot
Transmission Line
20 foot FSJ4‐50
Antenna Return Loss Diagram
20 foot FSJ4‐50
TMA Return Loss Diagram
88
Attenuation Provided By VerticalSeparation Of Dipole Antennas
70
60
50
40
on in
dB
30
20
Isolati
1 2 3 5 10 20 30 50 100(0.3) (0.61) (0.91) (1.52) (3.05) (6.1) (9.14) (15.24)(30.48)
10
Antenna Spacing in Feet (Meters)
The values indicated by these curves are approximate because of coupling which exists between the antenna and transmission line. Curves are based on the use of half‐wave dipole antennas. The curves will also provide acceptable results for gain type antennas. If values (1) the spacing is measured between the physical center of the tower antennas and it (2) one antenna is mounted directly above the other, with no horizontal offset collinear). No correction factor is required f th t i
89
for the antenna gains.
Attenuation Provided By HorizontalSeparation Of Dipole Antennas
80
70
60
50
on in
dB
40
30
Isolati
10 20 30 50 100 200 300 500 1000(3.05) (6.1) (9.14) (15.24) (30.48) (60.96) (91.44) (152.4)(304.8)
20
Antenna Spacing in Feet (Meters)p g ( )
Curves are based on the use of half‐wave dipole antennas. The curves will also provide acceptable results for gain type antennas if (1) the indicated isolation is reduced by the sum of the antenna gains and (2) the spacing between the gain antennas is at least 50 ft. (15.24 m) (approximately the far field).
90
Pattern Distortions
C d i ( lli ) b i i h h fConductive (metallic) obstruction in the path of transmit and/or receive antennas may distort antenna radiation patterns in a way that causes systems coverage problems and degradation of communications services.
A few basic precautions will prevent pattern distortions.
Additional information on metal obstructions can also be found online at: www.akpce.com/page2/page2.html
91
Sid Of B ildi M ti
Pattern DistortionsSide Of Building Mounting
BuildingBuilding
92
Ob t ti @ 10 dB P i t
90° Horizontal PatternObstruction @ –10 dB Point
340330
0 1020
3040320
350
-5
0
880 MHz
7
50
60
0290
300
310
-25
-20
-15
-10
0°
80
90
100260
270
280
-40
-35
-30
25
Antenna
–10 dB Point
BuildingCorner
100
110
120240
250
260
130
140150
160170180190
200210
220
230
93
Ob t ti @ 6 dB P i t
90° Horizontal PatternObstruction @ –6 dB Point
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10 50
60
0290
300
310
0° –6 dB Point-40
-35
-30
25
80
90
100260
270
280
Antenna
BuildingCorner
100
110
120240
250
260
130
140150
160170180190
200210
220
230
94
Ob t ti @ 3 dB P i t
90° Horizontal PatternObstruction @ –3 dB Point
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10 50
60
0290
300
310
0°–3 dB Point
Building-40
-35
-30
25
80
90
100260
270
280
Antenna
BuildingCorner
100
110
120240
250
260
130
140150
160170180190
200210
220
230
95
0 51λ Di Ob l @ 0°
90° Horizontal Pattern0.51λ Diameter Obstacle @ 0°
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10 50
60
0290
300
310
0°
12λ-40
-35
-30
25
80
90
100260
270
280
Antenna
12λ100
110
120240
250
260
130
140150
160170180190
200210
220
230
96
0 51λ Di t Ob t l @ 45°
90° Horizontal Pattern0.51λ Diameter Obstacle @ 45°
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10
5
50
60
0290
300
310
45°-40
-35
-30
25
80
90
100260
270
280
Antenna
8λ100
110
120240
250
260
130
140150
160170180190
200210
220
230
97
0 51λ Di t Ob t l @ 60°
90° Horizontal Pattern0.51λ Diameter Obstacle @ 60°
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10
5
50
60
0290
300
310
60°-40
-35
-30
25
80
90
100260
270
280
Antenna
6λ100
110
120240
250
260
130
140150
160170180190
200210
220
230
Additional information on metal obstructions can also be found online at www akpce com/page2/page2 html
98
www.akpce.com/page2/page2.html.
