Low Sidelobe Level Research Articles

Efficient side lobe level reduction technique for planar antenna arrays

This paper presents a novel array synthesis technique based on the virtual antenna array (VAA) concept for side lobe level (SLL) reduction of uniform planar antenna arrays (UPAA). The VAA decomposes the (M×N) UPAA into vertical and horizontal uniform linear antenna arrays (V–ULAA and H–ULAA) consisting of M and N antenna elements, respectively. The V-ULAA and H-ULAA are positioned perpendicularly and closely enough apart to form a new (M+N) virtual UPAA. Consequently, the number of antenna elements is significantly reduced, which in turn minimizes the computational complexity and signal processing time required to synthesize the desired radiation pattern. Therefore, instead of reducing the SLL of the entire UPAA, we simply reduce the SLL of each ULAA using the well-known hybrid Method of Moments/Genetic Algorithm (MoM/GA) array synthesis technique, which adjusts both the excitation coefficients and element spacings to achieve low SLL. The MoM/GA results in non-uniform V-LAA and H-LAA having two non-uniform excitation vectors AV and AH, respectively, and much lower SLLs than the corresponding V-ULAA and H-ULAA. Finally, the synthesized excitation vectors AV and AH are used to synthesize either the virtual (M+N) planar antenna array (V-PAA) or the physical (M×N)PAA with more than two-fold reductions in the SLL.

Low Sidelobe Level, High-Gain Patch Antennas Operating at Higher-Order Modes

Low Sidelobe Level, High-Gain Patch Antennas Operating at Higher-Order Modes

Marine predator’s algorithm-based linear and elliptical antenna array design for 5G communication

The highly efficient linear and elliptical antenna array design presented in this article is intended to synthesize far-field radiation patterns for 5G communication. The objective is to achieve the best possible radiation pattern, which includes a lower side lobe level (SLL) and a narrower half-power beam width (HPBW). A low SLL is crucial to minimize intervention in the entire side lobe region, whereas long-distance communication requires a low HPBW. The marine predator’s algorithm (MPA) is used here to determine the optimal feeding currents to each array element to reduce the SLL and HPBW values. Two linear antenna array (LAA) design examples and the three elliptical antenna array (EAA) design examples are discussed in this article which are achieved using the optimal current excitations to each array element. Two well-established evolutionary optimization techniques, namely the genetic algorithm (GA) and the differential evolution (DE) technique, are also employed for comparison to demonstrate the superiority of the MPA optimization-based technique. The results achieved utilizing the MPA show the improvement of SLL contraction compared to the uniform antenna array and the methods affirmed in the recently published article.

LPI radar waveform design based on complementary phase and discrete chaotic frequency joint coding

In order to reduce the probability of radar radiation signals being detected by enemy passive detection systems, this paper proposes a phase and frequency joint coding low intercept Radar waveform design method. Based on the linear frequency modulation signal, this method uses complementary binary code and chaotic sequence to phase encode the intra-pulse modulation. Code and frequency coding. The numerical simulation results show that the designed waveform exhibits pseudo-random characteristics in the time-frequency domain, and the low recognition performance is improved; The signal has an extremely low peak sidelobe level after matched filtering, showing excellent low intercept performance; its three-dimensional ambiguity function diagram presents an ideal “graph”. Fishing type”, with good distance, speed resolution and anti-interference characteristics.

Dual Circularly Polarized Diplexer-Antenna Array With Low-Sidelobe Level Based on Gap Waveguide at Ka-Band

Dual Circularly Polarized Diplexer-Antenna Array With Low-Sidelobe Level Based on Gap Waveguide at Ka-Band

An efficient compact blazed grating antenna for optical phased arrays

Abstract Phased arrays are vital in communication systems and have received significant interest in the field of optoelectronics and photonics, enabling a wide range of applications such as LiDAR, holography, and wireless communication. In this work, we present a blazed grating antenna that is optimized to have upward radiation efficiency as high as 80% with a compact footprint of 3.5 µm × 2 µm at an operational wavelength of 1.55 µm. Our numerical investigations demonstrate that this antenna in a 64 × 64 phased array configuration is capable of producing desired far-field radiation patterns. Additionally, our antenna possesses a low side lobe level of −9.7 dB and a negligible reflection efficiency of under 1%, making it an attractive candidate for integrated optical phased arrays.

