Optimal Radiation Pattern Research Articles

Ear-to-Ear Propagation Model—Antenna Radiation Pattern Optimization and On-Body Far-Field Formulation

Ear-to-Ear Propagation Model—Antenna Radiation Pattern Optimization and On-Body Far-Field Formulation

Radiation Pattern Correction of Faulty Planar Phased Array using Genetic Algorithm

The probability of antenna array failure or malfunctioning cannot be ruled out, and hardware replacement of faulty elements is not always a viable solution. Therefore, academic and industrial interest in self-healing phased arrays are on the rise. In this work, the phase-only genetic algorithm (GA) optimization flow for the radiation pattern correction of a 4 × 4 phase faulty planar antenna array is proposed. Initially, a reference array pattern at the desired scan angle is generated. Then random phase faults are introduced across the 1 × 4 antenna elements in any one of 4 sub-arrays to produce maximum distortion in the reference radiation pattern of 4 × 4 planar array. The proposed GA re-computes the new excitation weights for the remaining non-faulty 3 sub-arrays to correct the overall radiation pattern of 4 × 4 array. This is achieved by calculating the array output power for reference and GA computed weights. The GA corrected patterns fairly follow the desired array patterns in terms of peak gain and reducing sidelobe levels for the desired scan angle. The efficiency of the optimized radiation patterns was evaluated in full-wave HFSS model and measurements validation. In this way, maintenance cost can be reduced with recovery of acceptable level of radiation pattern using software instead of physically replacing faulty antenna elements in the array.

An optimal concentric circular antenna array design using atomic orbital search for communication systems

Abstract In this study, optimum radiation patterns of Concentric Circular Antenna Arrays (CCAAs) are obtained by using the Atomic Orbital Search (AOS) algorithm for communication spectrum. Communication systems stands as a nascent technological innovation poised to revolutionize the landscape of wireless communication systems. It distinguishes itself through its hallmark features, notably an exceptionally high data transmission rate, expanded network capacity, minimal latency, and a commendable quality of service. The most important issue in wireless communication is a precision antenna array design. The success of this design depends on suppressing the maximum sidelobe levels (MSLs) values of the antenna in the far-field radiation region as much as possible. The AOS, which is a rapid and flexible search algorithm, is a novel physics-based algorithm. The amplitudes and inter-element spacing of CCAAs are optimally determined by utilizing AOS to the reduction of the MSLs. In this study, CCAAs with three and four rings are considered. The number of elements of these CCAAs has been determined as 4–6–8, 8–10–12 and 6–12–18–24. The radiation patterns obtained with AOS are compared with the results available in the literature and it is seen that the results of the AOS method are better.

An efficient linear and elliptical antenna array design using sail fish optimization

Abstract This article introduces an innovative approach to antenna array design, focusing on synthesizing the optimal radiation pattern for fifth-generation (5G) communication. The authors have designed a reliable linear and elliptical antenna array (EEA) of dipole elements by employing sailfish optimization (SFO). 5G technology promises transformative improvements in wireless communication with high data rates, expanded capacity, minimal latency, and exceptional service quality. The crux of 5G lies in the precision of antenna array design, aiming for an emission pattern with minimal side lobe levels (SLLs) and a narrow half-power beam width (HPBW). A narrower HPBW is essential for efficient long-range communication, whereas reducing the SLLs enhances signal clarity. The SFO optimizes the current excitation of each antenna element for reducing the mutual coupling effects and lowering the SLL and HPBW values in linear and EEAs. This paper uses the exact excitation to each element to show the linear antenna arrays (LAA) (10-, 16-element) design examples and EAA (8-, 12-, 20-element) structures. The LAA and EAA design examples obtained with the SFO algorithm establish the advancement in SLL suppression over the uniform antenna array and the methods proclaimed in the recent article.

