labview based automatic antenna pattern measurement and gain caluclation
TRANSCRIPT
1
EE 491 PROJECT
LABVIEW BASED AUTOMATIC
ANTENNA PATTERN
MEASUREMENT AND GAIN
CALCULATION
SUBMITTED BY:
İsmail YILDIZ – Göksenin BOZDAĞ
SUPERVISOR:
Asst. Prof. Dr. A.Sevinç AYDINLIK BECHTELER
Fall, 2010 – 2011
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CONTENTS
ABSTRACT…………………………………………………………………………………............... 3
A)INTRODUCTION…………………………………………………………………………………… 4
1.LABVIEW PROGRAMMING…………………………………………………………………. 5
2.ANTENNA PATTERN&GAIN………………………………………………………………... 5
B)MEASUREMENT SYSTEM……………………………………………………………………… 6
1.SETTING UP LABVIEW………………………………………………………………………… 9
2.BUILDING VIs.…………………………………………………………………………………… 15
a)Turn Table Control SubVIs……………………………………………………………. 15
b)Signal Generator SubVIs……………………………………………………………. 19
c)Spectrum Analyzer SubVIs……………………………………………………………. 20
3.SETTING UP HARDWARE……………………………………………………………………. 22
C)MEASURUMENTS………………………………………………………………………………… 24
1.Antenna Pattern Measurement………………………………………………………… 27
a)Horn Antenna………………………………………………………………………………. 27
b)Log-Periodic Antenna……………………………………………………………………. 30
2.Antenna Gain Calculation………………………………………………………………….. 31
a)Horn Antenna……………………………………………………………………………….. 31
b)Log-Periodic Antenna …………………………………………………………………… 32
D)CONCLUSION………………………………………………………………………………………. 33
E)REFERENCES…………………………………………………………………………………………. 34
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ABSTRACT
The ambition of the project is developing an automated antenna pattern measurement and
gain calculation system. Hardware components of the system are used in remote mode and
they are controlled by a computer program written in LabView. All of the antenna
measurements are done in a anechoic chamber. Finally, antenna patterns are got on polar
diagrams and gains are calculated automatically.
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A)INTRODUCTION
As a result of the growth in wireless communications, the design and testing of antennas
takes on renewed importance. Two important performance characteristics of antennas are
their radiation pattern and their gain. The pattern is plotted to describe how power radiation
varies with direction around the antenna and the gain is simply defined as the product of
the directivity by efficiency.
The ambition of this thesis project is developing an “automated antenna pattern
measurement and gain calculation” system. Hardware requirements of the system are a
signal generator, a spectrum analyzer, a turn table with controller and a laptop. All hardware
components are used in remote mode and connection of them with laptop is supplied by
GPIB (General Purpose Interface Bus) cables. Remote applications and the other automation
process are managed and controlled by software solution of the system, LabView.
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1.LABVIEW PROGRAMMING
Laboratory Virtual Instrument Engineering Workbench, a product of National Instruments, is
a powerful software system that accommodates data acquisition, instrument control, data
processing and data presentation. LabVIEW that can run on PC under Windows, Sun SPAR
stations as well as on Apple Macintosh computers, uses graphical programming language (G
language), departing from the traditional high level languages such as the C language, Basic
or Pascal.
All LabVIEW graphical programs , called Virtual Instruments or simply VIs, consist of a Front
Panel and a Block Diagram. Front Panel contains various controls and indicators while the
Block Diagram includes a variety of functions. The functions (icons) are wired inside the
Block Diagram where the wires represent the flow of data. The execution of a VI is data
dependant which means that a node inside the Block Diagram will execute only if the data is
available at each input terminal of that node. By contrast, the execution of a traditional
program, such as the C language program, follows the order in which the instructions are
written.
LabVIEW incorporates data acquisition, analysis and presentation into one system. For
acquiring data and controlling instruments, LabVIEW supports IEEE-488 (GPIB) and RS-232
protocols as well as other D/A and A/D and digital I/O interface boards. The Analysis Library
offers the user a comprehensive array of resources for signal processing, filtering, statistical
analysis, linear algebra operations and many others. LabVIEW also supports the TCP/IP
protocol for exchanging data between the server and the client.