A 94-GHz Dual-Polarized 1-D Series-Fed Phased Array Antenna With Low Sidelobe Level Based on Multilayer Coreless ABF Substrates

A 94-GHz Dual-Polarized 1-D Series-Fed Phased Array Antenna With Low Sidelobe Level Based on Multilayer Coreless ABF Substrates

A Deep Learning Application for Dolph-Tschebyscheff Antenna Array Optimisation

This paper proposes a design for a Dolph-Tschebyscheff-weighted microstrip antenna array using a deep learning application. For this purpose, a multilayer perceptron and a deep learning model, both created using the same data set generated by a genetic algorithm, were compared. The antenna array population is initially generated randomly and then optimised with a genetic algorithm. The data produced by this model becomes a data set used for training in the deep learning application. The dimensions and specifications of the antenna array are obtained from this application, ensuring precision and optimisation in the design process. A new microstrip antenna array structure is employed for the proposed method, taking advantage of this design technique. The Dolph-Tschebyscheff weights are applied to achieve better characteristics for the microstrip antenna array, thus obtaining low side lobe levels, which are crucial for enhancing signal clarity and reducing interference. The results demonstrate that the proposed algorithm significantly improves the specifications of the structure. This improvement highlights the potential for integrating deep learning with traditional optimisation algorithms for advanced antenna design.

Sidelobes and sideband minimization in time-modulated array antenna based on chaotic exchange nonlinear dandelion optimization algorithm

Time-modulated array antenna (TMAA) is a new type of array antenna based on time modulation technology. By introducing "time" as the fourth dimensional design freedom into the design of conventional array antennas in three-dimensional space, the array antenna has time modulation characteristics, which better controls the radiation characteristics of the array antenna and achieves the best far-field radiation pattern synthesis. This paper designs a Time-modulated linear array (TMLA) with low sidelobe level (SLL) and low sideband level (SBL) based on the chaotic exchange nonlinear dandelion optimization (CENDO) algorithm. Three optimization methods are studied: firstly, determining the optimal on-time (τnn) for each array element; The second is to determine the optimal on-time (τnn) and optimal uniform array element spacing (d) for each array element; The third is to determine the optimal opening time (ton), closing time (toff), and optimal uniform array element spacing (d) for each array element. To achieve simultaneous reduction of sidelobe level and suppression of harmonic interference. The same array model contains different harmonic frequency radiation. In this article, we only considered two harmonic frequencies, namely the first sideband frequency and the second sideband frequency. Because the harmonic of other sideband frequencies has a very small impact on the radiation of the fundamental wave, it can be ignored. To demonstrate the stronger ability of the CENDO algorithm in optimizing Time-modulated array antennas, and in line with the principle of fairness and impartiality, this paper also simulates different Time-modulated array models and compares the results of the CENDO algorithm with other published literature. It is concluded that this study shows lower SLL and lower SBL in different models. This provides a more scientific and accurate explanation of the superiority of the CENDO algorithm compared to other algorithms in the field of antenna optimization in electromagnetics. At the same time, this also provides great research value and fundamental support for designing high-performance Time-modulated array antennas in subsequent engineering applications.

H-plane gap-RGW horn antenna with very low side lobe level

This paper presents and applies a new concept of gap-RGW to develop a new configuration for RGW H-plane horn antennas. The proposed antenna is fully metallic and can generate a very low side-lobe level along with a flat gain response over a reasonable bandwidth, which is one of the advantages of this antenna. A prototype of the presented structure is designed and fabricated which provides the impedance bandwidth (S11 < − 10 dB) of about 25% with SLL < − 20 dB and 2 dB gain variation over the operating bandwidth.

Low-profile, low sidelobe array antenna with ultrawide beam coverage for UAV communication

This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage, low profile, and low Sidelobe Level (SLL) for the application of Unmanned Aerial Vehicle (UAV) air-to-ground communication. The array consists of ten broadside-radiating, ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL. First, an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented. A low-profile, half-mode Microstrip Patch Antenna (MPA) is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole, constructing the compact, end-fire, grounded Huygens source antenna. Then, two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide, broadside-radiating beam. Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance. Experiment indicates an ultrawide Half-Power Beamwidth (HPBW) of 161° and a low SLL of −25 dB with a high gain of 12 dBi under a single-layer configuration. The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.