A Rapid Optimization Scheme for the Simultaneous Optimization of S-Parameters and Radiation Patterns

A Rapid Optimization Scheme for the Simultaneous Optimization of S-Parameters and Radiation Patterns

Achievable Rate Maximization Pattern Design for Reconfigurable MIMO Antenna Array

Reconfigurable multiple-input multiple-output can provide performance gains over traditional MIMO by reshaping the channels, i.e., introducing more channel realizations. In this paper, we focus on the achievable rate maximization pattern design for reconfigurable MIMO systems. Firstly, we introduce the matrix representation of pattern reconfigurable MIMO (PR-MIMO), based on which a pattern design problem is formulated. To further reveal the effect of the radiation pattern on the wireless channel, we consider pattern design for both the single-pattern case where the optimized radiation pattern is the same for all the antenna elements, and the multi-pattern case where different antenna elements can adopt different radiation patterns. For the single-pattern case, we show that the pattern design is equivalent to a redistribution of gains among all scattering paths, and an eigenvalue optimization based solution is obtained. For the multi-pattern case, we propose a sequential optimization framework with manifold optimization and eigenvalue decomposition to obtain near-optimal solutions. Numerical results validate the superiority of PR-MIMO systems over traditional MIMO in terms of achievable rate, and also show the effectiveness of the proposed solutions.

A Compact Planar Wi-Fi Antenna with Optimized Radiation Patterns for Small UAV Applications

This paper proposes a compact planar Wi-Fi antenna with optimized radiation patterns for small uncrewed aerial vehicle (UAV) applications in both urban and open areas. It is suitable for mounting on the outermost side of the non-metallic wing of small UAVs. It has small dimensions of 16.5 mm (L) by 30.3 mm (W) by 1.6 mm (h), and the measured results of its prototype are in agreement with simulated data. Its impedance bandwidths over the two frequency ranges are 2.11 to 2.58 GHz and 5.06 to 7.5 GHz (S11≤-10 dB). At 5.8 GHz, it has stronger radiation below the small UAV to reduce interference from rare-use directions. Its maximum radiations, the directions of the maximum radiation in each elevation plane, are below the UAV and between 14° and 29° from the horizontal plane. At 2.4 GHz, it has quasi-omnidirectional radiation to ensure a stable link in all directions, and its maximum radiations are near the horizontal plane. The optimized radiation patterns at 5.8 and 2.4 GHz can provide more antenna gain when the small UAV flies farther in urban and open areas, respectively. In addition, it has good vertically polarized radiation for long-distance applications.

An optimal far field radiation pattern synthesis of mutually coupled antenna arrays

This article presents a precise approach for far-field radiation pattern (FFRP) correction of mutually coupled discrete dipole element (DDE) array of monopole antennas and concentric circular antenna array (CCAA) of dipole elements by employing the parametric assimilation technique (PAT). The effect of mutual coupling is a crucial part of any practical antenna array design issue. Various techniques have been suggested to calculate, compensate and reduce the mutual coupling effect during the last few decades. This article shows an exact method for mutual coupling inclusive corrected radiation pattern synthesis using PAT. The parameters of mutual impedance are calculated and assimilated with the values of the desired radiation pattern. The employed technique is cost-effective, less complex and easy to implement while achieving better performance for mutually coupled DDE array and CCAA synthesis. Grey wolf optimisation (GWO) is a state-of-the-art stochastic algorithm applied here to find the optimal values of the current amplitude excitation weights and the inter-element spacing between each element of the array in the DDE array and three-rings structure CCAA for the desired, uncorrected and corrected FFRP synthesis. Some well-established evolutionary optimisation techniques like particle swarm optimisation (PSO), differential evolution (DE) and social spider algorithm (SSA) are also employed in this article for the sake of comparison with the results achieved by using the GWO algorithm. Finally, the supremacy of GWO algorithm based design is demonstrated and validated by employing the 16-elements DDE array of monopole antennas and the three-ring CCAA of dipole elements.

