Search Results (37)

In this paper, we propose a signal intelligence (SIGINT) drone swarm system with a three-dimensional (3-D) volumetric self-complementary array configuration. In the proposed system, multiple drones form two array layers separated along the boresight direction of the system, providing sufficient spacing between drones mounting an antenna element. The antenna elements in one array layer are arranged in a complementary manner to fill empty spaces in the other layer, allowing the system to maximize the number of drones deployed within the aperture area. As a result, the effective electrical spacing at 300 MHz is reduced from 1.7λ and 0.9λ to 0.85λ and 0.45λ along the x- and y-axes, respectively. The array gains of the proposed system are 3.96 dBi, 6.40 dBi, and 15.3 dBi at 100 MHz, 200 MHz, and 300 MHz, and the side-lobe levels (SLLs) are −13.0 dB, −12.7 dB, and −13.0 dB. In addition, the proposed drone swarm SIGINT system is evaluated in a practical SIGINT environment that considers terrain features, and then the detection performance is compared with those of conventional ground-based and airborne SIGINT systems. In this SIGINT scenario, the proposed system can detect signals over an extended detection range of 150 km than those of ground-based and airborne systems. Full article

This paper presents a novel design technique using beam-forming networks based on CORPS (coherently radiating periodic structures) technology to achieve the simplification of the feed network of Fermat spiral antenna arrays. The use of one-layer CORPS structures generates the values of co-phasal excitation required for the feeding network system based on subarrays. The setting of subarrays has been achieved through the study of the behavior of phases of each antenna element in scanning. In this way, elements that exhibit linear behavior in scanning can be grouped. Furthermore, the geometry of the antenna array system using a Fermat spiral configuration applies methods for side lobe level (SLL) reduction such as: a raised cosine amplitude excitation and optimization of the amplitude excitations through the method of genetic algorithms (GA), CORPS amplitude distribution and uniform distribution. The contribution of this paper is to provide a design of a phased antenna system for a Fermat spiral array geometry considering the analysis and study in the performance of SLL, scanning range, and the phase shifters reduction. Full-wave electromagnetic results are provided for the full phased antenna system by using circular patch antenna elements at a frequency of 6 GHz. If our system using CORPS is compared with the use of a conventional feeding network where every antenna in the spiral array is fed with a phase shifter, the benefits of using this phased spiral array system are: a phase shifters reduction capability of 33%, steering ranges of ±22° in the elevation plane, low SLL using the proposed distribution techniques. Furthermore, the choice of CORPS 2×3 networks would allow the integration of the antenna system where one layer is proposed for the feeding network and another layer for the antenna array with the aim of avoiding crossings and unwanted radiation. Full article

This work presents the design and experimental validation of a high-performance 6-port MIMO antenna array designed for radar applications in the 24 GHz Industrial, Scientific, and Medical (ISM) band. The proposed design, configured as a 1 × 10 series-fed microstrip patch array on an RT/Duroid 5880 substrate, is engineered to meet the demanding requirements of automotive and industrial radar systems, where high resolution and target discrimination are critical. A key challenge in such dense MIMO arrays is mutual coupling, which was addressed by integrating novel metamaterial structures between the radiating elements. These structures effectively suppress surface waves, resulting in exceptional inter-port isolation exceeding 46 dB at 24.3 GHz. The antenna achieves a peak gain of 17.4 dBi, ensuring sufficient range for sensing applications. Furthermore, the radiation pattern exhibits a simulated low side lobe level (SLL) of −24.6 dB in the E-plane, and −15.8 dB in the H-plane, a critical parameter for minimizing false detections and enhancing accuracy in cluttered environments. With an operational bandwidth of 0.71 GHz, the proposed design demonstrates comprehensive performance metrics—high gain, outstanding isolation, and low SLL—that surpass many existing MIMO solutions. The results confirm the antenna’s strong potential for advanced MIMO radar systems operating in the 24 GHz-ISM band, paving the way for reliable high-resolution sensing. Full article

This article presents a novel strategy for the design of planar phased arrays using Fibonacci-based partitioning combined with a random multi-objective search. This approach intends to minimize the number of phase shifters used by the system while maintaining the radiation characteristics required for Ku-band user terminals in Low Earth Orbit (LEO) satellite communications. This methodology efficiently tessellates a $16\times 16$ antenna array, reducing the solution search space size and improving algorithmic computational time. From a total of 409,600 possible configurations, an optimal candidate solution was obtained in 2 h. This configuration achieves a balanced trade-off between radiation performance metrics, including side lobe level (SLL), first null beamwidth (FNBW), and the number of phase shifters. This optimal design maintains a value of SLL below $-15$ dB across all the azimuth scanning angles, with a beam steering capability of $\theta =-{40}^{\circ }$ and $0^{\circ }\le \varphi \le {360}^{\circ }$. These results demonstrate the suitability of this novel approach regarding Ku-band satellite communications, providing efficient and practical solutions for high-demand internet services via LEO satellite systems. Full article

