Latest work on null steering in failed antenna arrays is presented in 20. An estimator which makes use of the knowledge of the spatial distribution of the signal. In particular, null steering is a method of beamforming for narrowband signals where we want to have a simple way of compensating delays of receiving signals from a specific source at different elements of the antenna array. Instead of an analytical approach, an evolutionary optimization technique, namely, pso 27 30 was used to reoptimize the excitation of the working elements.
Regularized zeroforcing precoding is enhanced processing to consider the impact on a background noise and unknown user interference, where the background noise. I was introduced to the nx4d 160 meter band dual phased flag arrays by n4is before i went to quoddy head for the first time in october 2008. The average attenuation when steering the position of null. Naveednull placement and sidelobe suppression in failed array using symmetrical. Koziel s and ogurtsov s 2015 phasespacing optimization of linear microstrip antenna arrays using simulationbased surrogate superposition models. But in large antenna arrays, there is always a possibility of failure of some elements, which may degrade the radiation pattern with an increase in side lobe level sll and removal of the nulls from desired position. An inner circular antenna is used as an auxiliary element in nulling interference received by an outer annular ring antenna disposed around the inner antenna. This paper stresses on the problem of failure correction in linear antenna arrays which has many applications in satellite and radar communication systems 15. In most practical cases, they are identical in construction with different feedings. Even though learning capabilities are very limited, the complexity of the organization of the colony allows a very efficient communication among individuals, based upon. Jul 01, 2002 read null steering of linear antenna arrays with use of modified touring ant colony optimization algorithm, international journal of rf and microwave computeraided engineering on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Analysis and simulation of narrow band digitally beamformed. Authors in their previous work haveusedthesymmetrical element failure technique to achieve the required null depthleveland rstnullbeamwidthand forfault nding in failed array antenna. Research article correction of faulty sensors in phased. In active antenna array to obtain a desired radiation pattern with specified sidelobe level, null steering and beamforming is possible by. The waller flag arrays, as they were called, were optimized for maximum rdf. In general to make better use of the antenna arrays, we sum and average the signals coming to different elements, but. Steering the null leads to a depth of 26 db in the worst case and 46 db in the best condition. The outer annular antenna is resonant in a higher order mode but forced to generate a right hand circularly polarized lower. A spatial null steering microstrip antenna array comprising two concentric microstrip patch antenna elements. The antenna array pattern null steering is one of the important current topics in the array synthesis theory, due to its very effectiveness to suppress the interfering signals.
On the other hand, largescale antenna arrays are used to serve many autonomous users at different locations simultaneously, which needs steerable or adaptive antenna arrays, also known as adaptive beamforming. Adaptive arrays can extend the range by focusing most of the radio frequency rf power on a desired target. Detection and correction of failed element in array antenna is a problem of concern for the researchers. Kothariant lion optimization algorithm to control side lobe level and null depths in linear antenna arrays. The performance of a nullsteering beamformer in correlated rayleigh fading cornelius van rensburg, benjamin friedlander. Antenna array a configuration of multiple antennas elements arranged to achieve a given radiation pattern. But the null steering problem in failed arrays was not addressed in the literature. Section iv applies these techniques to arrays with no failed elements to modify either the taper loss or the sidelobe level.
Instead of an analytical approach, an evolutionary. Each antenna in an array is called an element antenna or simply an element. If a single sensor fails, the radiation power pattern of the entire array is disturbed in terms of sidelobe level sll and null depth level ndl, and nulls are damaged and shifted from their original locations. Ga 19 technique have been used for correcting element failures in antenna arrays. Atom search optimization algorithm based hybrid antenna array receive beamforming to control sidelobe level and steering the null. This paper illustrates the analysis and simulation of narrow band antenna arrays with adapted radiation pattern using digital beamformation. The software enables to compute antenna array radiation patterns and antenna parameters. A single element failure gives rise to sidelobes, diminishing of nulls depth, null shifting etc. Linear array antenna elements arranged along a straight line. Us20182785a1 system and methods for null steering in a. If a single sensor fails, the radiation power pattern of the entire array is disturbed. Null steering in failed antenna arrays, applied computational intelligence and soft computing hindawi, vol.