2.ANTENNA PATTERN & GAIN
Antenna pattern can be called as amplitude pattern or radiation pattern. The antenna
pattern is a graphical representation in three dimensions of the radiation of the antenna as a
function of angular direction. Antenna radiation performance is usually measured and
recorded in two orthogonal principal planes (such as E-Plane and H-plane or vertical and
horizontal planes). The pattern is usually plotted either in polar or rectangular coordinates.
The pattern of most base station antennas contains a main lobe and several minor lobes,
termed side lobes. A side lobe occurring in space in the direction opposite to the main lobe is
called back lobe. Antenna patterns are generally used in normalized type. A normalized
pattern means that the power/field with respect to its maximum value yields a normalized
power/field pattern with a maximum value of unity (or 0 db).
The maximum gain of an antenna is simply defined as the product of the directivity by
efficiency. If the efficiency is not 100 percent, the gain is less than directivity. When the
reference is a loss less isoterapic antenna, the gain is expressed in dBi. When the reference is
a half-wave dipole antenna the gain is expressed in dBd. (1 dBd = 2.15 dBi)
B) MEASUREMENT SYSTEM
Our measuremet system is based on LabView programing. It supplies us to configure and
control the neccessary devices and process the collected data. The measurement
in a anechoic chamber that is a room to design for stopping reflections of either sound or
electromagnetic waves. Figure 1
Figure 1
Signal generator generates the sig
and this signal is sent by the transmitted antenna. The receiver antenna is placed on a turn
table and it is connected to spectrum analyzer. This receiving sub system provides us to
observe the radiated signal between 0 and 360 degree with desired steps or ranges. For each
step, we get the data of radiated signal from spectrum analyzer. Then, the collected data is
written in a text file. At the same time, this is sourced to draw pattern of antenna on p
diagram. Maximum power value is selected among the data to calculate the gain. All of this
operations are managed with the LabView program set on a laptop.
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B) MEASUREMENT SYSTEM
Our measuremet system is based on LabView programing. It supplies us to configure and
control the neccessary devices and process the collected data. The measurement
in a anechoic chamber that is a room to design for stopping reflections of either sound or
electromagnetic waves. Figure 1 is general hardware structure of the system.
Figure 1 (General Hardware Structure)
Signal generator generates the signal with desired power and frequency for transmission
and this signal is sent by the transmitted antenna. The receiver antenna is placed on a turn
table and it is connected to spectrum analyzer. This receiving sub system provides us to
d signal between 0 and 360 degree with desired steps or ranges. For each
step, we get the data of radiated signal from spectrum analyzer. Then, the collected data is
written in a text file. At the same time, this is sourced to draw pattern of antenna on p
diagram. Maximum power value is selected among the data to calculate the gain. All of this
operations are managed with the LabView program set on a laptop.
Our measuremet system is based on LabView programing. It supplies us to configure and
control the neccessary devices and process the collected data. The measurements are done
in a anechoic chamber that is a room to design for stopping reflections of either sound or
general hardware structure of the system.
nal with desired power and frequency for transmission
and this signal is sent by the transmitted antenna. The receiver antenna is placed on a turn
table and it is connected to spectrum analyzer. This receiving sub system provides us to
d signal between 0 and 360 degree with desired steps or ranges. For each
step, we get the data of radiated signal from spectrum analyzer. Then, the collected data is
written in a text file. At the same time, this is sourced to draw pattern of antenna on plot
diagram. Maximum power value is selected among the data to calculate the gain. All of this
Figure 2 (LabView Front Panel
Figure 2 is “Front Panel” of the software and it is used as a user interface. User selects the visa address of each device and determines speed,
start-stop degrees, step size for turn table; signal type, frequency, power for signal generator; reference level, center and span
spectrum analyzer. After determining all configurations program is run. While program is running user can observe radiated signal
step on the black boxes. As soon as program finishes, antenna pattern is drawn on the white box.