This study presents a transmitarray antenna design operating at a center frequency of 9 GHz, addressing the need for high-gain and broad bandwidth antennas in modern data communication. The proposed design is structured as a quad-layer configuration using FR-4 dielectric substrates. The transmitarray’s phase profile is tailored to deliver a wideband flat response with low Side Lobe Level (SLL) and stable aperture efficiency across the operating band. It achieves a 1-dB gain bandwidth of 12.12% (from 8.56 GHz to 9.67 GHz) and a 3-dB gain bandwidth of 49.43% (from 8.45 GHz to 13.46 GHz) with an aperture efficiency of 21.3%. A prototype of the proposed design with 11 × 11 elements was fabricated and measured, and its measurement results closely aligned with simulation results, validating its performance. The proposed simple design realizes reduced complexity and fabrication costs while expanding operational gain bandwidth, thereby demonstrating substantial promise for next-generation X-band communication systems. Full article

This paper presents the design, simulation, and experimental validation of a dual-Circularly Polarized (CP) array antenna to be used as single element for a bistatic radar system, aimed at detecting and tracking objects in Low Earth Orbit (LEO). The antenna operates at 412 MHz in reception mode and consists of an array of 19 slotted-patch radiating elements with a cavity-based metallic superstrate, designed to support dual circular polarization. These elements are arranged in a hexagonal configuration, enabling the array structure to achieve a maximum realized gain of 17 dBi and a Side Lobe Level (SLL) below −17 dB while maintaining high polarization purity. Two identical analog feeding networks enable the precise control of phase and amplitude, allowing the independent reception of Right-Hand and Left-Hand Circularly Polarized (RHCP and LHCP) signals. Full-wave simulations and experimental measurements confirm the high performance and robustness of the system, demonstrating its suitability for integration into large-scale Space Situational Awareness (SSA) sensor networks. Full article

This paper presents the modified arithmetic optimization algorithm (MAOA), a swift and effective optimization algorithm specifically designed for electromagnetic applications. Its primary advantage is its ability to avoid local minima by striking a balance between global exploration and local exploitation searches. This equilibrium is maintained through three key improvements: an enhanced initialization process, a distinctive guidance mechanism for steering searches, and an additional learning phase to refine newly found solutions. This process innovation significantly boosts MAOA’s performance in addressing both constrained and unconstrained optimization challenges. In this study, MAOA is applied to optimize the spacing and current amplitude of linear antenna array (LAA) elements, with the goal of minimizing peak side lobe level (PSLL), close-in side lobe level (CSLL), and overall side lobe level (SLL), both with and without constraints on first null beamwidth (FNBW), as well as null positioning with SLL minimization. Ten designs, comprising 10 and 20 antenna elements of LAA and one 14-element circular antenna array (CAA), showcase MAOA’s proficiency in antenna array pattern synthesis. Optimizing element positions results in a PSLL of −21.28 dB, a CSLL of −34.50 dB, and a null depth of −89.00 dB, while optimizing current amplitude achieves a PSLL of −24.32 dB, a CSLL of −29.73 dB, and a null depth of −77.60 dB across various antenna designs. Simulation results reveal that MAOA significantly surpasses traditional uniform linear arrays (ULA) and established optimization techniques. Its superiority is further confirmed through a Wilcoxon rank-sum and Friedman test. Full article

This paper introduces a novel framework for designing wideband antenna arrays using self-similar Eisenstein fractal geometries combined with multi-objective evolutionary optimization techniques. The approach employs multi-objective binary differential evolution (MO-BDE) for array thinning and multi-objective particle swarm optimization (MO-PSO) for optimizing amplitude excitations. This integrated methodology reduces the number of active elements while enhancing overall array performance. The optimization process targets minimizing peak side lobe levels and maximizing directivity over a broad frequency range. Two designs are explored: one optimized at a primary frequency, and another providing consistent wideband behavior. The proposed method achieves a 37.5% reduction in active elements. Design A shows an SLL reduction of −12 dB at the target frequency, while Design B maintains up to −3 dB SLL improvement across the bandwidth. The results confirm the efficacy of the proposed synthesis method for developing scalable, energy-efficient antenna arrays for next-generation systems. Full article

A low profile dual polarized transmitarray antenna, made of three identical layers, is proposed in this paper for Ku-band applications. The transmitarray comprises 22 × 22 symmetrical unit cells. A 3-bit phase compensation layer with less than α_T = 1.3 dB transmission loss and 2π transmission phase coverage for both linear polarized components at the central frequency f₀ = 12 GHz is designed. Moreover, for an incidence angle θ = 30°, the unit cell transmission loss is less than 2 dB; the transmission phase is close to the transmission phase at zero incidence angle θ = 0°. The fabricated transmitarray exhibits a measured peak gain of Gm₀ = 21 dB at the frequency f₀ = 12 GHz. The corresponding measured 1 dB gain bandwidth is BWg = 10.8% (11.1–12.4 GHz). The measured peak side lobe levels are SLL₀ = −20.8 dB at f₀ = 12 GHz. The transmitarray antenna can be used for beam steering up to an angle of γ_max = ±30° with a measured scan loss △G_MSL1 = 2.73 dB at f₁ = 12.4 GHz. Full article

