Phase-Only Nulling With Limited Number of Controllable Elements

Abdulqader, Ahmed Jameel; Mohammed, Jafar Ramadhan; Thaher, and Raad H.

doi:10.2528/pierc20010203

Cited by 14 publications

(12 citation statements)

References 20 publications

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“…Figure 1 shows the right side of the general structure of the standard linear array that consists of N elements, then the standard array factor (AF) in the far field can be written as [3]:…”

Section: Model Of Multi-objective Function With Thinned Methodsmentioning

confidence: 99%

“…The elimination of radiating components from a regularly spaced or cyclic array to generate the desired radiation pattern is referred to as array thinning. The main objective of thinning is to reduce the weight, cost, energy consumption, and execution time of the algorithm [1][2][3]. The locations of the radiating elements will be determined in thinning array synthesis, and each element will have two states: "ON component" or "active state" (when the element is supplied) and "OFF component" or "passive state" (when the elements are passively removed or not fed by the source) [4].…”

Section: Introductionmentioning

confidence: 99%

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A Multi-objective Array Pattern Optimization via Thinning Approach

Abdulqader¹,

Mahmood²,

Ali³

2022

PIER C

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In this paper, the possibility of synthesizing a linear antenna array for multiple objectives with the thinning approach is demonstrated. The thinning space is constrained to three cases (side, central, and random) parts instead of a fully filled linear array. In the case of the side part, a set of elements located on both edges of the array are removed with the optimized elements close to the center remaining unchanged. As in the case of the central part, only a set of elements close to the center are removed. In the case of a random selection of elements, the cancellation process is carried out randomly within the sides and the center. Since the amplitude weights of the elements located on the edges of the array have a small amplitude excitation, the method of side thinning gives better results than the other two cases. Moreover, in cases of side and random thinning, the last element of each side is excluded from the thinning process to maintain the aperture size. The convex algorithm (CA) is used to perform such thinning optimization. CA optimization efficiently computes a multi-objective function in coordination with the thinned array technique, such as preserving the main beamwidth in all cases with the reduction of sidelobe levels, generating one or more nulls, and steering the main beam in a certain direction. The simulation results, in all cases, show that 30%-40% of the array elements can be turned off with achieving a multi-objective radiation pattern.

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Section: Model Of Multi-objective Function With Thinned Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Multi-objective Array Pattern Optimization via Thinning Approach

Abdulqader¹,

Mahmood²,

Ali³

2022

PIER C

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“…In [8], the authors suggested to adjust only the amplitude excitations of the array elements instead of both amplitude and phase excitations to simplify the design implementation of the array feeding network and reduce the number of the optimized variables. Other researchers suggested the use of the phase-only excitation method [9] to optimize the planar array elements. Recently, efficient methods for linear [10][11][12][13][14] and planar arrays [15][16][17][18] were suggested.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Performance Improvement of Planar Antenna Arrays With Optimized Square Rings for Massive MIMO Applications

Mohammed,

Khamees

2024

J. Electron. Electric. Eng.

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The power pattern of the conventional fully optimized planar arrays can be properly reshaped according to the required user-defined constraints. However, the practical implementation of such fully optimized large planar arrays is complex and expensive. This paper introduces a new and efficient technique that is capable of providing better performance and almost the same power pattern shapes as that of the conventional fully optimized planar arrays by optimally adjusting the element amplitude and phase excitations of the outer-square rings instead of all elements' excitations. The proposed technique starts with a massive fully planar array then divides it into two contiguous sub-planar arrays which are both symmetric about the original array center. The elements excitation amplitudes or phases of the outer sub-planar array are only adjusted to form the desired power pattern shapes, while the amplitudes or phases of the central sub-planar array elements which have usually higher weights than the outer elements are made constants (i.e., they made ones for the case of amplitude-only control and zeros for the phase-only control). The results demonstrate the capability of the proposed planar array to form the required power patterns with far less number of the adjustable elements.

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“…Such operation results in a significant improvement in the output signal-to-interference plus noise ratio (SINR). Historically, all the element excitations have had their amplitude weighting [1] and/or phase weighting [2,3] adjusted in order to achieve null steering [4] or sidelobe level (SLL) reduction [5,6]. Other methods use two edge elements control [7] or a restricted subset of the array elements [8].…”

Section: Introductionmentioning

confidence: 99%

Scanned Antenna Arrays with Random Deactivated Elements

Yaseen,

Mohammed

2024

PIER Letters

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Usually inactive or also known as thinned elements are used to simplify the array design complexity by turning off some of the active elements in uniformly filled arrays. Consequently, the far-field radiation characteristics such as sidelobe level, beamwidth, and directivity may be negatively changed if no optimizer is used. Further, these radiation characteristics may be unavoidably deteriorated when the main beam is scanned to new directions other than the referenced broadside direction. In this paper, an efficient optimization method based on the genetic algorithm and a dynamic deactivation method is proposed to randomly deactivate a number of array elements to minimize the peak sidelobe level and at the same time maintain the array directivity undistorted, while scanning the main beam. The deactivation method chooses optimally the suitable number of elements and their locations that need to be deactivated such that the resulting radiation characteristics positively change according to the specified cost function. Also, the proposed scanned array uses binary coefficients to activate and deactivate the array elements, thus, the feeding network of the proposed array is very simple, and it can be easily implemented in practice. Through extensive simulation results, we show that the proposed optimization method has good performance under wide range of scanned main beam directions. It is also found that the number of deactivation elements (i.e., the optimization variables) increases with larger scan angle.

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Phase-Only Nulling With Limited Number of Controllable Elements

Cited by 14 publications

References 20 publications

A Multi-objective Array Pattern Optimization via Thinning Approach

A Multi-objective Array Pattern Optimization via Thinning Approach

Analysis of Performance Improvement of Planar Antenna Arrays With Optimized Square Rings for Massive MIMO Applications

Scanned Antenna Arrays with Random Deactivated Elements

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