Array Radiator Research Articles

Design and investigation of UWB antenna with triple notched band for 5G wireless communication

ABSTRACT Two novel antennas are presented in this article. UWB and UWB antenna with triple notched band are designed using an elliptical array structure. To improve the gain and the impedance bandwidth, a new methodology for optimization of an elliptical array UWB antenna with an uncentered feedline model is presented. Based on the Response Surface Modelling, two parameters (Wopt1 and Wopt2) control the return loss of UWB antenna. The mathematical models of S11 is developed using non-regression analysis, and this antenna can be used for various applications such as Wi-Fi, 5 G, 4 G LTE, X-Band application, C-Band application. The band rejection technique is implemented to designed triple notched UWB antenna to reduce the cost of the UWB channel. The first band (2–3 GHz) is rejected by embedding a rectangular stub on the modified partial ground plane on UWB antenna. By etching a three rectangular slot on the elliptical array radiator, two notched bands 2–3 GHz and 5–6 GHz bands are rejected. By embedding two arcs on the elliptical array radiator, triple interfacing bands 2–3 GHz, 5–6 GHz, and 7.8–8.4 GHz are rejected. Two proposed antennas are designed using FR4 substrate and fabricated and verified experimentally. This antenna offers excellent performance and is well-suited for 5 G wireless communications.

Ridged Apertures for LEO Direct Radiating Arrays in Ka-Band

This paper presents an extensive performance analysis of open-ended waveguide elements for direct radiating arrays with a high scan angle (±50° /60°). The evaluated designs are based on square and hexagonal apertures loaded with ridges. Both square and triangular lattices are considered in the framework of Ka-band downlink design requirements for future LEO mega-constellations. The parameter space defined by the monomodal condition has been explored to find an optimum value for each structure. The analyses carried out with both infinite and finite full-wave models in terms of active reflection coefficient, scan loss and cross-polar discrimination are in good agreement.

Si/InAs/Ag metamaterial for strong nonreciprocal thermal emitter with dual polarization under a 0.9 T magnetic field

The current nonreciprocal thermal emitter has been proven to completely violate the previous Kirchhoff's law. And the majority of related nonreciprocal devices operate under single polarization with few dual-polarization nonreciprocal designs. Therefore, dual-polarization nonreciprocal thermal radiation has great research prospects. In addition, many previous designs of nonreciprocal devices required external magnetic field energy of 3 T even higher, which is difficult to meet in practical applications. Therefore, this article investigates the strong nonreciprocal dual-polarization thermal radiation of cuboid arrays under lower external magnetic field. It is constructed by silicon, silver layer, InAs layer, and cuboid arrays. Finally, dual-polarization nonreciprocal radiation was achieved in a magnetic field of only 0.9 T, and the nonreciprocal efficiency has been significantly improved. The physical phenomenon of dual-polarization strong nonreciprocal radiation exhibited by the proposed device was explained by utilizing the electromagnetic field distribution at the resonant wavelength. It can also maintain good nonreciprocal properties under different structural parameters. Therefore, our proposed solution provides new opportunities for energy harvesting and thermal radiation control.

High-efficiency thermo-optic control of a longitudinal radiation angle in a silicon-based optical phased array by leveraging the backside air trench structure.

We proposed a 2D 1 × 64 silicon optical phased array with a backside silicon-etched structure to achieve high tuning efficiency and a wide longitudinal steering range. At the radiator array, the n-i-n heater was implemented to steer the light in a longitudinal direction through the thermo-optic effect. The deep reactive ion etching process was utilized to generate the 600 µm depth air trench with a 1.8 cm2 area from the backside of the radiator array. We achieved almost 100% increment in terms of tuning efficiency, which is 1.56°/W for the proposed structure and 0.78°/W for the conventional structure.

