In this paper, a system has been designed for an operational frequency of 1.27 GHz consisting of an 8 element array of parasitic dipoles illuminated by a 4 element center fed array of active dipoles with Dolph-Chebyshev excitation coefficients. The array is designed to achieve a fairly pencil beam pattern suitable for direction of arrival estimation purposes. Array geometry and configuration is optimized for both active and parasitic elements using the PSO tool in FEKO. A directive radiation pattern is obtained with a gain of 14.5 dBi in the broadside direction along with a beamwidth of 30.29o. VSWR of 1.58 is achieved. Further, an iterative least square valued error estimation approach using phase control to achieve a desired array factor pattern for an n-element linear array, has been shown to be effective for larger number of iterations. The array excitation coefficients achieved were consistent with the Dolph-Chebyshev coefficients used in our antenna array design. With the ability to introduce nulls and steering the main beam in desired directions along with a pencil beam radiation pattern, beamsteering has been illustrated and the MUSIC algorithm for direction of arrival estimation has been implemented
Implementation of Digital Beamforming Technique for Linear Antenna Arraysijsrd.com
A digital Beamforming technique used for increased channel capacity and also increased signal to noise and interference ratio. In smart antenna, different type of radiation pattern of an antenna can be changed either by selecting appropriate weights or by changing the array geometry. This paper presented based on auxiliary phase algorithm by using this algorithm in linear antenna array determine the array pattern approximating the auxiliary function in both amplitude and phase. Cost function involving auxiliary function and array pattern is minimized by modifying the pattern.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
Four-Element Triangular Wideband Dielectric Resonator Antenna excited by a Co...IOSR Journals
Abstract-This paper numerically examines an array of four dielectric resonant antenna of equilateral triangle
shape. The Structure provides wideband low profile monopole-like antenna. As much as 30.90 % matching
bandwidth (S11<-10 dB) with monopole-like radiation pattern over the entire band has been achieved with 6.357
dBi peak gain. The geometry is a four equilateral triangular dielectric volume over a ground plane, and is
centrally excited by a coaxial probe to provide a broadside radiation pattern. An approximate expression is
used to compute the resonance frequency. Results are simulated using CST (Computer Simulation Technology)
Microwave Studio Suite 10.
Keywords-Dielectric resonator (DR), triangular dielectric resonator antenna (TDRA), S11 (S-Parameter),
perfect conductor (PEC), Impedance Bandwidth (IBW).
Implementation of Digital Beamforming Technique for Linear Antenna Arraysijsrd.com
A digital Beamforming technique used for increased channel capacity and also increased signal to noise and interference ratio. In smart antenna, different type of radiation pattern of an antenna can be changed either by selecting appropriate weights or by changing the array geometry. This paper presented based on auxiliary phase algorithm by using this algorithm in linear antenna array determine the array pattern approximating the auxiliary function in both amplitude and phase. Cost function involving auxiliary function and array pattern is minimized by modifying the pattern.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
Four-Element Triangular Wideband Dielectric Resonator Antenna excited by a Co...IOSR Journals
Abstract-This paper numerically examines an array of four dielectric resonant antenna of equilateral triangle
shape. The Structure provides wideband low profile monopole-like antenna. As much as 30.90 % matching
bandwidth (S11<-10 dB) with monopole-like radiation pattern over the entire band has been achieved with 6.357
dBi peak gain. The geometry is a four equilateral triangular dielectric volume over a ground plane, and is
centrally excited by a coaxial probe to provide a broadside radiation pattern. An approximate expression is
used to compute the resonance frequency. Results are simulated using CST (Computer Simulation Technology)
Microwave Studio Suite 10.
Keywords-Dielectric resonator (DR), triangular dielectric resonator antenna (TDRA), S11 (S-Parameter),
perfect conductor (PEC), Impedance Bandwidth (IBW).
A RRAY F ACTOR O PTIMIZATION OF AN A CTIVE P LANAR P HASED A RRAY USING...jantjournal
Evolutionary algorithms (EAs) have the potential to
handle complex, multi-dimensional optimization
problems in the field of phased array. Out of diffe
rent EAs, particle swarm optimization (PSO) is a po
pular
choice. In a phased array, antenna element failure
is a common phenomenon and this leads to degradatio
n
of the array factor (AF) pattern, primarily in term
s of increased side lobe levels (SLLs), displacemen
t of
nulls and reduction in the null depths. The recover
y of a degraded pattern using a cost and time-effec
tive
approach is on demand. In this context, an attempt
made to obtain an optimized AF pattern after fault
in a
49 elements quasi-circular aperture equilateral tri
angular grid active planar phased array using PSO.