Broadband Antenna Operating in Sub 6GHz Frequency for Long Range 5G Communication

Abstract: A novel broadband antenna designed for long-range 5G communication in the sub-6GHz frequency band is presented. Through rigorous optimization and simulation, the antenna achieved high gain, low side-lobe levels, and uniform radiationpatterns. Experimental validation confirms its efficacy, offering a compact and robust solution for advancing global connectivity in next-generation wireless networks

Synthesis of Non-Uniform Spiral Antenna with Low Peak Sidelobe Level Using Enhanced Harris Hawks Optimization Algorithm

Synthesis of Non-Uniform Spiral Antenna with Low Peak Sidelobe Level Using Enhanced Harris Hawks Optimization Algorithm

An algorithm for incoherent reception and processing of a multiplexed TMBOC-signal at a single intermediate frequency

Problem statement. A promising direction for the development of the global navigation satellite system is the creation of new types of signals with code separation. High availability and accuracy of consumer location determination refer to signals having an autocorrelation function with a narrow main peak and a low level of side lobes. One of the types of such signals is promising multiplexed TMBOC signals. But the processing of this signal has not been fully studied, namely, signal processing with TMBOC modulation in an incoherent reception mode. Purpose. Synthesis of an algorithm for incoherent reception and processing of a multiplexed TMBOC signal at a single intermediate frequency. Results. Analytical expressions are obtained for the output voltages of the discriminators of the frequency tracking system and the delay tracking system. The schemes of discriminators of the frequency tracking system and the delay tracking system are obtained. Practical significance. The results can be used by specialists in the field of satellite radio navigation in the modernization of global navigation satellite systems.

Concentric Elliptical Antenna Array Synthesis using Sine Cosine Algorithm for Reducing the Sidelobe level

This paper employs the Sine Cosine Algorithm, a recent meta-heuristic method, to enhance the radiation properties of concentric elliptical antenna arrays in far-field applications, such as smart grid wireless communication and the Internet of Things. It focuses on minimizing the Sidelobe Level, a key parameter in antenna radiation, to mitigate unwanted signals and interference. The proposed method, known for its global optimization effectiveness, tackles the challenge of designing sparse multiple concentric elliptical arrays. By using the Sine Cosine Algorithm, the inter-element spacing and optimal determination of amplitude coefficients are achieved, resulting in a radiation pattern with reduced sidelobe level. To showcase the adaptability and superior performance of our proposed algorithm, we systematically evaluated its effectiveness across four distinct sets of concentric elliptical antenna arrays. These arrays comprise varying numbers of elements: (6, 12, 18 elements, 6, 12, 18, 24 elements, 6, 12, 18, 24, 30 elements and 6, 12, 18, 24, 30, 36 elements) with and without a central element. Using the sine cosine algorithm, we synthesize arrays and compare their sidelobe level and First Null Beam Width values with those from recent methods. Our findings consistently shows that the proposed algorithm consistently outperforms alternatives, yielding significantly lower sidelobe level values in all comparisons.

Slotted meandered waveguide antenna for X-band radar applications

ABSTRACT This work presents a unique one-dimensional (1D) FSA powered by rectangular meander waveguide which finds usage in bird monitoring and detection in wind farms. Large scan volume, high frequency sensitivity, lower side lobe level and excellent directivity are few of the varied advantages of the suggested approach. The suggested travelling-wave FSA operates in the X-band uses a periodically loaded standard WR90 waveguide and is vertically polarised. The propagation properties and fundamental ideas of the meander-line unit are thoroughly studied for frequency-scanning based applications. The scanning performance over frequency range is enhanced by using the proposed meandering feeding mechanism. Dumbbell-shaped radiating slots are utilised in the waveguide. The beam width in the elevation plane is narrowed by embedding an E-plane horn antenna over it. Using CST microwave studio, the proposed FSA with 10 radiating elements is simulated in order to predict the scanning performance over the frequency range of 9.425 to 10.025 GHz. The results demonstrate a gain above 21 dBi and a high 55-degree scanning coverage performance. The lower SLL is observed around 13 dB. Aluminium is used in the fabrication of the suggested approach. When the FSA is evaluated after manufacture, measurements and simulations accord quite well.