A Fern Antipodal Vivaldi Antenna for Near-Field Microwave Imaging Medical Applications

This investigation presents an oval slot edge (OSE) antipodal Vivaldi antenna (AVA), hereinafter referred to as Fern AVA (FAVA), with an optimized radiation pattern. The use of OSE provided improvements in the antenna characteristics, especially regarding a lower frequency limit reduction, an increase in the main lobe (ML) gain, and the sidelobe level (SLL) reduction. Those contrasting characteristics are simultaneously obtained through the class of the Palm Tree antennas. The proposed FAVA at 1.5 GHz shows an improved gain of 6.66 dB, −12.9 dB of SLL, and 0° of ML squint (MLS), in contrast with 4.41 dB of gain, −4.5 dB of SLL, and 4° of MLS in the conventional AVA. For the FAVA, the notches in an elliptical shape, in addition to mitigating the SLL, direct the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}$ </tex-math></inline-formula> -fields distributions toward the ML, which categorizes it into the same class as the Palm Tree Vivaldi Antenna. To study the performance of the proposed antenna for medical applications of near-field microwave imaging, a conceptual proof was performed, thus obtaining the microwave image of a Child Head Phantom, homogeneous, and semirealistic, being possible to detect a brain tumor.

Planar Array Failed Element(s) Radiation Pattern Correction: A Comparison

Phased arrays are widely used in different fields, such as broadcasting, radar, optics, and space communications. The principle of phased arrays is to generate a directed signal from a large number of antennas to be steered at any desired angle. This, however, increases the probability of defective elements in an array. Faulty elements in an array cause asymmetry and result in increased sidelobe levels which rigorously distort the radiation pattern. Increased sidelobe radiation wastes energy and can cause interference by radiating and receiving signals in unintended directions. Therefore, it is necessary to find a method that can provide accuracy in the radiation pattern transmitted or received in the presence of failed element(s) in an array. This paper compares the few available optimization methods, namely, simulated annealing (SA), Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Pattern Search (PS) methods. For each method, various types of failures were examined, and the most suitable techniques to recover the far-field radiation are recommended. The optimization is then carried out by selecting the optimal weights of the remaining working elements in the planar array. The optimized radiation pattern’s efficiency was evaluated by comparing the Signal to Noise Ratio (SNR) value of the optimized radiation with reference and failed radiation patterns. The PSO method showed a better performance compared to all the other methods in reducing the failed radiation pattern’s SNR value. In various types of failure tests, this method reduced the failed radiation pattern’s SNR from 1 to 10 dB. This method also successfully produced a radiation pattern that closely matches the reference pattern before any failed element(s) are presented in the array. The life cycle of a planar array system with faulty elements can be increased by optimizing the remaining active elements in the array with the PSO method. It also reduces the cost of restoring and replacing the failed elements in an array regularly. This approach also prevents near-field measurement that requires complicated processes using costly equipment.

Improved Salp swarm optimization based circular arrays in presence of mutual coupling

This article presents optimization of circular arrays with mutual coupling effect (MCE) using newly developed algorithm, Improved Salp swarm optimization (ISSO). ISSO is employed to achieve optimum radiation patterns of circular array (CA), and concentric circular array (CCA). The radiation patterns illustrate directive main beams with various outcomes, such as suppressed maximum side lobe level, deep nulls placed in specific directions, and maximum possible directivity. The main beams of the patterns are made narrow and directive by maintaining the first null beam widths equal or less than that of uniform CA and CCA throughout the optimization process. The above performance parameters are obtained by optimizing the parameters like excitation currents, positions, and phases of the array elements, and number of array elements using a multi-objective optimization function (OF). The OF is formulated by considering the performance parameters and MCE. The outcomes are analyzed for eight different optimization case studies of CA and CCA. The results of the CA and CAA using ISSO are compared with that of other optimization methods found in the literature. The performance parameters of the case studies considered indicate that CA configurations using ISSO offer improved performance relative to uniform arrays and the configurations achieved using other methods of optimization.

Optimal radiation pattern synthesis of mutually coupled antenna array using an efficient compensation method

Optimal radiation pattern synthesis of mutually coupled antenna array using an efficient compensation method

Rabid Euclidean direction search algorithm for various adaptive array geometries

One of the exciting technologies used to meet the increasing demand for wireless communication services is a smart antenna. A smart antenna is basically confirmed by an array of antennas and a digital beamformer unit through which cellular base station can direct the beam toward the desired user and set nulls toward interfering users. In this paper, different array configurations (linear, circular, and planer) with the REDS algorithm are implemented in the digital beam-forming unit. The wireless system performance is investigated to check the smart antenna potentials assuming Rayleigh fading channel environment beside the AWGN channel. Results show how the REDS algorithm offers a significant improvement through antenna radiation pattern optimization, sidelobe level, and interference reduction, and also the RDES algorithm proves fast convergence with minimum MSE and better sidelobe level reduction comparing with other algorithms.