In
the paper, multiple cases on recovery are discussed
having a maximum 20% element failure. Each recover
y
is also further evaluated by different statistical
analyses. A dedicated software tool was developed t
o carry
out the work presented in this paper.
Investigation on the Pattern Synthesis of Subarray Weights for Low EMI Applic...IOSRJECE
In modern radar applications, it is frequently required to produce sum and difference patterns sequentially. The sum pattern amplitude coefficients are obtained by using Dolph-Chebyshev synthesis method where as the difference pattern excitation coefficients will be optimized in this present work. For this purpose optimal group weights will be introduced to the different array elements to obtain any type of beam depending on the application. Optimization of excitation to the array elements is the main objective so in this process a subarray configuration is adopted. However, Differential Evolution Algorithm is applied for optimization method. The proposed method is reliable and accurate. It is superior to other methods in terms of convergence speed and robustness. Numerical and simulation results are presented.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
Variable radiation pattern from co axial probe fed rectangular patch antenna ...eSAT Journals
Abstract The idea of obtaining variable radiation patterns from the same antenna is important aspect in achieving the adaptive antenna systems. In the EM signal processing the change of radiation signifies the information to be transmitted, its rate of transmission, the geographical changes and direction to transmit etc. i.e. each time when the requirement arises to change the radiation pattern it has to be done to satisfy the conditions. Electronically steerable antennas were used where the antenna radiation will be altered by varying the feed and similar case is applied for shaped patterns from array antenna where the feed to be given will be calculated and given accordingly. In the present concept the metamaterials are used to obtain different radiation patterns occurred at different operating frequencies using the same antenna without changing the antenna physically are varying its feed. Key Words: Inductance, capacitance, operating frequency, variable radiation, enhancement, radiation cancellation.
Validation of Polarization angles Based Resonance Modes IJERA Editor
The symmetry, tilt and elongation degrees are figures of merit which can be used to describe the radar target
shape once incorporated with the target resonance modes. Through optimization of the second moments of the
quadrature-polarized residues matrix, the angles are determined by the optimum co-null polarization states. The
approach is tested and validated against low signal-to-noise ratio and also the late-time onset selection when
extracting the mode set. A wire plane model is used and the results show that with ensemble averaging it
possible to have robust polarization angle set, even with small number of sample set
Direction of Arrival Estimation Based on MUSIC Algorithm Using Uniform and No...IJERA Editor
In signal processing, the direction of arrival (DOA) estimation denotes the direction from which a propagating wave arrives at a point, where a set of antennas is located. Using the array antenna has an advantage over the single antenna in achieving an improved performance by applying Multiple Signal Classification (MUSIC) algorithm. This paper focuses on estimating the DOA using uniform linear array (ULA) and non-uniform linear array (NLA)of antennas to analyze the performance factors that affect the accuracy and resolution of the system based on MUSIC algorithm. The direction of arrival estimation is simulated on a MATLAB platform with a set of input parameters such as array elements, signal to noise ratio, number of snapshots and number of signal sources. An extensive simulation has been conducted and the results show that the NLA with DOA estimation for co-prime array can achieve an accurate and efficient DOA estimation
A RRAY F ACTOR O PTIMIZATION OF AN A CTIVE P LANAR P HASED A RRAY USING...jantjournal
Evolutionary algorithms (EAs) have the potential to
handle complex, multi-dimensional optimization
problems in the field of phased array. Out of diffe
rent EAs, particle swarm optimization (PSO) is a po
pular
choice. In a phased array, antenna element failure
is a common phenomenon and this leads to degradatio
n
of the array factor (AF) pattern, primarily in term
s of increased side lobe levels (SLLs), displacemen
t of
nulls and reduction in the null depths. The recover
y of a degraded pattern using a cost and time-effec
tive
approach is on demand. In this context, an attempt
made to obtain an optimized AF pattern after fault
in a
49 elements quasi-circular aperture equilateral tri
angular grid active planar phased array using PSO.
In
the paper, multiple cases on recovery are discussed
having a maximum 20% element failure. Each recover
y
is also further evaluated by different statistical
analyses. A dedicated software tool was developed t
o carry
out the work presented in this paper.
