1.
October 2013 | |Wayne Turner ,Sukhvinder Malik, Rahul
Atri , Preet Kanwar Rekhi
White Paper
Fundametals of Cellular
Antenna : Creating
Magic in Air
1. Introduction
In our daily life we see so many antennas everywhere, from simple
radio transreceiver to big tower antennas and DTH antennas. Antenna
is a magical element in the field of communication. Nobody can dream
of wireless communication without the use of antennas. It’s the antenna
which creates the magic in the air and makes wireless communication
possible.
In this paper authors will discuss about the cellular antennas. They will
concentrate mainly on fundamentals of antenna, relationship between
frequency, wavelength and dipole wave propagation and parameters of
antenna like Gain, VSWR, SFR and FBR etc.
Authors also discuss about types of down tilt, generic requirements of
antennas, selection of antennas and beam forming and active antenna
systems.
2. What is an antenna
An antenna is an electrical device which converts electric
power into radio waves, and vice versa. It is usually used with a radio
transmitter or radio receiver.
An antenna is the converter between two kinds of electromagnetic
waves: cable bounded wave’s ⇔ free space wave
Contents
1. Introduction
2. What is an antenna
3. Relation
Between
Wavelength,
Frequency
and Dipole Length
4. Electric and Magnetic
Field on Dipole
5. Wave propagation
6. Antenna Polarization
7. Antenna
Radiation
pattern
8. Antenna
Gain and
Antenna Beam Calculation
9. VSWR for an Antenna
10. Other
Antenna
Parameters
11. Mechanical
and
Electrical Down Tilt
12. Antenna
Generic
Requirement
13. Antenna
Integration
with the base station
with generations
14. References

2.
An antenna consists of an arrangement of metallic conductor
("elements"), electrically connected (often through a transmission line)
to the receiver or transmitter. An oscillating current of electrons forced
through the antenna by a transmitter will create an oscillating magnetic
field around the antenna elements, while the charge of the electrons
also creates an oscillating electric field along the elements.
These time-varying fields, when created in the proper proportions,
radiate away from the antenna into space as a moving transverse
electromagnetic field wave. Conversely, during reception, the
oscillating electric and magnetic fields of an incoming radio wave exert
force on the electrons in the antenna elements, causing them to move
back and forth, creating oscillating currents in the antenna.
Antennas may also include reflective or directive elements or surfaces
not connected to the transmitter or receiver, such as parasitic
elements, parabolic reflectors or horns, which serve to direct the radio
waves into a beam or other desired radiation pattern.
Antenna



Antennas can be designed to transmit or receive radio waves in all
directions equally (omnidirectional antennas), or transmit them in a
beam in a particular direction, and receive from that one direction only
Antenna Consist of
metallic conductor
Antennas are designed
to transmite or receive
the wave
Antenna is a quad pole
device like amplifier
and filter
All RF components can be classified into two types:


Dual-pole (one termination) example for a dual-pole device: 50
ohm load
Quad pole (two terminations) devices examples for a quadpole device: amplifier, filter.
The antenna is a quad-pole device with the second termination
connected to free space waves.

3.
3. Relation B/w Wavelength, Frequency and Dipole
Length
The length of antenna dipole is dependent on frequency of operation.
Frequency and dipole length are inversely proportional, if the frequency
is low then length of antenna will be high and if frequency is high the
length of dipole antenna is less.
Below figure shows the relationship between antenna and frequency
Relation between frequency and wave length: λ = C/ f
λ (m) = 300/ f [MHz]
Example: f =935 MHz ⇒ λ = 0.32 m ⇒ dipole length (λ /2) ~160 mm
f =1800 MHz ⇒ λ = 0.167 m ⇒ dipole length (λ /2) ~ 83 mm
f =2100 MHz ⇒ λ = 0.142 m ⇒ dipole length (λ /2) ~ 71 mm
f =2300 MHz ⇒ λ = 0.130 m ⇒ dipole length (λ /2) ~ 65 mm
Both 900 MHz and 1800 MHz band are used by GSM technology, 2100
MHz is used by UMTS 3G technology and 2300 MHz is used for
Broadband Wireless Access (BWA) technology like WiMAX and LTE.
From above examples, we can see that as the frequency is increasing the
length of dipole is decreasing
4. Electric and Magnetic Field on Dipole
As we know that Antenna converts electrical energy into
electromagnetic energy. When this electrical signal is applied the dipole
antenna maximum voltage appears between the ends of the dipole, the
voltage results in the electrical field (E) lines which occurs between
these two charge centres.
The current on the dipole causes a magnetically field (H) with an
opposite amplitude distribution (max. at the feeding point, min. at the
dipole ends)
Wavelength, Frequency
and Dipole