Optimization of Beamforming in Subarray Antennas Using Firefly Algorithm

The subarray antenna techniques are much focused for flexible beamforming in envisioned smart antenna applications. The aim of this subarray arrangement of antenna elements is greatly motivated by bandwidth enhancement and interference minimization in the upcoming 5G next generation networks infrastructure. The optimization is required for effective placement of nulls in the desired direction of interferes from known sensed and verified disturbance angles. In this three dimensional radiation pattern optimization, the number of phase shift elements and constructive values for pointing focused beam and destructive strength in the obstacles is crucial. In this paper we proposed a firefly algorithm for dynamic management of the radiation pattern. It is possible with the optimization of the weight parameters of the subarray antenna. From the given Direction of Arrival we investigate the possibilities of deep placing of nulls is simulated and analyzed with the antenna parameters.

The Concentric Elliptical Antenna Array Patterns Synthesis Using Marine Predators Algorithm

In this paper, the pattern synthesis of concentric elliptical antenna arrays (CEAAs) for effective antenna design is presented. The current amplitudes and angular positions values of the CEAA elements are optimally found by using the Marine Predators Algorithm (MPA) in order to obtain the optimum radiation pattern. The MPA method is a novel nature-based optimization algorithm that is inspired by ocean predators foraging strategy. The antenna arrays with reduced maximum side lobe levels (MSL) and narrowed half power beam widths (HPBW) are an efficient antenna with optimum radiation pattern to suppress interference and increase directionality. In addition, CEAAs with different numbers of elements are examined to show the flexibility and performance of the proposed algorithm in this study. For 18-element CEAA, MPA obtained the HPBW between 29.18° and 31.34°, and MSL between − 20.70 and − 25.89 dB. For 30-element CEAA, the optimum values of HPBW are between 20.13° and 21.38°, and the optimum values of MSL are between − 18.90 and − 20.50 dB. The results of pattern synthesis obtained by MPA are compared with other metaheuristic optimization methods, and it is seen that the results of the proposed method are generally better.

Deep Neural Network Modeling of Different Antenna Arrays; Analysis, Evaluation, and Application

Array signal processing and systems brings merit for synthesizing the optimal radiation pattern for steering the mainbeam in the direction of interest as well as suppressing interference signals in the direction of not interest while preserving the beamwidth. In this study, we have rigorously represented the deep neural network (DNN) modeling of the different geometries of the antenna arrays in three scenarios. In the first scenario, we briefly review and highlight some of the research methodologies and involved problems of the DNN modeling. The ultimate validation and verification of the DNN modeling have been fulfilled by estimating the DNN outputs and obtaining the radiation patterns of the different array geometries. In the second scenario, we have employed the three concepts of mean squared error (MSE), Shannon error entropy minimization (EEM), and bit error rate (BER) for the performance evaluation and validation of implementing the proposed DNN models for the different array geometries. The concept of Shannon error entropy can be extended to optimize the nonlinear and non-Gaussian problems. In the third scenario, the application of the DNN models in the direction of arrival (DoA) estimation has been analogously represented among the different array geometries.

An optimal compact time-modulated circular antenna array synthesis using krill herd optimization