Investigation on the Pattern Synthesis of Subarray Weights for Low EMI Applic...IOSRJECE
In modern radar applications, it is frequently required to produce sum and difference patterns sequentially. The sum pattern amplitude coefficients are obtained by using Dolph-Chebyshev synthesis method where as the difference pattern excitation coefficients will be optimized in this present work. For this purpose optimal group weights will be introduced to the different array elements to obtain any type of beam depending on the application. Optimization of excitation to the array elements is the main objective so in this process a subarray configuration is adopted. However, Differential Evolution Algorithm is applied for optimization method. The proposed method is reliable and accurate. It is superior to other methods in terms of convergence speed and robustness. Numerical and simulation results are presented.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
Variable radiation pattern from co axial probe fed rectangular patch antenna ...eSAT Journals
Abstract The idea of obtaining variable radiation patterns from the same antenna is important aspect in achieving the adaptive antenna systems. In the EM signal processing the change of radiation signifies the information to be transmitted, its rate of transmission, the geographical changes and direction to transmit etc. i.e. each time when the requirement arises to change the radiation pattern it has to be done to satisfy the conditions. Electronically steerable antennas were used where the antenna radiation will be altered by varying the feed and similar case is applied for shaped patterns from array antenna where the feed to be given will be calculated and given accordingly. In the present concept the metamaterials are used to obtain different radiation patterns occurred at different operating frequencies using the same antenna without changing the antenna physically are varying its feed. Key Words: Inductance, capacitance, operating frequency, variable radiation, enhancement, radiation cancellation.
Validation of Polarization angles Based Resonance Modes IJERA Editor
The symmetry, tilt and elongation degrees are figures of merit which can be used to describe the radar target
shape once incorporated with the target resonance modes. Through optimization of the second moments of the
quadrature-polarized residues matrix, the angles are determined by the optimum co-null polarization states. The
approach is tested and validated against low signal-to-noise ratio and also the late-time onset selection when
extracting the mode set. A wire plane model is used and the results show that with ensemble averaging it
possible to have robust polarization angle set, even with small number of sample set
Direction of Arrival Estimation Based on MUSIC Algorithm Using Uniform and No...IJERA Editor
In signal processing, the direction of arrival (DOA) estimation denotes the direction from which a propagating wave arrives at a point, where a set of antennas is located. Using the array antenna has an advantage over the single antenna in achieving an improved performance by applying Multiple Signal Classification (MUSIC) algorithm. This paper focuses on estimating the DOA using uniform linear array (ULA) and non-uniform linear array (NLA)of antennas to analyze the performance factors that affect the accuracy and resolution of the system based on MUSIC algorithm. The direction of arrival estimation is simulated on a MATLAB platform with a set of input parameters such as array elements, signal to noise ratio, number of snapshots and number of signal sources. An extensive simulation has been conducted and the results show that the NLA with DOA estimation for co-prime array can achieve an accurate and efficient DOA estimation
JEE Mathematics/ Lakshmikanta Satapathy/ Questions on Indefinite Integration part 12 taken from previous Board papers solve by the method of substitution using standard Integrals
Notes I made in June 2013 on the derivation and use of the Black-Scholes equation. If you can forgive the terseness, you can look forward to some nifty stochastic partial differential equation twirling!
Any and all corrections are welcome!
Modeling Beam forming in Circular Antenna Array with Directional EmittersIJRESJOURNAL
ABSTRACT: The article discusses the functioning of the radio direction-finding and beamforming methods in the system of circular antenna arrays formed from the designed radiators, directional factor which is not equal to 1. Evaluation of forming of spatial pattern of cylindrical antenna array using phased method is fulfilled. DolphChebyshev window is used to reduce the side lobe level.
