Rapid Design Closure of Linear Microstrip Antenna Array Apertures Using Response Features

본 논문에서는 선형 위상 배열 안테나 패턴 합성 문제에서, 주 빔 패턴 양쪽에 임의로 설정한 비대칭 sidelobe 레벨(SLL)들을 만족시키는 안테나 소자 가중치들을 계산하는 방법을 새로이 제안한다. 소자 가중치들을 배열인자로부터 직접 최적화하는 기존의 방법들과는 달리, 이 방법은 배열 인자를 표현하는 Schelkunoff 다항식에 내재된 복소근의 최적 섭동에 기본을 둔다. 제안한 방법으로부터 여러 개의 jammer들의 방향으로 다중 nulling도 가능하며, 이는 각 jamming 방향에 대응하는 복소근들만의 독립적인 섭동에 의해 이루어진다. 따라서 해 공간차원의 적절한 감소에 의해 수치적 절차가 간소화될 수 있다. 또한 배열 소자들의 복소 가중치들은 최적 섭동된 복소근들을 Schelkunoff 다항식에 대입함으로써 쉽게 계산된다. 몇 가지 예를 들어 검토하고, 도출된 가중치들을 배열 인자 방정식에 대입함으로써 타당성을 수치적으로 검증한다. This paper newly proposes a methodology towards computing antenna element weights which are satisfying asymmetric sidelobe levels(SLLs) specified arbitrarily on both sides of the main beam pattern, in the linear phased array antenna pattern synthesis problem. Opposite to the conventional methods in which the element weights are directly optimized from the array factor, this method is based on the optimum perturbations of complex roots inherent to the Schelkunoff's polynomial form which is described for the array factor. From the proposed methodology, the capability of nulling the directions of multiple jammers is also possible by independently perturbing only the complex roots corresponding to each jamming direction, hence allowing an enhancement of the simplicity of the numerical procedure by means of a proper reduction of the dimension of the solution space. The complex weights over the array are then easily computed by substituting the optimally perturbed complex roots to the Schelkunoff's polynomial. Some examples are examined and numerically verified by substituting the extracted weights into the array factor equation.

This article details about the method of controlling Side-Lobe-Level (SLL) in the radiation pattern of mutually coupled symmetrical linear dipole antenna array in a proper direction. There are several conventional numerical and analytical methods to compensate the effect of mutual coupling, but to get better performance on linear dipole antenna arrays, an effective optimization technique is implemented; i.e.; Craziness based Particle Swarm Optimization (CRPSO). This technique provides solution for the nonlinear array factor equation which comprised of general n-dimensional components including current excitation of each antenna array element and inter-element spacing. In addition, analysis of comparative studies is discussed with the aid of calculating driving point impedance of antenna array for optimum inter-element spacing. An adequate amount of improvement in radiation pattern is achieved by reducing the unwanted SLL. Empirical study on the result is analyzed both quantitatively and qualitatively.

This paper proposes a novel high gain and low sidelobe level (SLL) linear microstrip array antenna for outdoor WLAN applications. The antenna consists of two main parts, which are a linear array and a reflector. The linear array comprises of 10 elements; those have been designed on Rogers RT/Duroid 5870tm with the dimensions of 422×100×10.15 mm3. To gain low SLLs, a series fed network was designed to have the output signals being proportional to the Chebyshev distributions (with preset SLL of -30 dB). Furthermore, Yagi antenna theory has been applied by adding directors above every single element to increase the directivity of the single element. The reflector has been constructed at the back of the proposed structure. Simulation results show that the array can provide high gain of 17.5 dBi and a low SLL of -26 dB. A prototype has been fabricated and measured. Good agreements between simulation and measurement data have been obtained.