0 51λ Di t Ob t l @ 80°
90° Horizontal Pattern0.51λ Diameter Obstacle @ 80°
-5
0340
330
0 1020
3040320
350
880 MHz
-25
-20
-15
-10
5
50
60
0290
300
310
-40
-35
-30
25
80
90
100260
270
280
Antenna
3λ80°100
110
120240
250
260
Additional information on metal obstructions can also be found online at www akpce com/page2/page2 html
130
140150
160170180190
200210
220
230
99
www.akpce.com/page2/page2.html.
A Th t N d T B F Of Ob t ti ( 0 51λ)
General RuleArea That Needs To Be Free Of Obstructions (> 0.51λ)
Maximum Gain
3 dB Point(45°)
> 12 WL
(45 )
6 dB Point(60°)( )
10 dB Point> 3 WLWL
Antenna90° horizontal (3 dB) beamwidth
(80– 90°)> 3 WL
100
Pattern Distortions
D
dθ
D
tan θ =
d = D x tan θ
dD
d x tan θtan 1° = 0.01745
for 0° < θ< 10° : tan θ = θ x tan 1°Note: tan 10° = 0 1763 10 x 0 01745 = 0 1745
101
Note: tan 10 = 0.1763 10 x 0.01745 = 0.1745
Gain Points Of A Typical Main Lobe
i lVertical BeamWidth= 2 x θ°θ°
θº
(–3 dB point)θ
Relative to Maximum GainRelative to Maximum Gain
–3 dB point θ° below boresite.–6 dB point 1.35 x θ° below boresite.–10 dB point 1.7x θ° below boresite.
102
Changes In Antenna Performance In The Presence Of:
Non‐Conductive Obstructions
FiberglassPanel
90°
Panel
°PCS A
ntennaaDim “A”
103
Performance Of 90° PCS AntennaBehind Camouflage (¼" Fiberglass)
120° FIBERGLASSPANEL
100°
110°
DIM “A”
90°
perture
80°
1/4 1/4 λλ 1/2 1/2 λλ 1 1 λλ 2 2 λλ11‐‐1/2 1/2 λλ3/4 3/4 λλizon
tal A
p
70°10 2 3 4 5 6 7 8 9 10 11 12
Distance of Camouflage (Inches) (Dim. A)
Hor
104
Performance Of 90° PCS Antenna
Behind Camouflage (¼" Fiberglass)
1 6
1.7
1.5
1.6FIBERGLASSPANEL
DIM “A”
1.4
st Case)
DIM “A”
1.2
1.3
WR (W
ors
1/4 1/4 λλ 1/2 1/2 λλ 1 1 λλ 2 2 λλ11‐‐1/2 1/2 λλ
W/Plain Façade W/Ribbed Façade Without Facade
1.210 2 3 4 5 6 7 8 9 10 11 12
Distance of Camouflage (Inches) (Dim. A)
VS
105
W/Plain Façade W/Ribbed Façade Without Facade
Distance From Fiberglass330°
300° 60°
30°0° 9090°°
330°
300° 60°
30°0° 102102°°
270°
240° 120°
90°
-35-40
-45
-50
-55
270°
240° 120°
90°
30-35-40
-45
-50
-55
210°180°
150°-20-25
-30
No Fiberglass 330°
300°
30°0°
6868°°
210°180°
150°-25
-30
-20
3" to Fiberglass300
270°
60°
90°
-40
-45
-50
240°
210°
180°150°
120°
-20
-25-30
-35
-15
1 5" to Fiberglass
106
1.5 to Fiberglass
Distance From Fiberglass330°
300°
60°
30°0° 112112°°330
°
300° 60°
30°0° 7777°°
270°
240°
120°
-25-30-35
-40
-45
-5090°270°
240°
120°
90°
-25
-30-35
-40
-45
-50
210° 180
°
150°
-20-15
6" to Fiberglass
210°180°
150°-20-15
4" to Fiberglass 330°
300° °
30°
0° 108108°°
300
270°
60°
90°
-40
-45
-50
240°
210° 180
°
150°
120°
-20
-25-30-35
-15
9" to Fiberglass
107
9 to Fiberglass