Low sidelobe cosecant-squared pattern time-modulated antenna array with harmonic suppression

In this paper, a pulse shifting approach with phase-only weighting is proposed for a cosecant-squared radiation pattern time-modulated linear array (TMLA) synthesis. The sidelobe level (SLL) of fundamental signal and maximum sideband levels (SBLs) of harmonic signals is simultaneously reduced. This is achieved by controlling both the phase and the periodic switching time sequence of each element of the TMLA. In pulse shifting, the on–off switching sequence of each radiating element is characterized by a switch-on instant and interval within the modulation period which increases the degrees of freedom. A genetic algorithm (GA) is employed to optimize the switch-on and switch-off instants of each time pulse along with the phase weight for each element in the antenna array. The simulation results reveal that the proposed method can achieve the required patterns with very low SLL and SBLs.

Fast Low-Sidelobe Pattern Synthesis Using the Symmetry of Array Geometry.

Array pattern synthesis with low sidelobe levels is widely used in practice. An effective way to incorporate sensor patterns in the design procedure is to use numerical optimization methods. However, the dimension of the optimization variables is very high for large-scale arrays, leading to high computational complexity. Fortunately, sensor arrays used in practice usually have symmetric structures that can be utilized to accelerate the optimization algorithms. This paper studies a fast pattern synthesis method by using the symmetry of array geometry. In this method, the problem of amplitude weighting is formulated as a second-order cone programming (SOCP) problem, in which the dynamic range of the weighting coefficients can also be taken into account. Then, by utilizing the symmetric property of array geometry, the dimension of the optimization problem as well as the number of constraints can be reduced significantly. As a consequence, the computational efficiency is greatly improved. Numerical experiments show that, for a uniform rectangular array (URA) with 1024 sensors, the computational efficiency is improved by a factor of 158, while for a uniform hexagonal array (UHA) with 1261 sensors, the improvement factor is 284.

High‐gain dual‐wideband ±45° dual polarization (DWDP) antenna for indoor distributed antenna system (IDAS) applications

SummaryThis paper presents two different configurations of ±45° dual‐wideband dual‐polarized (DWDP) antennas. The antenna comprises eight end‐loaded broadband dipoles grouped into two sets based on the bands of operation. The high‐frequency dipoles are strategically placed within the low‐frequency ones to form the elementary unit. Further optimization has been performed on the elementary unit in terms of the radiator placement to suppress sidelobe levels for array formation. Both configurations are meticulously fabricated using an all‐metal structure, demonstrating durability and the simplicity of fabrication. The antenna designs achieve ±45° polarization, high gain, satisfactory cross‐polarization discrimination (XPD), and wide impedance bandwidth covering 0.67–1.04 GHz and 1.54–3 GHz bands. Despite the nested configuration, mutual coupling is well within acceptable limits. Formation of the array based on the optimum elementary unit has been investigated by simulation, revealing reasonable gain enhancement and low sidelobe levels across all bands. This comprehensive approach yields a robust, high‐performing antenna configuration suitable for indoor distributed antenna system (IDAS) applications.

Effect of Panel Misalignment Error Distribution on the Radiation Pattern of Leighton Chajnantor Telescope’s Antenna

The Leighton dish formerly at the Caltech Submillimeter Observatory will be reassembled to become the Leighton Chajnantor Telescope (LCT). It will be required to demonstrate high surface accuracy and controlled radiation patterns at high frequency, which are largely limited by surface error due to panel misalignment on the primary reflector. Not only the surface rms error but also the error distribution has effect on the radiation pattern of the antenna. Therefore, analyzing the effect of error distributions resulting from various panel misalignments on the radiation pattern of the antenna will facilitate better compensation of surface errors during the reassembly process. To acquire the radiation pattern of LCT’s antenna with panel misalignments, we first propose a simulation method based on physical optics and the physical theory of diffraction, which offers precise results but is time-consuming, especially at high frequencies. Then, we propose a rapid computation method that combines the method of calculating the optical path difference (OPD), the OPD fitting method, and the aperture integration method for segmented reflectors. Experimental results demonstrate that the rapid computation method is highly efficient and accurate compared to the simulation method. In order to show the effect of error distributions due to two typical panel misalignments (i.e., piston and tip-tilt) on radiation patterns, experiments are conducted using the two proposed methods for various error distributions. These experiments indicate that for the same surface rms error, smaller panel errors at smaller normalized aperture radii are more conducive to achieving improved characteristics of the radiation patterns, such as reduced peak gain losses and lower sidelobe levels. Additionally, comparison experiments also reveal that variations in piston error have a greater impact on the radiation patterns than variations in tip-tilt error under the same surface rms error.