Spaa software spaa that has been written with matlab basis is a powerful tool to synthesis and analysis of linear and planar array antenna. An overview of adaptive antenna systems, hafeth hourani, helsinki university of technologyparticularly fig. Pdf antenna array pattern nulling is desirable in order to suppress the interfering signals. To understand antenna arrays and phased arrays, navigate through the following pages. In a radio receiver the receivers antenna can be adjusted so the direction of the interference source is located in a null of the antenna, to minimize reception of interference. Null positioning of linear antenna array using evolutionary. In particular, the research shows that designers should focus on an elements null steering capability rather than beam tilting capacity. Abstract and applied analysis active and passive electronic components advances in agriculture advances in astronomy advances in civil engineering advances in condensed matter physics advances in fuzzy systems advances in hematology advances in high energy physics advances in humancomputer interaction advances in materials science and engineering advances in. Antenna arrays have been used in mobile, wireless, radar communication and in many signal acquisition applications. All the above ec based techniques have discussed the sll reduction and null steering in failed array, but no one is solving the issue of null depth and null steering at their. The proposed method was validated by considering few examples of pattern synthesis with null steering of a linear antenna array with defective elements. Correction of failure in linear antenna arrays with greedy sparseness.
Atom search optimization algorithm based hybrid antenna. Antenna array pattern nulling is desirable in order to suppress the interfering signals. Recently, evolutionary algorithms such as particle swarm optimization pso 7, simulated. Atom search optimization algorithm based hybrid antenna array. On the other hand, nulls can also be used to advantage. There are different parts in this software including, jammer properties which contains number of jammers, their power. Mediumsized low band rx antenna solutions gary breed, k9ay expanded version of a presentation at the w9dxcc convention september 15, 2007, elk grove village, il with the low bands benefitting from the current sunspot minimum, receive antennas are important for dxers, contesters and other active amateur radio operators. But our proposed method recovered the sidelobe level and null placement at the desired locations as shown in fig 10. Most of the methods of null steering available in the literature. Patnaik a and sinha s 2018 null steering in failed antenna arrays, applied computational intelligence and soft computing, 2011, 19. Null steering of linear antenna arrays with use of modified. Thus in this paper the problem of forming nulls in the radiational pattern of threedimensional arrays is discussed.
Circular array with central element for smart antenna 2. Design of null steering vhflb phased array antenna with genetic algorithm a. Correction of faulty sensors in phased array radars using. Null steering and multibeams design by complex weight of antennas array with the use of apsoga. Nov 16, 2018 we design a grey wolf optimizer hybridized with an interior point algorithm to correct a faulty antenna array. But in large antenna arrays, there is always a possibility of failure of some. Antennas and propagation slide 3 chapter 4 5 antenna arrays 2 diversity redundant signals on multiple antennas reduce effects due to channel fading spatial multiplexing mimo. The performance of a nullsteering beamformer in correlated. Analysis and simulation of narrow band digitally beamformed phased array antenna with null steering ahmed najah jabbar, m. But in large antenna arrays, there is always a possibility of failure of some elements, which may degrade the radiation pattern with an increase in side lobe. Pdf null steering in failed antenna arrays researchgate.
But in large antenna arrays, there is always a possibility of failure of some elements, which may degrade the radiation pattern with an increase in side lobe level sll and removal of the. Adaptive antenna arrays have been used to form a timevarying beam pattern. Simple antennas can be combined to achieve desired directional effects. Ba adjusts the amplitude of each radiating element to minimise the total output power in the direction of the interfering signals. Element failure can degrade the antenna pattern so as to affect the beam steering and null steering. Null fill in the vertical plane is used to prevent this. We design a grey wolf optimizer hybridized with an interior point algorithm to correct a faulty antenna array. But in large antenna arrays, there is always a possibility of failure of some elements, which may degrade the radiation pattern with an increase in side lobe level sll. Pdf null steering in failed antenna arrays sachendra.
An antenna array element failure problem is one of the practical and. Research article correction of faulty sensors in phased array. Null steering of linear antenna arrays using a modified tabu search algorithm article pdf available in progress in electromagnetics research 331. Concentric circular array antenna null steering synthesis. The outer annular antenna is resonant in a higher order mode but forced to generate a right hand circularly. Individual antennas are called elements and the combination is an array. Towards a practical single element null steering antenna yuhsuan chen, fabian rothmaier, stanford university dennis akos, university of colorado at boulder sherman lo and per enge, stanford university biographies yuhsuan chen is a. Correction of failure in linear antenna arrays with greedy. Spatial null steering microstrip antenna array the mitre. Null steering figure 10, null depth vs null steering angle iv. Adaptive arrays can also reject unwanted interference signals by placing nulls in the direction of the interferers, which is known as beamnulling or null steering.
