Antenna arrays technologies for advanced wireless systems

Iskander, Magdy F.; Kim, Wayne; Bell, J.M.; Çelik, Nuri; Yun, Zhengqing; Youn, Hyoung-sun

doi:10.1109/comcas.2009.5385955

Cited by 5 publications

(2 citation statements)

References 11 publications

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“…Phased array radar, in which the main beam and null are pointed toward the expected direction and beam scanning is realized by weighting the amplitudes and phases of each array element [ 1 , 2 ], plays an important role in gain control, resolution enhancement, and anti-jamming maximization [ 3 , 4 ] and has been widely used in radar, navigation, sonar, and communication [ 5 , 6 , 7 , 8 ]. Beamforming, which is one of the key techniques for phased array radar, allows users to adjust the direction of the main beam and nulls and, therefore, perform target detection, tracking, and interference suppression [ 4 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

IDBD-Based Beamforming Algorithm for Improving the Performance of Phased Array Radar in Nonstationary Environments

Wang

Chen

Wang

2023

Sensors

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Adaptive array processing technology for a phased array radar is usually based on the assumption of a stationary environment; however, in real-world scenarios, nonstationary interference and noise deteriorate the performance of the traditional gradient descent algorithm, in which the learning rate of the tap weights is fixed, leading to errors in the beam pattern and a reduced output signal-to-noise ratio (SNR). In this paper, we use the incremental delta-bar-delta (IDBD) algorithm, which has been widely used for system identification problems in nonstationary environments, to control the time-varying learning rates of the tap weights. The designed iteration formula for the learning rate ensures that the tap weights adaptively track the Wiener solution. The results of numerical simulations show that in a nonstationary environment, the traditional gradient descent algorithm with a fixed learning rate has a distorted beam pattern and reduced output SNR; however, the IDBD-based beamforming algorithm, in which a secondary control mechanism is used to adaptively update the learning rates, showed a similar beam pattern and output SNR to a traditional beamformer in a Gaussian white noise background; that is, the main beam and null satisfied the pointing constraints, and the optimal output SNR was obtained. Although the proposed algorithm contains a matrix inversion operation, which has considerable computational complexity, this operation could be replaced by the Levinson–Durbin iteration due to the Toeplitz characteristic of the matrix; therefore, the computational complexity could be decreased to O(n), so additional computing resources are not required. Moreover, according to some intuitive interpretations, the reliability and stability of the algorithm are guaranteed.

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Section: Introductionmentioning

confidence: 99%

IDBD-Based Beamforming Algorithm for Improving the Performance of Phased Array Radar in Nonstationary Environments

Wang

Chen

Wang

2023

Sensors

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“…The downconverter and the ADC are built in a custom made computer case for portability and ruggedness. Further details of the prototype and the calibration procedure are published in [6].…”

Section: Introductionmentioning

confidence: 99%

Experimental evaluation of the Hybrid Smart Antenna system with directional array elements

Çelik

Iskander

Emrick

et al. 2009

2009 IEEE Antennas and Propagation Society International Symposium

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The Hybrid Smart Antenna Algorithm (HSAA) relies on elimination of the array elements with the smallest received signal powers in the beamforming process in order to improve the computational efficiency, and reduce the hardware cost. Earlier computer simulations [1] suggested that it is possible to further suppress the sidelobes by employing directive array elements. In this paper we present the results of experimental verification of this observation. Specifically, an 8-element array consisting of 30°half power beamwidth (HPBW) Yagi-Uda antennas is used with the HSAA. Although the directivity of the array elements is heavily affected by the mutual coupling effects, a significant decrease in the sidelobe levels is observed thus confIrming the simulation results. This experimental effort further confIrmed other advantages of the HSAA approach. It is shown that the exact direction of arrival (DOA) is determined by selecting only 2 elements out of the 8 possible with the Yagi-Uda elements while the array of omni-directional dipole elements required at least 5 out of 8 elements. The experimental procedure is described and comparison with simulation results is presented. I. INTRODUCTIONBy sampling the transmitted signal several times in space, and coherently combining them, smart antenna receiver systems provide extended communication ranges, higher data rates, and larger capacities. As expected, the number of elements in the array is the main determinant of the smart antenna system performance, and there is a linear relationship between the quality of the smart antenna system performance and the number of elements on the array. However, the computational complexity of the array increases with the second power of the number of array elements in addition to the linear increase in the hardware cost [1].

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Design, optimization, and verification of an antenna array for the 60 GHz Hybrid Smart Antenna System

Çelik¹,

Iskander²

2010

2010 IEEE Antennas and Propagation Society International Symposium

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Antenna arrays technologies for advanced wireless systems

Cited by 5 publications

References 11 publications

IDBD-Based Beamforming Algorithm for Improving the Performance of Phased Array Radar in Nonstationary Environments

IDBD-Based Beamforming Algorithm for Improving the Performance of Phased Array Radar in Nonstationary Environments

Experimental evaluation of the Hybrid Smart Antenna system with directional array elements

Design, optimization, and verification of an antenna array for the 60 GHz Hybrid Smart Antenna System

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