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Figure 2 (LabView Front Panel – User Interface)
d it is used as a user interface. User selects the visa address of each device and determines speed,
stop degrees, step size for turn table; signal type, frequency, power for signal generator; reference level, center and span
rum analyzer. After determining all configurations program is run. While program is running user can observe radiated signal
step on the black boxes. As soon as program finishes, antenna pattern is drawn on the white box.
d it is used as a user interface. User selects the visa address of each device and determines speed,
stop degrees, step size for turn table; signal type, frequency, power for signal generator; reference level, center and span frequencies for
rum analyzer. After determining all configurations program is run. While program is running user can observe radiated signals for each
Figure 3 is “Block Diagram” of the software and it is called VI. All configuration, control, arithmetic and logic operations
diagram. We have 5 main subVIs and they also have their own several subVIs. 3 of main subVIs are used
and two of them in the loop are used to other operations such as turning the table, getting data and measurement. Additional
for loop is used to draw normalized polar diagram and a math node is used for
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Figure 3 (Labview Build Diagram)
Figure 3 is “Block Diagram” of the software and it is called VI. All configuration, control, arithmetic and logic operations
diagram. We have 5 main subVIs and they also have their own several subVIs. 3 of main subVIs are used to configure the necessary devices
and two of them in the loop are used to other operations such as turning the table, getting data and measurement. Additional
for loop is used to draw normalized polar diagram and a math node is used for gain calculation.
Figure 3 is “Block Diagram” of the software and it is called VI. All configuration, control, arithmetic and logic operations are done in the
to configure the necessary devices
and two of them in the loop are used to other operations such as turning the table, getting data and measurement. Additionally, these VIs, a
1.SETTING UP LABVIEW
a) Install LabView 8.0
LabView 8.0 has three CDs and we use two of them for installation. The first CD has
LabView main program, the second CD has MAX (Measurement and Automation)
program and the other one has some driv
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1.SETTING UP LABVIEW
Install LabView 8.0
LabView 8.0 has three CDs and we use two of them for installation. The first CD has
LabView main program, the second CD has MAX (Measurement and Automation)
program and the other one has some drivers. Installation steps are shown below.
Figure 4
LabView 8.0 has three CDs and we use two of them for installation. The first CD has
LabView main program, the second CD has MAX (Measurement and Automation)
ers. Installation steps are shown below.
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Figure 6
Figure 7
Second CD is taken and Rescan Drive button is clicked
11
Figure 8
Second CD is taken and Rescan Drive button is clicked
Figure 9
Second CD is taken and Rescan Drive button is clicked.
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b) Install Agilent 14.1
Although our laboratory instruments have their own GPIB ports, our computers do not have
any GPIB port but our computers have many USB ports. To get communication between
these different ports, we have to use a converter device (GPIB to USB). Our GPIB to USB
converter is produced by Agilent. On the other hand, LabView program is developed by
National Instruments. In LabView, MAX is used to control and get a communication with
instruments. MAX usually detects so many devices using GPIB, USB or etc. But, if the GPIB to
USB converter is not produced by National Instrument, MAX does not detect the devices. To
resolve this incompatibility, we have to do some extra process.
Figure 10
Firstly, we have to install the driver of our converter (Agilent 82357A, shown in above). In
this project, we use Agilent’s converter so we have to install Agilent 14.1 driver.
Figure 11
13
Figure 12
Figure 13
After installing Agilent driver, now we can connect the converter between PC and
instrument. When we plug the instrument, a window appears on the Agilent program and
we enter the GPIB address of instrument. Then, we see the instrument on the left side of
Agilent’s program. To detect this instrument with MAX, we also fallow these steps.
c) Measurement & Automation (MAX) Explorer Configuration
As we see above, MAX is opened
“NI-VISATulip.dll – NI-VISA Passport for Tulip”
restarting the MAX, we get a new tab “
under Tools tab.