Wavelength λ (m) =
300/ f [MHz]
Dipole Length= λ /2
As the frequency is
increasing the length of
dipole is decreasing
voltage results in the
electrical field (E)
Current on the dipole
causes a magnetically
field (H)

4.
5. Wave propagation
Wave propagation is any of the ways in which waves travel.
For electromagnetic waves, propagation may occur in a vacuum as
well as in a material medium. Other wave types cannot propagate
through a vacuum and need a transmission medium to exist.
The electrical signal converted into electromagnetic wave and
transmitted over air. The wave now propagates in the air by
conversion from electrical to magnetic energy and vice versa as
shown in below figure.
Wave Propagation and
Antenna Polarization


The wave now propagates
in the air by conversion
from electrical to magnetic
energy and vice versa
The polarization of an
antenna is the orientation
of the electric field (Eplane) of the radio wave
with respect to the Earth's
surface
6. Antenna Polarization
The polarization of an antenna is the orientation of the electric field (Eplane) of the radio wave with respect to the Earth's surface and is
determined by the physical structure of the antenna and by its orientation.
There are different type of polarization of antenna and most common
polarization and dipole orientation of dipole is given below:



4
Dipole orientation vertical :
Vertical polarization ⇒ mainly used for mobile communication
Dipole orientation Horizontal :
Horizontal polarization ⇒ mainly used for broadcasting
Dipole orientation +/-45° slanted :
Cross polarization ⇒ used for polarization diversity with digital
cellular networks

5.
7. Antenna Radiation pattern
The radiation pattern of an antenna is a plot of the relative field
strength of the radio waves emitted by the antenna at different
angles. It is typically represented by a three dimensional graph, or
polar plots of the horizontal and vertical cross sections.
Antennas 3-dimensional pattern can be described by a vertical and
horizontal cut
 Vertical polarization :
Horizontal pattern = H-plane (magnetic field)
Vertical pattern = E-plane (electric field)
 Half power beam width opening angle of the beam
determined by the half power points (reduction by 3 dB)
Aa
Antenna Radiation Pattern
 Antenna Have a 3 dimensional
Pattern
- Horizontal Pattern
- Vertical Pattern
- Half power beam width
The pattern of an ideal isotropic antenna, which radiates equally in
all directions, would look like a sphere. Many non - directional
antennas, such as monopoles and dipoles, emit equal power in all
horizontal directions, with the power dropping off at higher and
lower angles; this is called an omnidirectional pattern and when
plotted looks like a torus or donut.
The radiation of many antennas shows a pattern of maxima or
"lobes" at various angles, separated by "nulls", angles where the
radiation falls to zero. This is because the radio waves emitted by
different parts of the antenna typically interfere, causing maxima at
angles where the radio waves arrive at distant points in phase, and
zero radiation at other angles where the radio waves arrive out of
phase. In a directional antenna designed to project radio waves in a
particular direction, the lobe in that direction is designed larger
than the others and is called the "main lobe". The other lobes
usually represent unwanted radiation and are called "side lobes".
The axis through the main lobe is called the "principal axis" or
"bore sight axis".

6.
8. Antenna Gain and Antenna Beam Calculation
Gain is a parameter which measures the degree of directivity of the
antenna's radiation pattern. A high-gain antenna will preferentially
radiate in a particular direction.
The gain of an antenna is a passive phenomenon - power is not added
by the antenna, but simply redistributed to provide more radiated
power in a certain direction than would be transmitted by an isotropic
antenna. The gain is measured in dBi and dBd
dBi is gain with reference to Isotropic Antenna
dBd is gain with reference to Dipole Antenna
In practice, the half-wave dipole is taken as a reference instead of the
isotropic radiator. The gain is then given in dBd (decibels
over dipole):
There is a relation between dBd and dBi given below
Antenna Gain
dBi= dBd + 2.15
.
The gain is measured in dBi
and dBd

dBi is gain with
reference to Isotropic
Antenna
 dBd is gain with
reference to Dipole
Antenna
The relation between dBd
and dBi
dBi= dBd + 2.15
An antenna designer must take into account the application for the
antenna when determining the gain.