A dual-band dual-circularly polarized structure reused shared-aperture antenna with high aperture efficiency for satellite communications

A novel S/Ka dual-band dual-circularly polarized (CP) shared-aperture antenna is proposed in this paper. In the Ka-band, the reflectarray adopts two distinct CP elements, both of which achieve 360° phase shift and linear phase response in the wideband. In the S-band, the radiation array adopts a 4 × 4 units cut-corner square patch to achieve CP performance. Additionally, a steerable beam is achieved through a phase shift feeding network. To effectively improve the antenna aperture utilization and efficiency, the S-band radiator is reused as a part of the Ka-band reflecting ground to realize the aperture-sharing. Experimental results demonstrate that the S-band operating bandwidth covers 2.35–2.7 GHz, achieving a peak gain of 18.6 dBic and an aperture efficiency of 89.2 %. Furthermore, the S-band enables ± 30° beam steering. In the Ka-band, the operating bandwidth covers 28–32 GHz, with a measured 2-dB axial ratio bandwidth is 10.3 %, a peak gain of 37.5 dBic, and an aperture efficiency of 48.1 %. Therefore, a dual-band dual-CP shared-aperture antenna with high aperture efficiency is realized. The antenna offers beam steering in the S-band and wideband capabilities in the Ka-band, making it a valuable candidate for satellite communication systems.

A Compact Linear Microstrip Patch Beamformer Antenna Array for Millimeter-Wave Future Communication.

5/6G is anticipated to address challenges such as low data speed and high latency in current cellular networks, particularly as the number of users overwhelms 4G and LTE capabilities. This paper proposes a microstrip patch antenna array comprising six radiating patches and utilizing a microstrip line feeding technique to facilitate the compact design crucial for 5G implementation. ROGER 3003, chosen for its advanced and environmentally friendly features, serves as the dielectric material, ensuring suitability for 5G and B5G applications. The designed antenna, evaluated at a resonating frequency of 28.8 GHz with a -10 dB impedance bandwidth of 1 GHz, offers a high gain of 9.19 dBi. Its compact array, cost-effectiveness, and broad impedance and radiation coverage position it as a viable candidate for 5G and future communication applications.

Two port high gain and low mutual coupling dielectric resonator based array antenna for 5G mm-wave applications

In this communication, a two-port ceramic based array radiator at mm-wave frequency range is structured and analysed. 3-dB power divider based microstrip feed line is utilised to excite the rectangular aperture. The same aperture is used to feed the ceramic, which creates fundamental hybrid mode (HEM11δ ) inside the dielectric resonator. Feeding structure is designed on RT Duroid substrate having thickness 0.254 mm and permittivity 2.2. The length and width of the substrate is 60.0 mm and 30.0 mm respectively. Alumina material is used to design the ceramic having permittivity 9.8. The exclusive feature of the proposed antenna design is to get highly directional pattern along with high gain (more than 13.5 dBi) in mm-wave frequency range with the assistance of 1*4 array structure. Orthogonal orientation of antenna ports adds the polarization diversity concept, which in turns improve the isolation level more than 50 dB. Measured results confirm that the designed antenna works effectively in between 31.5–32.8 GHz. Broadside radiation pattern and good value of Envelop correlation coefficient (less than 0.1)/Diversity gain (10.0 dB) make the designed antenna employable for n257 frequency band of 5G mm-wave applications.

Mutual coupling suppression of MIMO array with non-uniform curved-strip EBG structure via shape and layout co-optimization

In this paper, a shape and layout co-optimization method for mutual coupling suppression of MIMO array with non-uniform curved-strip electromagnetic bandgap (EBG) structure is proposed. The curved shape of the EBG structure between the microstrip patches is described to achieve the mutual coupling suppression by the spline curve and moving it the same displacement along the y-axis in both directions, where the spline curve is formed by the coordinates of the control points corresponding to the Bessel function. Moreover, the non-uniform layout design of the EBG structure is introduced to further adjust the radiation field and the surface current distribution of the coupled array. Through simultaneously optimizing the curved shape and layout parameters of the strip EBG structure, the expected array radiation and decoupling performances are obtained. The effectiveness of the proposed method is validated by a MIMO array with edge-to-edge distance of only 0.1λ0 in the 5G WLAN frequency band. The simulation and experiment results indicate that, compared with non-EBG and the initial uniform strip EBG, the proposed EBG structure can provide the advantage of significantly reducing the mutual coupling to −35.20 dB and effectively improving the isolation between the elements, meanwhile ensuring the MIMO array performances.