14
Measurement & Automation (MAX) Explorer Configuration
Figure 14
As we see above, MAX is opened and Tools/NI-Visa/Visa Options/Passports
VISA Passport for Tulip” is checked at the right of the window. After
restarting the MAX, we get a new tab “Soft Front Panel/VA-Agilent Visa Assistant Utility”
Figure 15
Measurement & Automation (MAX) Explorer Configuration
/Passports is selected and
is checked at the right of the window. After
Agilent Visa Assistant Utility”
When we selected VA-Agilent Visa Assistant Utility, a window that helps us to configure the
instrument appears. We select “Browse” button and choose this path
C:\\Program Files\Agilent\IO Libraries Suite
2.BUILDING VIs
a)Turntable SubVIs
Our turntable is a product of Innco Systems, Germany. A controller called CO 2000 and
produced by Innco systems is used for
GPIB port so we use this port for co
number is used in the program .
Two main subVIs are generated. One of them is for configuration, the other one is for
manipulation.
Turntable Configuration VI
Left side of VI includes controls and the right side includes indicators/connection nodes. We
choose the GPIB address of turntable for VISA session control. Start ,Stop and Step size are
entered by user in degree and user enters the turning speed of turntable in a ran
to 8. When we look at the right side, we see a VISA resource name out, this indicator shows
us which visa address is used in
rotation direction of turntable (clockwise or counter clockwise)
buffers show the values of initially determined.
15
Agilent Visa Assistant Utility, a window that helps us to configure the
instrument appears. We select “Browse” button and choose this path
IO Libraries Suite\Bin\iocfg32.exe
a)Turntable SubVIs
Our turntable is a product of Innco Systems, Germany. A controller called CO 2000 and
produced by Innco systems is used for controlling the turntable. CO 2000 controller has a
GPIB port so we use this port for communication. It’s default GPIB address is 7 and this
number is used in the program .
Two main subVIs are generated. One of them is for configuration, the other one is for
Turntable Configuration VI
Figure 16
VI includes controls and the right side includes indicators/connection nodes. We
choose the GPIB address of turntable for VISA session control. Start ,Stop and Step size are
entered by user in degree and user enters the turning speed of turntable in a ran
to 8. When we look at the right side, we see a VISA resource name out, this indicator shows
which visa address is used in the vi. TF (True-False) case helps us
rotation direction of turntable (clockwise or counter clockwise). Start, stop and step size
buffers show the values of initially determined.
Agilent Visa Assistant Utility, a window that helps us to configure the
instrument appears. We select “Browse” button and choose this path
Our turntable is a product of Innco Systems, Germany. A controller called CO 2000 and
controlling the turntable. CO 2000 controller has a
mmunication. It’s default GPIB address is 7 and this
Two main subVIs are generated. One of them is for configuration, the other one is for
VI includes controls and the right side includes indicators/connection nodes. We
choose the GPIB address of turntable for VISA session control. Start ,Stop and Step size are
entered by user in degree and user enters the turning speed of turntable in a range from 1
to 8. When we look at the right side, we see a VISA resource name out, this indicator shows
False) case helps us determining the
. Start, stop and step size
Figure 17 (inner part of turntable configuration VI, it has also four different subVIs)
Figure 18 (initialize VI of turntable configuration VI)
16
e 17 (inner part of turntable configuration VI, it has also four different subVIs)
Figure 18 (initialize VI of turntable configuration VI)
e 17 (inner part of turntable configuration VI, it has also four different subVIs)
Figure 19 (Speed Co
Figure 20 (This
17
Figure 19 (Speed Control subVI of turntable configuration VI)
This subVI makes turntable to go to desired degree)
ntrol subVI of turntable configuration VI)
desired degree)
Turntable control VI
This VI has two different version but it includes only one subVI. One of the versions is
used for counter clockwise direct
Figure 21 ( Counter Clockwise turning subVI)
Figure 22 (Clockwise turning subVI)
Note: All of the string commands can be found between the pages 35 and 43 in the service
manual of Innco Systems.
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This VI has two different version but it includes only one subVI. One of the versions is
used for counter clockwise direction and the other one is used for clock
Figure 21 ( Counter Clockwise turning subVI)
Figure 22 (Clockwise turning subVI)
Note: All of the string commands can be found between the pages 35 and 43 in the service
This VI has two different version but it includes only one subVI. One of the versions is
ion and the other one is used for clockwise.