High-gain antennas have the advantage of longer range and
better signal quality, but must be aimed carefully in a
particular direction.
Low-gain antennas have shorter range, but the orientation of
the antenna is relatively inconsequential.
Antenna Gain and Dipole Arrangement:
To concentrate the radiated power into the area around the horizon,
half wave dipoles are arranged vertically and combined in phase
With every doubling of the dipoles number


The half power beam width approx. halves
The gain increases by 3 dB in the main direction

7.
Following figure show the vertical arrangement of dipole
beam width and respective gain
Aa
Accordingly also in the horizontal plane a beam can be
created with each halving of the beam width the gain is
increased by 3 dB (the shown patterns are theoretically)
The resulting gain of an antenna is the sum of the “vertical” and
“horizontal” gain

8.
Calculation of the Gain and Beam width for an antenna:
An Antenna is in below figure in which dipoles are arranged in
vertical polarization. Following are the step to calculate the gain
of antenna. The shown Antenna has 8 Dipole in vertical direction
which contributes 9dB. 3 dB due to Back plane of antenna and
further 3 dB to one more column of 8 dipole in Horizontal plane.
9 dB gain due to 8 no of dipoles in vertical direction
3 dB gain due to Backplane
3 dB gain due to addition of one more column of eight dipoles in
horizontal plane
Total gain =9 +3 +3 = 15 dB with reference to dipole antenna
Now if we want to convert it with reference to the Isotropic
antenna then we have to add 2.15 dB in gain of dipole
Then gain of antenna in dBi = 15 +2.15dB =17.15 dB
In the same manner we can find out the beam width of antenna.
A dipole have 78 Degree beam in vertical plane and doubling the
dipole makes beam width half. For 2 Dipole in vertical make
vertical beam width to 32 Degree and further 8 Dipole make
beam width as 7 degree. Some of the beam power is wasted in
the minor lobe while designing the antenna.
Same with Horizontal beam width, the two columns make
horizontal beam width as 90 degree.
Then the specification of such antenna becomes as below:
8
Horizontal beam width = 90 Degree
Vertical beam Width = 7 Degree
Gain of antenna = 17.15 dBi

9.
9. VSWR for an Antenna
For a radio transmitter or receiver to deliver power to
an antenna, the impedance of the radio and transmission line
must be well matched to the antenna's impedance. The
parameter VSWR is a measure that numerically describes
how well the antenna is impedance matched to the radio or
transmission line it is connected to.
The Antennas are screened (pass/fail criteria) based on
VSWR specifications (VSWR specs).
For VSWR Example we can assume a generator will generate
a frequency and send it to a termination. The termination may
not accept the entire input power (green line), and therefore
will reflect some of the input power (red line) back to the
generator.
VSWR


The forward running signal together with the return running
signal create a standing wave (VSWR = voltage standing
wave ratio)


VSWR (s) = U max. / U min. (range 1 to ∞)
Return loss attenuation:Rerun Loss [dB] = − {20 log*Ur − 20 log*Uv}
The forward running
signal together with the
return running signal
create a standing wave
VSWR (s) = U max. /
U min. (range 1 to ∞)
Return loss attenuation
Rerun Loss [dB] = −
{20 log*Ur − 20
log*Uv}
Standard values for
mobile communication
networks
• VSWR < 1.5
• Return loss <
14 dB

10.




Standard values for mobile communication networks
VSWR < 1.5
Return loss < 14 dB
Mismatch loss :The loss which is effecting the system
performance due to the reflected/returned power
VSWR
1.5
1.3
1.2
Mismatch loss (dB) 0.18 0.08
0.04
For an optimized system performance, all components
have to be matched and Professional applications use a
nominal impedance of 50 Ohms
Exact value only for one frequency; over the operating
band deviations from 50 Ohms are specified by the
VSWR
Other Antenna Parameters





There are some other
important parameters
of antenna like Beam
Squint, Sector Power
Ratio and Front to
Back Ratio
Beam squint is defined
as the difference
between the
mechanical bore site
and the electrical bore
site of an antenna.
Sector Power Ratio
(SPR) is another
measure of an
antenna’s ability to
minimize interference
FBR is the ratio of
Max. Directivity of an
antenna to its
directivity in opposite
direction
Cross polarization ratio
is a difference in dB
between the peak of the
co-polarized main
beam and the max.
10. Other Antenna Parameters
There are some other important parameters of antenna like
Beam Squint, Sector Power Ratio and Front to Back Ratio
(F/B). We will discuss about them in brief and significance of
the parameters.
Beam Squint
 Beam squint is defined as the difference between the
mechanical bore site and the electrical bore site of an
antenna.
 The mechanical bore site is defined as being
perpendicular to the antenna’s back tray
 Electrical bore site is defined as the mid-point of the 3
dB beam width.