In the pso optimization process, to obtain the nulling performance in a failed antenna array the complex weight of each working element was considered as the optimization parameter. We consider the performance of a nullsteering adaptive beamformer in a distributed rayleigh fading environment. In the present paper, we have attempted to show the feasibility of using failed antenna array as a normal array and concentrated on the null steering and sll suppression issues. Sorry, we are unable to provide the full text but you may find it at the following locations. Null steering of adaptive beamforming using linear constraint. Restoring low sidelobe antenna patterns with failed elements. Null steering and multibeams design by complex weight of. Abstract in this paper, null steering to reject interference is studied for linear antenna arrays using bees algorithm ba. Concentric circular array antenna null steering synthesis by. Pdf null steering of linear antenna arrays using a modified. Zeroforcing or nullsteering precoding is a method of spatial signal processing by which the multiple antenna transmitter can null multiuser interference signals in wireless communications.
The signals from the antennas are combined or processed in order to achieve improved performance over that of a single antenna. Adaptive arrays can also reject unwanted interference signals by placing nulls in the direction of the interferers, which is known as beamnulling or nullsteering. In large antenna arrays possibility of getting faults for some of the radiating. An antenna array often called a phased array is a set of 2 or more antennas. Hfss models the array radiation pattern by applying an array factor to the single elements pattern9. It is common for techniques developed for phased antenna arrays to also be applicable in the temporal domain and thus section. In this work we have attempted to show the feasibility of using failed antenna array as a normal array and concentrated on the null steering and sll suppression issues. Null steering of adaptive beamforming using linear constraint minimum variance assisted by particle swarm optimization, dynamic mutated artificial immune system, and gravitational search algorithm. The possibility of failure of one or more sensors in the communication system can damage the radiation power pattern in terms of sidelobes, nulls and the communication become a dream. Correction of array failure using grey wolf optimizer. Recovery of failed element signal with a digitally beamforming. Moreover, adaptive beamforming is widely used in numerous communication systems for different purposes.
Read null steering of linear antenna arrays with use of modified touring ant colony optimization algorithm, international journal of rf and microwave computeraided engineering on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Towards a practical single element null steering antenna yuhsuan chen, fabian rothmaier, stanford university dennis akos, university of colorado at boulder sherman lo and per enge, stanford university biographies yuhsuan chen is a research engineer at the stanford gps laboratory. Recovery of failed element signal with a digitally. Pdf null steering of linear antenna arrays using a. Null steering of adaptive beamforming using linear. Antenna arrays phased arrays an antenna array often called a phased array is a set of 2 or more antennas. Concentric circular array antenna null steering synthesis by using modified hybrid ant colony system algorithm ali abdulhadi noaman 146 routes from the nest. Impact of phase and amplitude errors on array performance.
Towards a practical single element null steering antenna. The previous work on null steering in failed antenna arrays is presented in. Instead of analytical techniques an evolutionary optimization technique, viz. Design of null steering vhflb phased array antenna with. The elements in an array can be the same or different. Circular array with central element for smart antenna.
Proposed design studied arrays will be designed using hfss. Null steering of linear antenna arrays with use of. Restoring low sidelobe antenna patterns with failed. The need to separate cochannel signals by an antenna array arises in many situations. Abstract and applied analysis active and passive electronic components advances in agriculture advances in astronomy advances in civil engineering advances in condensed matter physics advances in fuzzy systems advances in hematology advances in high energy physics advances in humancomputer interaction advances in materials science and engineering advances in mathematical physics advances in. In active antenna array to obtain a desired radiation pattern with specified sidelobe level, null steering and beamforming is possible by controlling the current excitations of. Detection and correction of faulty patterns in antenna arrays have. The technique tries to restore the previous nulls pattern by using particle swarm optimization pso. Progress in electromagnetics research, pier 33, 167182, 2001 null steering of linear antenna arrays using a modified tabu search algorithm k. Chebyshev array pattern and the mask used for corresponding damaged pattern. But in large antenna arrays, there is always a possibility of failure of some elements, which may degrade th. Iv applies these techniques to arrays with no failed elements to modify either the taper loss or the sidelobe level.
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