Design of Non-Uniform Linear Antenna Arrays Using Dolph- Chebyshev and Binomi...IJERA Editor
This paper explores the analytical methods of synthesizing linear antenna arrays. The synthesis employed is
based on non-uniform methods. In particular, the Dolph-Chebyshev and binomial methods are used, so as to
improve the directivity of the array and to reduce the level of the secondary lobes by adjusting the geometrical
and electric parameters of the array. The radiation patterns, the directivity, and the array factors of the uniform
and the non-uniform methods are presented. It is shown that the Chebyshev arrays have better directivity than
binomial arrays for the same number of elements and separation distance, while binomial arrays have very low
side lobes compared with Chebyshev and uniform excitation arrays. Finally, numerical results of both methods
are analyzed and compared.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization
problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular
choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of
nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective
approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In
the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery
is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry
out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a 49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
Direction of arrival estimation using music algorithmeSAT Journals
Abstract The performance of smart antenna greatly depends on the effectiveness of DOA estimation algorithm. This paper analyzed the performance of MUSIC (Multiple Signal Classification) algorithm for DOA estimation. simulation results shows that MUSIC provide better angular resolution for increasing number of array element, distance between array element and number of samples. All the simulations are carried out using MATLAB. Keywords: DOA (Direction of arrival), MUSIC (Multiple signal classification), ULA(Uniform linear array)
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
High Resolution Method using Patch Circular Array IJECEIAES
Smart antennas have recently received increasing for improving the performance of wireless radio systems. In this research article, we have used a patch antenna using uniform circular arrays (UCA) with central element for direction of arrival (DOA). A central element was added to arrays in order to increase steering capability of the proposed array. This geometry is used to determine the elevation and azimuth based on two famous algorithms of high resolution method: Matrix Pencil method (MP) and MUltiple Signal Classification (MUSIC).The comparison results demonstrate clearly that the matrix pencil is more accurate and stable to estimation of direction of arrival compared to the MUSIC algorithm.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Similar to Designing a pencil beam pattern with low sidelobes (20)
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
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Governing Equations for Fundamental Aerodynamics_Anderson2010.pdf
Designing a pencil beam pattern with low sidelobes
1. 1
Abstract— In this paper, a system has been designed for an
operational frequency of 1.27 GHz consisting of an 8 element array of
parasitic dipoles illuminated by a 4 element center fed array of active
dipoles with Dolph-Chebyshev excitation coefficients. The array is
designed to achieve a fairly pencil beam pattern suitable for direction
of arrival estimation purposes. Array geometry and configuration is
optimized for both active and parasitic elements using the PSO tool in
FEKO. A directive radiation pattern is obtained with a gain of 14.5
dBi in the broadside direction along with a beamwidth of 30.29o
.
VSWR of 1.58 is achieved. Further, an iterative least square valued
error estimation approach using phase control to achieve a desired
array factor pattern for an n-element linear array, has been shown to
be effective for larger number of iterations. The array excitation
coefficients achieved were consistent with the Dolph-Chebyshev
coefficients used in our antenna array design. With the ability to
introduce nulls and steering the main beam in desired directions
along with a pencil beam radiation pattern, beamsteering has been
illustrated and the MUSIC algorithm for direction of arrival
estimation has been implemented.
Index Terms—Linear Parasitic Array; Pattern Synthesis; Beam
Steering; DOA Estimation; MUSIC Algorithm
I. INTRODUCTION
Antenna arrays are increasingly being used for a variety of
applications due to their ability to control certain parameters of the
radiation pattern like pattern maximum steering, null angle
placement, increasing the Signal to Interference plus Noise ratio. A
pencil beam radiation pattern is generally obtained by increasing
the effective size of the active array by increasing the number of
elements and element spacing. However this leads to increased
cost, size and complexity. A workaround to this problem is to
make use of the mutual coupling between active and parasitic
elements in the array that allows us to use lesser active feed
elements. This technique also allows parasitic array elements to
introduce degrees of freedom that ensure that pattern can be
synthesized without modification of the active array feed.
Therefore, an 8 element array of parasitic dipoles is illuminated by
a 4 element active array above a finite ground plane to obtain a
pencil beam pattern and its characteristics are observed.
Furthermore, the pattern synthesis problem is crucial to any
array design problem. The desired pattern synthesis problem using
an iterative technique to get a desired radiation pattern is shown to
improve for larger iterations. With the ability to introduce nulls
and steer the beam, Beam steering by changing phases is observed
and the MUSIC algorithm is shown to effectively estimate the
angle of arrival.