Note: All of the string commands can be found between the pages 35 and 43 in the service
b)Signal Generator SubVI
This VI is used for the configuration of the desired transmitted signal. We can adjust signal
type, frequency and power. Our signal generator is Agilent
drivers are found on the library of National
Figure 24 (Developed signal generator VI
19
)Signal Generator SubVI
This VI is used for the configuration of the desired transmitted signal. We can adjust signal
type, frequency and power. Our signal generator is Agilent/HP 83620B and it’s necessary visa
drivers are found on the library of National Instrument web-site.
Figure 23
Figure 24 (Developed signal generator VI including NI drivers)
This VI is used for the configuration of the desired transmitted signal. We can adjust signal
83620B and it’s necessary visa
NI drivers)
c)Spectrum Analyzer SubVI
We developed two subVIs for Spectrum Analyzer. One of them is used for configuration and
the other one is used for measurements.
necessary visa drivers are found on the library of National Instruments web
Spectrum Analyzer Configuration VI
Figure 25 (We can adjust center and span frequency, amplitude scale and reference lev
Figure 26 (Developed Spectrum analyzer Configuration VI including NI drivers)
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c)Spectrum Analyzer SubVI
We developed two subVIs for Spectrum Analyzer. One of them is used for configuration and
the other one is used for measurements. Our spectrum analyzer is Agilent/HP 8565E and it’s
necessary visa drivers are found on the library of National Instruments web
Spectrum Analyzer Configuration VI
We can adjust center and span frequency, amplitude scale and reference lev
Figure 26 (Developed Spectrum analyzer Configuration VI including NI drivers)
We developed two subVIs for Spectrum Analyzer. One of them is used for configuration and
Our spectrum analyzer is Agilent/HP 8565E and it’s
necessary visa drivers are found on the library of National Instruments web-site.
We can adjust center and span frequency, amplitude scale and reference level)
Figure 26 (Developed Spectrum analyzer Configuration VI including NI drivers)
Spectrum Analyzer Measurement VI
NOTE: All of the necessary drivers for the used devices can be found on the web site of
National Instruments at the LabVIEW developer zone.
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Spectrum Analyzer Measurement VI
Figure 27
Figure 28
NOTE: All of the necessary drivers for the used devices can be found on the web site of
ments at the LabVIEW developer zone.
NOTE: All of the necessary drivers for the used devices can be found on the web site of
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3. SETTING UP HARDWARE Connection between laboratory instruments is supplied with GPIB cables. An USB GPIB is
used to connect laptop to instruments. Signal generator, spectrum analyzer and turntable
controller are connected to each other. Usb side of usb gpib is connected to laptop and the
other side is connected to one of the instruments. Almost 5 meters coaxial cable and many
connectors are used. Coaxial cables are supplied connection between instruments and
antennas. Connectors are used to connection between different types of inputs. Signal
generator is connected to transmitter antenna, spectrum analyzer is connected to receiver
antenna, turntable controller is connected to turntable with its own cable.
Fig.29 (Coaxial cable) Fig.30 (Connector) Fig.31 (Connector)
Figure 32 (Coaxial cable is connected to an instrument with a connector)
23
Fig.33 (GPIB cable) Figure 34 ( Instruments are ready to measurement)
Figure 35 (Antennas are ready to measurement in the anechoic chamber)
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C) MEASUREMENT
A major difficulty encountered when trying to measure antenna patterns is a phenomenon
called multipath distortion, in which unwanted reflections of the transmitted signal arrive at
the antenna under test and interfere with the direct signal. The multipath distortion signal
distorts the measured antenna pattern. Another characteristic of multipath distortion is that
all the reflected signals arrive at the test antenna with a time delayed from the direct signal.