This research has proposed the iterative genetic algorithm (GA) optimization scheme to synthesize the radiation pattern of an aperiodic (nonuniform) linear array antenna. The aim of the iterative optimization is to achieve a radiation pattern with a side lobe level (SLL) of ≤−20 dB. In the optimization, the proposed scheme iteratively optimizes the array range (spacing) and the number of array elements, whereby the array element with the lowest absolute complex weight coefficient is first removed and then the second lowest and so on. The removal (the element reduction) is terminated once the SLL is greater than −20 dB (>−20 dB) and the elemental increment mechanism is triggered. The results indicate that the proposed iterative GA optimization scheme is applicable to the nonuniform linear array antenna and also is capable of synthesizing the radiation pattern with SLL ≤ −20 dB.

This paper proposes the design of linear microstrip antenna and array using L-probe feeding technique. L- probe is an attractive feed technique, which can be used to avoid the use of electrically thick substrates. This feed technique is used to design antenna array with high gain. A 15-element linear array is designed to give bandwidth from 5.71 -5.91 GHz (|S 11 | < -10 dB) with peak gain of 18.9 dBi with stable radiation pattern over the bandwidth. The side lobe level is -14.3 dB at 5.86GHz.

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.

This paper presents a linear phased array antenna with beam steering capability designed for WiFi and LTE mobile standards. The proposed antenna array utilizes 4 elements of patch antenna arranged in a flat configuration. The antenna element used in the array exhibits dual band characteristic covering 2 wide frequency bands; 2.35 GHz to 2.8 GHz (lower band) and 5 GHz to 5.5 GHz (upper band). To excite dual resonances, a rectangular ring slot was cut in the ground plane of the rectangular patch. The upper patch acts as the feeding element for the rectangular ring slot for lower band operation and as a radiator at the upper frequency band. The simulation results show a bi-directional radiation pattern at the lower frequency band and unidirectional at the upper band. By varying the phase of the individual antenna elements, the main beam of the proposed linear array can be steered to a range of ±40° for the lower band and ±22° for the upper band with side lobe level (SLL) and half-power beam width (HPBW) less than −7 dBi and 43° respectively. The array is intended to be fed by a corporate feeding network using three wideband 3-port Wilkinson power dividers. A FR4 (1.6 mm) is used as the antenna substrate and the feeding element. The overall size of the proposed array and the feeding element is 155 mm × 35 mm × 1.6 mm and 155 mm × 83 mm × 1.6 mm respectively. The designs and simulations have been carried out using CST Microwave Studio. The presented array antenna can be particularly applied to small and portable mobile base stations.

The pattern synthesis technique of antenna arrays has a wide range of applications in radar and communication systems, which is an important research direction in the field of smart antennas. In order to improve the optimization performance of pattern synthesis of linear antenna arrays, an optimization method based on the Modified RIME Optimization Algorithm (MRIME) is proposed. RIME is a new heuristic algorithm inspired by the condensation process of frost ice in nature, which has a unique update mechanism with strong convergence as well as randomization. In the present work, MRIME is used for optimal pattern synthesis of a linear antenna array (LAA). One part of the present study is to optimize the side lobe level by optimizing the antenna current amplitude while maintaining a uniform spacing; the other part is to optimize the antenna position while assuming a uniform excitation in the synthesis of a sparse LAA, where constraints are imposed on the spacing of the array elements and aperture length, and suppression of the side lobe level with the position of the zeros in the specified direction is also achieved. In this article, simulation experiments for uniform linear arrays as well as sparse linear arrays are presented in detail, and the results show that the MRIME optimization algorithm outperforms most of the existing evolutionary classes of optimization algorithms in optimizing the side lobe level. This illustrates the potential of utilizing the MRIME optimization algorithm for antenna arrays and various other electromagnetism-related challenges.

In this research paper, quantum particle swarm optimization (QPSO) algorithm, an algorithm founded on the basic theory of particle cluster and properties of quantum mechanics, has been introduced for design of uniformly spaced scanned linear array antennas with definite value of sidelobe level (SLL), first null beam width (FNBW), and broad null depth. An effort is made such that these parameters are made equal to their related specific values. This is usually done by changing excitation current amplitude of the elements. The expression of array factor is derived by using the property of linear array antennas. One example has been presented with 35 isotropic antennas. Generated Pattern is scanned to an angle of 30°. The obtained results have shown that this technique is able to find required value of SLL, FNBW, and wide null depth. Although, the proposed method is developed and applied to a linear array of isotropic antennas; however, the principle can easily be applied to other types of arrays.