II. DESIGN PROCEDURE
We look at the geometry of active/parasitic array combinations
which can be optimized to achieve the desired performance. We
consider the synthesis of low-sidelobe sum patterns generated by
antennas consisting of a parasitic linear array of half-wavelength
dipoles illuminated by similar uniformly fed active array. A real
non-infinite ground plane is included to increase the overall
directivity of the radiation pattern. The parameters which are
manipulated for the pattern synthesis are the distance of the
respective arrays from the ground, distance between adjacent
dipoles in each array and distance between the two arrays. The
effect of mutual coupling between the elements has been taken
care of and accounted by means of FEKO simulation with PSO
optimization. The proposed method is based on the optimization of
the array geometry in order to obtain a highly directive pattern. A
uniformly spaced planar array of parasitic dipoles of length λ/2 is
considered as a starting point in the optimization process. In this
procedure, the distance between the planar array and the ground
plane and the interspacing in the x-axis direction of the parasitic
array are modified. The aim is to find the optimal array geometry
that fulfill the requirements of a given design problem. The
variables mentioned above were optimized by means of PSO to
minimize a cost function C consisting of a term to increase the
directivity in the broadside (Θ=00
, Φ=00
):
C = 1/Directivity (D0) (1)
Taking into account the optimized values we consider an
antenna system consisting of 1.) A non-infinite ground in the x-y
plane with moist soil dielectric whose εr = 30 and tan δ = 0.007;
2.)A linear array of 4 center-fed half-wavelength wire dipoles
oriented parallel and above the x-y plane at a height hactive = λ/4
with their centers located at regular intervals of λ/2 along a line and
3.) A similar linear array of 8 parasitic elements arranged along the
line in the x-y plane at a height hparasitic= 5λ/4. The active dipoles
are excited according to the Dolph-Chebyshev array excitation
coefficients and these have been found out for a 4-element array
system with a side-lobe level to be 30 dB down from the main lobe.
If vector I represents the current distribution on this antenna then it
is given by
I = Z-1
V (2)
where V is the vector of voltages (Vn=22.22 or 9.53 if the element
n is active; Vn=0 if it is parasitic) and Z is the impedance matrix.
Figure 1: Antenna Array Design Schematic with real ground
III. PATTERN SYNTHESIS
Beam forming allows placement of single or multiple nulls in the
antenna pattern at specific interference directions. Prescribed nulls
in the radiation pattern are formed to suppress interferences from
specific directions. For broadband interference, null in the pattern
should be wide and deep enough to suppress peak side lobe levels
at the angular sector of arrival of interference. Nulling methods are
based on controlling complex weights. Having already achieved a
directive pattern for the Dolph-Chebyshev amplitude coefficient
arrangement, we have focused on optimizing array coefficients
further by using phase control.
Designing a pencil beam pattern with low
sidelobes using pattern synthesis technique and a
system of active linear array illuminating
parasitic dipoles
Gaurav Narula(1)
, Piyush Kashyap(2)
(1)(2)
Graduate Student, ECEE Department,
University of Colorado at Boulder
Boulder, CO 80309
United States
(1)
gana2553@colorado.edu, (2)
pika7816@colorado.edu
2. 2
The problem considered is as follows. We want to find a weight
vector W for which the array factor has a beam maximum at some
angle ϴd and meets a given side lobe specification for other angles.
The prerequisites to this problem i.e. number of elements (n) of the
array, element spacing (d), and element patterns are obtained from
the array design performed in FEKO. Consider an n element linear
array as shown in Figure 2. Let fi(ϴ) be the pattern element of each
element.
Figure 2: N-element Linear Array
Let X be the received signal vector with xi(t) being the received
signal on ith element.
X=[x1(t), x2(t), x3(t)….. xn(t)]T
(3)
The array output signal s(t) can be obtained using the following
expression:
s(t) = WT
X (4)
where, W is the weight vector,
X = Aejωo
U is the received signal vector with xi(t) the received
signal on ith element.
Effective array output can be expressed as:
s(t)= Aejω0
WT
U (5)
where A is the signal amplitude, U is a vector that includes inter
element phase shifts and pattern defined as follows
U=[f1 (ϴ) , f2 (ϴ) e-jϕ2(ϴ)
, f3 (ϴ) e –jϕ3(ϴ)
…… fn (ϴ) e–jϕn(ϴ)
]T
dk (6)
The algorithm we deploy to get desired nulls and maxima
essentially finds the vector W for which p(ϴ) = WT
U has a beam
maximum at desired angle ϴd and nulls at other angles. As given in
[9] ,the expression obtained for the weight vector is given by
W = µϕu
-1
Ud
*
(7)
where, Ud is vector of signal from desired direction, Ud
*
is
conjugate of Ud, µ is an arbitrary non zero scalar, ϕu is covariance
matrix of undesired signal, Ui is matrix specified in (8) with ϴ=ϴi
and Ai is the interference amplitude.