11.
This figure shows the example of ”Beam Squint” . As per
specification requirement the beam squint should be minimum.
Sector Power Ratio
 Sector Power Ratio (SPR) is another measure of an
antenna’s ability to minimize interference.
 SPR compares the RF power radiated outside the sector to
the RF power radiated and retained within the sector. It is
expressed in percentage and SPRs as low 3% – 4%,

12.
Front to Back Ratio (F/B)
 FBR is the ratio of Max. Directivity of an antenna to its
directivity in opposite direction.
 Ratio of signal strength transmitted in a forward direction to
that transmitted in a backward direction
 A front-to-back ratio is usually expressed in dB
 FBR of antenna‘s ability to generate or neglect the
interference through its back lobe.
 Front-to-back ratio (F/B) compares gain at bore site to gain
at point 180º behind bore site
 It is often expressed as the F/B ratio over some angle around
the 180º point (ie. 180 ±30º)
Cross Polarization Ratio (CPR)
 Cross polarization ratio is a difference in dB between the
peak of the co-polarized main beam and the max. Cross
polarized signal over an angle measured with in defined
region.
 Cross-Polarization Ratio (CPR) is a measure of the decorrelation of the two polarizations used in a X-Pol antenna
one at +45º and the other at – 45º.
 The better the CPR, better the performance of the
polarization Diversity.

13.
11. Mechanical and Electrical Down Tilt
In any Radio network Following are the possible solutions to reduce
the coverage to mitigate the unwanted interference:
•
•
•
•
Lowering the Antenna height
Replacing the Antenna with lower gain of Antenna
Down tilting the elevation beam
Down-tilting of elevation beam is the most cost effective and
predominantly used techniques even in 2G (GSM/CDMA)
technologies.
There are two types of Down Tilts are possible:
•
•
Electrical: By changing the phase in the individual
antenna dipoles
- Fixed Tilt
- Mechanical Electrical Tilt (MET)
- Remote electrical Tilt (RET)
Mechanical Tilt: Simply tilting the Antenna
mechanically
Mechanical Downtilt
 A mechanical down tilt increases the upper distance to the mast
and makes the antenna pointing down
 The requested down tilt angle is achieved only in main
direction
 Effective down tilt varies across the azimuth
Mechanical Downtilt (Effect on Horizontal Pattern)
 Effect on the horizontal pattern at the horizon : reduction of the
field strength in main direction without any change +/- 90° to it
results in deformation of the horizontal pattern
 This effect of changing half power beam width can hardly be
considered in the network planning and reduces the prediction
accuracy.
Mechanical and Electrical
Down Tilt
Two Types of tilt
• Electrical: By changing
the phase in the
individual antenna
dipoles
- Fixed Tilt
- Mechanical Electrical Tilt
(MET)
- Remote electrical Tilt
(RET)
• Mechanical Tilt: Simply
tilting the Antenna
mechanically

14.
Mechanical Down lint and its impact on antenna Pattern
Each colour shows the different angle of mechanical downtilt. We can
see for 10 degree downtilt antenna horizontal pattern total shrink
Electrical Downtilt
More elegant in the electrical down tilt with the antenna remaining
upright; instead of equal phases on the dipoles, particular phase
distributions are selected by varying the cable lengths to the dipoles.
In Electrical Downtilt the following is done :



The fixed phase distribution applies to all azimuth directions ⇒
electrical down tilt angle is constant
The shape of the horizontal pattern remains constant
Accurate network planning is assured

15.
If we closely see both the down tilting we will find that electrical down
tilting is more uniform than the mechanical down tilt. Electrical down
tilt equally attenuate the pattern in on the directions by controlling the
feed current while in mechanical downtilt basically tilt attenuate the
main 0 degree attenuation beam by physically down tilting the antenna
which further increase the SPR (Sector Power ratio)
The Electrical downtilt have following flavours
 Fixed Electrical Tilt (for e.g., 0°, 2°, 4° etc. ):
 Mechanical Electrical Tilt (MET):
- Electrical tilt of antenna can be change by just changing
the knob mechanically
- It can change the tilt in some degree (1 or 2°) of steps.