In this paper, an optimal far-field radiation pattern synthesis by using time modulation technique is carried out for a compact circular antenna array (CAA) design using a stochastic optimization method called krill herd (KH) optimization. A compact antenna array is achieved by reducing the inter-element spacing between the array elements, which leads to the miniaturization of the size of the array. On the other hand, an improved far-field radiation characteristic is achieved with a low side lobe level (SLL) and narrow first null beam width (FNBW). A low SLL is an essential requirement to reduce the interference with the other systems operating in the same frequency band. A narrow FNBW is necessary to obtain a high directivity. In time modulation technique, ‘time’ has the most significant role. It is considered the fourth-dimensional parameter, which plays the role of an additional degree of freedom to achieve an improved radiation pattern. The time-modulated antenna array (TMAA) radiates at various harmonic frequencies for the periodic switching time sequence. In this paper, the generation of the radiation pattern at the fundamental/central frequency only is considered. The KH algorithm is a flexible and robust search algorithm. It is applied here to find out the optimum sets of switching on-time duration for each array element and to determine the optimum inter-element separation between two array elements of the 20- and 36-element time-modulated circular antenna array (TMCAA). Particle swarm optimization (PSO) and differential evolution (DE) optimization techniques are also individually applied for the same design purpose to prove the superiority of the KH algorithm–based design. Finally, statistical analysis is performed to ensure the significance of the numerical results.

Over-the-Air Calibration of Active Antenna Arrays Using Multisine

A novel over-the-air (OTA) beamforming calibration procedure is proposed, which can be applied to different types of multiple-input multiple-output (MIMO) transmitting antennas. The method consists of using two tones on each antenna element, the main tone, and the tickle tone. The latter one operates in a different frequency for each antenna element and is used to obtain the optimum phase that needs to be set for each element to generate a beam in the desired direction, at the main tone frequency. The novel method was applied to linear, planar, 3-D antennas, and noncollocated multiantennas to validate its applicability to different antenna types. Line-of-Sight (LOS) and non-LOS experimental results demonstrate that the method can be used to retrieve the required phase to fully control the antenna radiation pattern. An optimum radiation pattern and lowest error vector magnitude (EVM) can be achieved even under high multipath effects/non-LOS conditions. A comparison between the performance and the application of the array factor (AF) theory is presented for practical indoor scenarios, demonstrating the effectiveness of the method. It is demonstrated that the method may be an alternative to the calibration of nonstandard MIMO antennas, where the AF computation is complex or not possible.

Theoretical Derivation and Optimization Verification of BER for Indoor SWIPT Environments

Symmetrical antenna array is useful for omni bearing beamforming adjustment with multiple receivers. Beam-forming techniques using evolution algorithms have been studied for multi-user resource allocation in simultaneous wireless information and power transfer (SWIPT) systems. In a high-capacity broadband communication system there are many users with wearable devices. A transmitter provides simultaneous wireless information and power to a particular receiver, and the other receivers harvest energy from the radio frequency while being idle. In addition, the ray bounce tracking method is used to estimate the multi-path channel, and the Fourier method is used to perform the time domain conversion. A simple method for reducing the frequency selective effort of the multiple channels using the feed line length instead of the digital phase shifts is proposed. The feed line length and excitation current of the transmitting antennas are adjusted to maximize the energy harvest efficiency under the bit error rate (BER) constraint. We use the time-domain multipath signal to calculate the BER, which includes the inter symbol interference for the wideband system. In addition, we use multi-objective function for optimization. To the best of our knowledge, resource allocation algorithms for this problem have not been reported in the literature. The optimal radiation patterns are synthesized by the asynchronous particle swarm optimization (APSO) and self-adaptive dynamic differential evolution (SADDE) algorithms. Both APSO and SADDE can form good patterns for the receiver for energy harvesting. However, APSO has a faster convergence speed than SADDE.

An optimal circular antenna array design considering the mutual coupling employing ant lion optimization

AbstractThis paper presents an efficient approach for the design of a non-uniform single ring circular antenna array (CAA) for the synthesis of the optimal far-field radiation pattern. A recently proposed meta-heuristic-based optimization technique known as ant lion optimization (ALO) is applied in this paper to determine the optimum set of current amplitude excitation weights and the inter-element distance among the array elements to reduce the side lobe level (SLL) and 3-dB beam width considering the mutual coupling effect. The results achieved by employing the ALO algorithm are compared with the uniform radiation pattern and with those of the recently reported literature containing equal sets of elements to prove the superiority of ALO algorithm. Three different design examples of 8, 10, and 12 elements CAA are presented, and their performances are compared to illustrate the capability of the ALO algorithm-based approach over those of the recently reported literature.