Computations based on above formulae are performed on
MATLAB for introducing a null by introducing interference signal
at a specific or range of angles as shown in Fig. 3 and Fig. 4.
(a)
(b)
Figure 3: Adapted patterns with one interference signal at ϴ = π/4 for n =
4element array with ideal isotropic elements (a) INR= -10 dB (b) INR = 10 dB.
These plots show Power variation (in dB) with angle ϴ (in degrees).
Using an iterative technique and the formulations given in [9] the
approach for desired pattern synthesis problem is as follows:
1. The main beam is steered in the desired direction by choosing a
steering vector Ud.
2. To reduce side lobes, a large number of interference signals are
assumed to be incident on the array from side lobe region. Matrix
Ui is generated.
3. Interference amplitude matrix Ai with 32 different combinations
of random numbers is formed to form a pattern P.
4. An adapted weight matrix is created that contains phase
coefficients to be multiplied with each element of the array to get
the desired pattern.
5. 32 adapted patterns are obtained and compared with the design
objective to get an Error matrix.
6. For next iteration, combination with 16 least valued errors are
used as elements of matrix Ai and 16 other random patterns are
obtained using the next16 random numbers in Ai.
After desired number of iterations, of the 32 patterns obtained, the
Weight matrix Wand Interference amplitude matrix Ai for the one
with least deviation is used for the pattern synthesis of the array.
An increase in the number of iterations leads to a better pattern as
shown in Figure 5 where 100 iterations brings down the sidelobe
levels by 10.43 dB approximately.
(a)
(b)
Figure 4: Adapted patterns with 21 interference signals from ϴ = -20o
to -60o
for an 8 element linear array with isotropic elements (a) INR = -10 dB (b) INR
= 10 dB. These plots show Power variation (in dB) with angle ϴ (in degrees).
3. 3
(a)
(b)
(c)
Figure 5: Patterns obtained by the Iteration techniques taking least value
squared error values between desired pattern and obtained patterns (a) Desired
Pattern (b) 100th
iteration (c) 50th
iteration. These plots show Power variation
(in dB) with angle ϴ (in degrees).
IV. RESULTS AND DISCUSSION
A. Gain
The structure parameters have been chosen in such a way that the
VSWR obtained is less than 2 and the antenna gain is maximized
at the frequency of operation. The value of gain obtained is 14.5
dBi as shown below in Figure 7.
Figure 7: Far field Gain pattern for antenna array with real ground plane
B. Radiation Pattern, Beamwidth and VSWR
The E-plane radiation pattern obtained for our antenna array at
operational frequency is below shown in Figure 8.
Figure 8: Electric Field radiation pattern for our antenna array system
At 1.27 GHz, the Half-Power Beamwidth, of our antenna array is
about 30.29o
. This is shown below in Figure 9.
Figure 9: 3dB Beamwidth of antenna array system
VSWR obtained at 1.27 GHz is 1.58, as shown in Figure 10.
Figure 10: VSWR vs Frequency
C. 2:1 VSWR Bandwidth
The obtained 2:1 VSWR bandwidth for our antenna array system is
282 MHz as shown below in the Figure 11.
Figure 11: 2:1 VSWR Bandwidth
D. Performance of antenna array with no parasitic elements
Comparing the results obtained for our antenna array system to that
when there are no parasitic dipoles present in our antenna we found
that, at operational frequency, gain gets reduced to11.5 dBi so as
the directivity. As a result, the 3 dB beamwidth increases to 38.290
.
Values of VSWR and Reflection Coefficient increase to 3.45 and
0.55, respectively. We conclude that using parasitic array of
dipoles does help us achieve substantially better antenna
performance in terms of increase gain (or directivity) and low
reflection coefficient.
E. Effect of height of active and parasitic array from the ground
and distance between the elements
Here we changed the value of hparasitic from 5λ/4 to 3λ/4 and
generated a curve for reflection coefficient which shows a drastic
change in the value of ρ. The new value of reflection coefficient
obtained is about 0.73. This is shown below in Figure 12.
Figure 12: 3dB Beamwidth when hparasitic = 3λ/4