However, we can reduce multipath distortion effects by using a large, open outdoor test site
for the antenna range or by taking measurements inside an anechoic chamber. An anechoic
chamber has walls that absorb RF radiation, reducing the reflected signals. We chose
LabVIEW software for digital data collection and display control on the antenna range. We
can apply LabVIEW signal-processing techniques to the pattern measurement data to reduce
the range multipath distortion effects. To mitigate the multipath distortion effects, we used
time-domain processing of the received signals.For the measurement, we used far field
technique where the antenna under test (AUT) is place in the far field of a range antenna.
d=
where d=far field distance, D=maximum dimension of antenna, λ=wavelength
λ =
f =
=
. = 5.83GHz
We can do our measurement until 5.83GHz
For 1GHz:
λ=
=
3108
1109 =0.3m
Path Loss: PL =20log(
) = 20log(
.
.) = 42dB
Cable Loss(Measured): 6.7dB
For 2GHz:
λ=
=
3108
2109 =0.15m
Path Loss: PL =20log(
) = 20log(
.
.) = 48dB
Cable Loss(Measured): 9.06dB
For 3GHz:
λ=
= 310
8
3109 =0.1m
Path Loss: PL =20log(
)
Cable Loss(Measured): 15.84
All of the used antennas are linearly polarized so it provides to analyze the antenna as a
radiation pattern.
• AH SAS-571 Horn Antenna:
Frequency Range:
Antenna Factor:
Gain (dBi):
Maximum Continuous Power:
3dB Beam width (E-Field):
3dB Beam width (H-Field):
Impedance:
E - Plane
25
) = 20log(.
. = 51.5dB
.84dB
antennas are linearly polarized so it provides to analyze the antenna as a
571 Horn Antenna:
700 MHz - 18 GHz
22 to 44 dB
1.4 to 15 dBi
Maximum Continuous Power: 300 Watts
Field): 48°
Field): 30°
50
H - Plane
antennas are linearly polarized so it provides to analyze the antenna as a
• SAS-510-2 Lop-Periodic Antenna:
Frequency Range:
Antenna Factor:
Gain:
Maximum Continuous Power:
3dB Beam width (E-Field):
3dB Beam width (H-Field):
Impedance:
• HLP-3003C Compact Hybrid Log Periodic Antenna:
Frequency Range:
Gain:
Maximum Continuous Power:
Impedance:
H - Plane
H - Plane
26
Periodic Antenna:
290 MHz – 2 GHz
14 - 32 dB
6.5 dBi
uous Power: 1000 Watts
Field): 45°
Field): 100°
50
3003C Compact Hybrid Log Periodic Antenna:
30 MHz – 3 GHz
6 dBi
Maximum Continuous Power: 100 Watts
50Ω
E - Plane
Plane
E - Plane
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1.Antenna Pattern Measurement
a) Horn Antenna
H-Plane Measurements: “For a linearly polarized antenna, the plane containing the magnetic field vector and the
direction of maximum radiation". For base station antenna, the H-plane usually coincides
with the horizontal plane.
For 1GHz: For 1.5GHz:
For 2GHz: For 2.5GHz:
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For 3GHz: For 4GHz:
E-Plane Measurements:
"For a linearly polarized antenna, the plane containing the electric field vector and the
direction of maximum radiation". For base station antenna, the E-plane usually coincides
with the vertical plane.
For 1GHz: For 1.5GHz:
For 2GHz:
For 3GHz:
E-Plane
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For 2.5GHz:
For 4GHz:
H-Plane
b) Log Periodic Antenna
H-Plane Measurements
For 300MHz:
30
Original Pattern
b) Log Periodic Antenna
Plane Measurements
For 1GHz:
2. Antenna Gain Calculation
We developed two different way
determining all of the losses and the gains in measure
second way is comparative (relative) me
The First Way: The key idea of this way is that power desiring to transmit have to equal to
sum of all losses and gains. Initially, we determined the two main losses caused from coaxial
cables and path loss.
1GHz for Horn Antenna: (13+6+RX Gain)=(
2GHz for Horn Antenna: (13+6+RX Gain)=(
3GHz for Horn Antenna: (13+6+RX Gain)=(
Frequency
1GHz
2GHz
3GHz
The Second Way: The key idea of this way is calculating the gain comparatively or relatively.