A mechanical beam-scanning reflectarray (RA) antenna is presented for Ka band. The 1D steering of the beam is achieved through linear in-plane panel translations, which can be implemented at low cost using a rail-mounted moving RA panel. Compared to related works, a highly uniform beam level is achieved with a remarkably compact antenna profile. A new technique is also proposed to mitigate the high side lobes caused by the compact antenna optics, achieving an estimated 2.3 dB reduction in maximum SLL. The manufactured prototype has a panel size of 256.4 by 187.2 mm with 2898 elements, and an $F/D$ of only 0.47. A measured scan loss of 1.1 dB is achieved over a 45-degree scanning range. The measured gain is 31.6 dBi and the aperture efficiency is 24.7% at the design frequency of 29.5 GHz, with SLL between −9.4 and −17.5 dB. In-band measurements show a 1 dB bandwidth from 28 to over 32 GHz (11.9%). Full article

A method for the synthesis of equally spaced antenna arrays based on the extension of the Orchard–Elliott–Stern technique to radiation patterns with three roots on the negative real axis of the Shelkunoff unit circle is presented. One of these roots is placed on the unit circle and the other two are off the unit circle with coordinates r and $1/r$. For a desired side lobe level (SLL), the synthesis of patterns with these roots allows for a multiplicity of solutions with different amplitude ratios, obtained by varying the value of r, each of which presents radiation patterns with different beamwidths and directivity, but with two fewer side lobes than the patterns obtained without these restrictions in the roots. The technique has been thoroughly applied to Dolph–Chebyshev patterns of 10, 18 and 40 elements, with a $\lambda /2$ spacing and an SLL that guarantees maximum directivity in both cases. This approach ensures the study of examples of all sizes, from small to large. The findings derived from this technique would be applicable in the domain of wireless communications, where the necessity arises for radiation patterns that exhibit low SLL and adaptive beamwidth. Full article

A frequency-reconfigurable MIMO antenna with high gain, low mutual coupling and highly suppressed side lobe level (SLL) for applications in 24 GHz ISM band sensing and automotive radar systems was designed, modeled, and simulated. The reconfigurability feature was modeled with the implementation of a varactor diode in the model to alter the frequency in a wide band around 24 GHz. The design features 2- and 4-port MIMO antenna each comprising a 1 × 8 microstrip patch array. At the core of achieving both a high gain of 16 dBi and high isolation of 38.4 dB at a resonance frequency of 24.120 GHz lies the integration of a metamaterial absorber, comprising an optimized split-ring unit cell to effectively mitigate interference among the MIMO elements. Noteworthy impedance bandwidths of the sensor antenna span from 23.8 to 24.3 GHz, catering to diverse frequency requirements. The proposed sensor antenna feature a half-power beamwidth of 74° in the E-plane and 11° in the H-plane and an SLL of −24 dB at 24.120 GHz showing its robust performance characteristics across multiple operational dimensions. Full article

We numerically investigate the relationship between the main parameters of thinned antenna arrays using a specifically designed evolutionary algorithm, the Multi-Objective Pareto Evolution for Thinning (MOPET). We provide some useful results that allow for the assessment of the achievable performance of antenna arrays and help researchers and practitioners design radar, 5G, and 6G systems. In particular, our approach allows us to quantify the advantage of thinned arrays with respect to traditional equispaced arrays (EA); as an example, using the same number of radiators, we can obtain the same directivity of an EA with a reduction in the side-lobe level (SLL) of more than 10dB, or increase the directivity of a couple of dB maintaining the same SLL of the EA, or get a combination of the two improvements. Moreover, the advantage of thinned architectures with respect to standard EA seems to improve with the increase in the dimension of the array. Full article

In this paper, a hybrid optimization method utilizing a pseudo-random algorithm and convex optimization is proposed to avoid grating lobe and achieve lower side lobe level (SLL) of a planar sparse array when the minimum inter-element distance is one wavelength. The pseudo-random algorithm is utilized to distribute the positions of elements. The convex algorithm is utilized to optimize the excitations of elements. The results show that a planar sparse array with no grating lobe and peak side lobe level (PSLL) of $-17$ dB can be obtained with a minimum inter-element distance of one wavelength, which indicates the effectiveness of the hybrid optimization method. In addition, beam steering can be achieved within an ${80}^{\circ }$ field of view range. Full article

Circular antenna arrays (CAAs) find extensive utility in a range of cutting-edge communication applications such as 5G networks, the Internet of Things (IoT), and advanced beamforming technologies. In the realm of antenna design, the side lobes levels (SLL) in the radiation pattern hold significant importance within communication systems. This is primarily due to its role in mitigating signal interference across the entire radiation pattern’s side lobes. In order to suppress the subsidiary lobe, achieve the required primary lobe orientation, and improve directivity, an optimization problem is used in this work. This paper introduces a method aimed at enhancing the radiation pattern of CAA by minimizing its SLL using a Hybrid Sooty Tern Naked Mole-Rat Algorithm (STNMRA). The simulation results show that the hybrid optimization method significantly reduces side lobes while maintaining reasonable directivity compared to the uniform array and other competitive metaheuristics. Full article