The purpose of this paper is to introduce the concept of fractals and its use in antenna arrays for obtaining multiband property. One type of fractals namely, Cantor set is investigated. Cantor set is used in linear array antenna design. Therefore, this array know fractal Cantor linear array antenna. A comparison with conventional non-fractal linear array antenna is made regarding the beamwidth, directivity, and side lobe level. MATLAB programming language version 7.2 (R2006a) is used to simulate the fractal and conventional non-fractal linear array antenna and their radiation pattern.

A systematic approach to sidelobe reduction of broadside linear antenna arrays using corporate feeds implementing non-uniform excitation is proposed. Only the corporate feeds that consist of equal-power split T-junctions, i.e., the simplest power dividers, are considered. First, for a given particular array aperture, candidate feeds (excitation sets) are searched among excitation sets which might energize the aperture. The search is performed over all realizable excitations using the array factor and the model of excitation amplitudes due to power distribution within the feed. At the second stage, an excitation that provides reduced sidelobes and simple routing is implemented as a microstrip corporate feed. Finally, the entire antenna-feed circuit is tuned and validated using numerical optimization and discrete electromagnetic simulations at the high-fidelity level of description. Our approach offers flexibility in design of linear antenna arrays without introducing extra hardware complications. A case study of a twelve-element microstrip array-feed circuit explains and demonstrates our approach.

Researches of dependency of aperture efficient of Dolph-Chebyshev antenna arrays on different lengths and random side-lobe levels are carried out in this work. Dependency of aperture efficiency on specified side-lobe level and on the length of antenna array is described. Analysis of the value of aperture efficiency for given side-lobe levels and the length of antenna array is done. Conclusions and recommendations for use of Dolph-Chebyshev amplitude distribution for linear antenna arrays with optimal length by the criterion of maximum aperture efficiency for given side-lobe levels according to the results are given in article. From the results we can see that for higher levels of side-lobes (more than − 30dB) for getting maximum possible value of aperture efficiency optimal length is highly dependent on side-lobe levels. This length is a few wavelengths. Optimal length of antenna array for side-lobe level less than −30dB is hundreds of wavelength. It is weakly dependent on side lobe levels.

A simple feed network is introduced for a linear microstrip array antenna. The antenna structure consists of two layers. The radiating microstrip patches are placed on the top surface of the upper layer, while the bottom layer is used to feed the radiating elements through the slots on the conducting microstrip line between the upper and lower layers. The resultant array antenna is relatively simple, and the feed loss can be minimized. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 25–27, 1999.

Analytical array polynomial method for linear antenna arrays with phase-only control

This work is concerned with the methodology for improvement of the radiation pattern performance and eliminating the effect of unwanted interference of symmetric time modulated linear antenna array (STMLAA) in the predefined direction. This is achieved using evolutionary technique called Novel Particle Swarm Optimization with Wavelet Mutation (NPSOWM) for various application specific optimization like SLL only reduction, dual broad null and multiple broad null optimization. The optimized results obtained by using NPSOWM are validated by CST-MWS by captivating practical elements of dipole antenna and its array configuration. The numerical results show the effect of the particular (practical) antenna on the array. Various examples have taken for this purpose. A set of 16-element antenna array have designed for SLL only reduction. 16-, 32-, and 64-element STMLAA for incorporating the dual broad nulls in the angular range from 400 to 700 over the elevation plane. A set of 24-, 30-, and 32-element antenna array have occupied for multiple broad nulls. The strength of the adopted algorithm is tested for different number of array antenna configuration, which establish the efficacy of the optimization technique NPSOWM adopted for achieving the interference cancellation in the predefined direction and performance improvement of the antenna array such as simultaneous improvements of broad nulls (BNs), sidelobe level (SLL), sideband level (SBL), and the directivity. From the simulated results it is clear that NPSOWM can perform better than that of un-optimized linear antenna array with respect to BNs, SLL, and SBLs and Directivity.