Remote Electrical Tilt (RET):
- Electrical tilt can be controlled remotely through
EMS/NMS of a network.
- This is a great feature as RF optimizations can be done
without physically going to the cell site.
Electrical Tilt vs. Mechanical Tilt
• Small value of mechanical tilt, the pattern seems acceptable but
with greater amount of down tilt, the pattern takes on a
“peanut” Shaped look. This is undesirable as the purpose of
down tilting is to reduce the coverage in all directions to reduce
the interference.

16.
• Even though the mechanical tilted antenna’s horizontal pattern cut
look acceptable at smaller value of tilt, a subtle difference is
taking place ----commonly referred to as ‘pattern booming’. In
essence 3 dB beam width getting larger. Hence it increases the
sector overlap area.
• In the case of electrical tilt, the Gain is reduced in all directions.
Sector overlap area will not increase. Therefore electrical tilt
is always better solution than the mechanical tilt.
• In the past, the thumb rule for maximum mechanical tilt was = ½ of
the vertical beam width of Antenna. This cannot be used where
the electrical tilt of Antenna is also used.
Antenna generic Requirement
Interface requirements are:
 Antenna should have 50
ohm RF interface for
prefect impedance
matching
 Antenna should have
RF interface of 7/16
DIN Type connector
 It should be bottom fed
type to ease access
 It should have AISG
interface for RFT
feature for remote
electrical tilt
Electrical requirements are:
 Operating Frequency,
Peak Power support,
VSWR, Polarization,
FBR, SPR, Efficiency,
RET capability, HBW,
VBW and Gain related
requirements can be
considered under
electrical requirement.
Environmental requirement
 Operating Temp.
Range, Humidity
Range, IP65 for dust
and water protection,
survive wind loading
speed, Mechanical
strength and resistance
to Corrosion can be
considered under
Environmental
requirements
12. Antenna Generic Requirement
When we are selecting an antenna have to make some generic
requirements. Broadly these requirements are related to Interface,
Electrical requirement and Environmental requirement
Interface requirements are:
 Antenna should have 50 ohm RF interface for prefect
impedance matching
 Antenna should have RF interface of 7/16 DIN Type connector
 It should be bottom fed type to ease access
 It should have AISG interface for RFT feature for remote
electrical tilt
Electrical requirements are:
 Operating Frequency, Peak Power support, VSWR,
Polarization, FBR, SPR, Efficiency, RET capability, HBW,
VBW and Gain related requirements can be considered under
electrical requirement.
Environmental requirement
 Operating Temp. Range, Humidity Range, IP65 for dust and
water protection, survive wind loading speed, Mechanical
strength and resistance to Corrosion can be considered under
Environmental requirements
13. Selection of antenna

17.
Choice of Omni Antenna




Omni-Antenna: 360 degree beam width in horizontal plane
Gain of the antenna is only depends upon the vertical beam
width. Direct trade-off between Gain and vertical beam width
For 7° vertical beam width, gain of the antenna will be 9 dB
(due to 8 vertical elements) + 2.15 dB (dipole gain)= ~ 11 dBi
Application:
- In Rural Area where capacity of a BTS is not required
- For in building coverage with Pico and femto BTS.
Choice of Sectored Antenna
Sectored Antenna: (Directional Antenna)
Will have directivity in horizontal and vertical plane both,
Antenna gain is depends on horizontal & vertical beam width as
beam width decreases, Gain increases and vice a versa.
Horizontal (Azimuth) beam width of Antenna requirement
comes from the number of sectors in the bases station and
deployment scenario. Vertical beam width requirement comes
from the antenna placement height. For e.g. Antenna on 30
meter tower height required 7° vertical beam width.
 Following sectored Antenna are generally available:
 45° Horizontal Beam width
 65° Horizontal Beam width
 90° Horizontal Beam width
 120° horizontal Beam width
45°Horizontal Beam width Antenna:
Used for 4 sectors Base Station, Very less usage of such antenna
because of more overlap area for 4 sector BTS configuration
65°Horizontal Beam width Antenna:
Used for 3 sectors Base Station especially in Dense Urban,
Urban & Sub-urban, Widely used Antenna. ~ 75% of total
antennas are used of this type in any network.
90° Horizontal Beam width Antenna:
Used for 3 sector Base Station especially in rural area
120° Horizontal Beam width Antenna:
Used for 2 sectors Base Station, main application is of highway
coverage
Omni and Sectored antenna