We use two antennas, one of them is ref
gain is desiring to find. The formula shown below
calculate the gain.
a)Horn Antenna
1GHz for Horn Antenna: Gain
2GHz for Horn Antenna: Gain
3GHz for Horn Antenna: Gain
Frequency Calculated Gain(dBi)
1GHz 7.3
2GHz 9.02
3GHz 11.7
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2. Antenna Gain Calculation
two different ways for calculation of antenna gain. The first way
the losses and the gains in measurement system and the key idea of
is comparative (relative) measurement of antenna gains.
The key idea of this way is that power desiring to transmit have to equal to
Initially, we determined the two main losses caused from coaxial
(13+6+RX Gain)=(-23.33)+(6.7+42) RX Gain=6.37dBi
(13+6+RX Gain)=(-28.83)+(9.06+48) RX Gain=9.23dBi
(13+6+RX Gain)=(-37.33)+(15.84+51.5) RX Gain=11.0
Calculated Gain Original Gain
6.37 7.3
9.23 8.6
11.01 10
The key idea of this way is calculating the gain comparatively or relatively.
one of them is reference that its gain is known before,
o find. The formula shown below helps us to understand the way and
Gain =7.3 .
. = 7.3dBi
Gain =7.3 .
. = 9.02dBi
Gain =7.3 .
. = 11.7dBi
Calculated Gain(dBi) Original Gain(dBi)
7.3 7.3
9.02 8.6
11.7 10
for calculation of antenna gain. The first way is based on
ment system and the key idea of the
The key idea of this way is that power desiring to transmit have to equal to
Initially, we determined the two main losses caused from coaxial
23.33)+(6.7+42) RX Gain=6.37dBi
28.83)+(9.06+48) RX Gain=9.23dBi
37.33)+(15.84+51.5) RX Gain=11.01dBi
The key idea of this way is calculating the gain comparatively or relatively.
that its gain is known before, the other’s
helps us to understand the way and
32
b)Log-periodic Antenna
300MHz for Log Periodic Antenna: Gain =7.3 .
. = 3.54dBi
1GHz for Log Periodic Antenna: Gain =7.3 .
. = 6.78dBi
Frequency Calculated Gain(dBi) Original Gain(dBi)
300GHz 3.54 5.6
1GHz 6.78 7.2
As a result of several measurements and calculations, it is clear that the second way is more
accurate because losses are ignored.
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D) CONCLUSION
The importance and utilization area of antennas are getting increased and as a result of
this situation, characterization problem of antenna is being critical day by day. So many
systems are designed by researchers at universities and so many systems are produced
commercially by companies to solve this critical problem.
In this thesis project, we developed an antenna characterized system. LabView provide a
highly effective and efficient solution for our system. The pattern and directivity of antenna
is measured almost same as the original values. The gain is calculated by two different
methods and the results of these calculations are almost same as the originals, too.
As a conclusion, the initial ambitions of the our thesis project are reached. Measurements
and calculations are acceptable and reliable.
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E) REFERENCES
Books
1. Bishop, Robert H. , Labview Student Edition 6i, National Instruments
2. LabVIEW Getting Started, National Instruments, April 2003
3. Jeffrey Travis, Jim Kring, LabVIEW for Everyone: Graphical Programming Made Easy
and Fun, Printice-Hall Third Edition
4. David M. Pozar, Microwave Engineering, John Willey & Sons Second Edition
Papers
1. S. Burgos., S. Pivnenkot, 0. Breinbjergt, M. Sierra-Castafier, Comparative
Investigation of Four Antenna Gain Determination Techniques (pdf)
2. Leonard Skaloff, DeVry College of Technology, GPIB Instrument Control (pdf)
3. Innco Systems, Operating and Service Manual (pdf)
4. Tips on Using agilent GPIB Solutions in National Instrument’s LabVIEW Environment, Agilent Technologies 2009 USA (pdf)
Web-Sites 1. http://zone.ni.com/dzhp/app/main (NI LabVIEW Developer Zone)
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