Omni-Antenna have
360 degree beam width
in horizontal plane
Sectored Antenna have
directivity in horizontal
and vertical plane both
sectored Antenna are
generally available:
 45° Horizontal
Beam width
 65° Horizontal
Beam width
 90° Horizontal
Beam width
 120°
horizontal
Beam width

18.
Beam-forming Antenna
Beam forming is a signal processing technique used in sensor arrays for
directional signal transmission or reception. This is achieved by
combining elements in a phased array in such a way that signals at
particular angles experience constructive interference while others
experience destructive interference. Beam forming can be used at both
the transmitting and receiving ends in order to achieve spatial
selectivity.
Adaptive Array Antennas are used for Beam-forming at base station.
Array of elements are (vertical polarized) vertically placed at 0.5 λ apart
to have correlated signal which are essential for beam-forming.
The mini requirement for beam forming the antenna should be 4 port or
more.
Beam Forming Antenna
•
•
Adaptive Array
Antennas are used for
Beam-forming
Array of elements are
vertical polarized or
vertically placed at 0.5
λ apart to have
correlated signal which
are essential for beamforming
The above picture shows 4 port and 8 port antenna in first two pictures
which can be used for beam forming. To support 8 transceiver beam
forming requires 8 antenna elements and if placement of element is
vertically then the size of antenna becomes very large , so the alternative
to achieved the same the placement of antenna element can be done
slanted i.e. 45 degree which is also known as cross polarization. This
will reduces the size & weight of Antenna compared to 8 separate
column of vertical polarized Antenna in a single radome as shown in
third picture. From the above pictures it can also be observed that the
antenna elements are 0.5 λ apart from each other to achieve the
correlated signals amongst the different chains
.

19.
Active antenna System
An active antenna is an antenna that contains active electronic components
These active elements are radio cards and amplifiers. In these type of
Remote Radio Head functionality integrated in to antennas. Below shown
picture is an example of active antenna. In this individual radio cards and
amplifier are attached behind the individual dipole.
Active Antenna Systems



The types of antenna are basically next new generation antennas where
only need to connect CPRI/OBSAI interface from the baseband unit.
An active antenna is
an antenna that
contains active
electronic components
These active elements
are radio cards and
amplifiers.
In Active Antenna
Remote Radio Head
functionality integrated
in to antennas.

20.
13. Antenna integration with the base station with
generations
The way in which integration of antenna is done with base station is
changing continually with the generation. In 2G GSM/CDMA system
where both baseband and radio was a single unit. The feeder cables from
the radio of the base station are connected to the antenna. Sometimes
Tower mounted amplifiers are also used to increase the coverage and to
compensate the losses due to feeder cables.
3G WCDMA/ 4G LTE brings the concept of separate baseband and radio
part. In this convention the radio comes closer to antenna and reduces the
losses that were happening in 2G due to long RF feeder cable. The
connection between baseband and radio introduced is CPRI/OBSAI based
which is basically a fiber connection.
Antenna Integration With
basestation with generations



In 2 G/CDMA systems
the feeder cables from
the radio of the base
station are connected to
the antenna
In 3 G the connection
between baseband and
radio introduced is
CPRI/OBSAI based
which is basically a
fiber connection.
The new coming
technology which is
active antenna system
will totally eliminate
use of RF feeder cable
as the radio head
becomes the part of
antenna.
The new coming technology which is active antenna system will totally
eliminate use of RF feeder cable as the radio head becomes the part of
antenna. The based band unit of base station is connected through
CPRI/OBSAI fiber interface. This will eliminate the losses which were
introduced by the RF feeder cables in present topologies.

21.
Authors
14. References
1.
2.
3.
4.
5.
Wikipedia.com
www.3gpp.org
www.commscope.com/docs/active_antenna_systems
www.antenna-theory.com/
Antenna and Wave Propagation by KD Prasad
Wanye Turner
Sytem Design Eningeer
Preet Rekhi
LTE System Test Engineer
Rahul Atri
LTE System Test Engineer
Sukhvinder Malik
LTE System Test Engineer
Disclaimer:
Authors state that this whitepaper has been compiled meticulously and to the best of their
knowledge as of the date of publication. The information contained herein the white
paper is for information purposes only and is intended only to transfer knowledge about
the respective topic and not to earn any kind of profit.
Every effort has been made to ensure the information in this paper is accurate. Authors
does not accept any responsibility or liability whatsoever for any error of fact, omission,
interpretation or opinion that may be present, however it may have occurred