Far-field mapping and efficient beaming of second harmonic by a plasmonic metagrating

Abstract We study numerically and experimentally the second-harmonic generation (SHG) from rectangular metagratings of V-shaped gold nanoantennas. We show that by carefully engineering the array pitch to steer the diffraction orders toward the single antenna emission, the extracted signal is maximized. This enhancement is attributed to the angular overlap between the radiation pattern and array factor and is comparable to the improvement yielded by the coupling of surface lattice resonances (SLRs) with local modes. Moreover, we demonstrate a simple technique to experimentally reconstruct the emission diagram of an antenna from measurements of the collective grating response as a function of the excitation angle. Excellent agreement is obtained with simulations when the sample is immersed either in air or in water, which is crucial in view of future sensing application. Thanks to the high signal-to-noise ratio and low dependence on the statistical particle dispersity, this method constitutes an effective alternative to back-focal plane imaging when very weak signals such as SHG are involved.

High Elevation Radiation Array (HERA) detectors for airborne thunderstorm investigations

A high-energy atmospheric physics phenomenon, referred to as a terrestrial gamma ray flash (TGF), is associated with lightning and produces large bursts of energetic photon radiation. TGFs will be investigated using a suite of gamma-ray instruments designed and constructed to fly on ten United States Air Force (USAF) WC-130J Hurricane Hunter aircraft as part of an aircrew ionization study led by the Air Force Institute of Technology (AFIT) and the United States Air Force School of Aerospace Medicine (USAFSAM), in cooperation with the 53rd Weather Reconnaissance Squadron (WRS). Each instrument consists of one NaI and one plastic detector, a GPS timing device, and an instrument computer that performs data acquisition. High Elevation Radiation Array (HERA) detectors will be employed to maximize the chances of observing TGFs near their source and to gain a better understanding of their origin, mechanism, ubiquity, and to assess potential hazards posed to military and commercial aircrew and passengers. The HERA program, deployed on 10 separate Air Force aircraft over a multi-year campaign, will result in thousands of observational flight hours and be the largest concerted effort to date to observe TGFs in situ through aircraft observations. In this paper, we give an overview of the scientific goals of this campaign and how the HERA instruments have been designed to meet those goals. We include a detailed description of the HERA instrument, along with mass model and signal processing simulations.

An Efficient MLFMA for Accurately Analyzing Electromagnetic Radiation and Coupling Characteristics of Large-scale Antenna Arrays Mounted on Platform

A multilevel fast multipole algorithm (MLFMA) for analyzing electromagnetic radiation and coupling characteristics of large-scale antenna arrays mounted on the platforms is presented in this paper. Compared with the method of moments (MoM), the MLFMA can be used to calculate larger scale problems with limited resources. First, waveport model of the MLFMA based on the equivalence principle and mode matching theory is established to efficiently and accurately simulate the antenna array. Then, a preconditioning approach for solving the radiation problems with the waveports is designed to improve convergence of the MLFMA. An initial guess construction method is proposed to accelerate the MLFMA computation for the multi-excitation problems, which can reduce the iteration time by at least 50%. Numerical results demonstrate accuracy and efficiency of the proposed method.

Design and Simulation of a High Performance 5G mm-Wave MIMO Antenna Array for Mobile Applications

This paper presents the design and simulation of an efficient multiple input multiple output (MIMO) antenna array for 5G millimeter-wave (mm-wave) mobile applications. With a dielectric constant of 2.2 and a loss tangent of 0.0009, the substrate employed is a Rogers RT5880 that is 0.254 mm thick. The 37 GHz frequency spectrum, reserved for millimeter-wave mobile applications for 5G, is covered by the proposed MIMO antenna arrays. The single antenna element has a gain of 6.44 dBi, which is increased to 7.89 dBi with a two-element array configuration and 10.88 dBi with a four-element array configuration. The proposed MIMO antenna array performance metrics—including reflection coefficient, VSWR, radiation efficiency, and gain—are seen and discovered to be below the accepted threshold. In the desired operating frequency band, it is noticed that more than 85% of the proposed MIMO antenna array's radiation efficiency is achieved. According to simulation findings, the proposed design may be potentially feasible for mobile applications using millimeter waves in the 5G network.

Characterization of human extreme heat exposure using an outdoor thermal manikin

Extreme heat is a current and growing global health concern. Current heat exposure models include meteorological and human factors that dictate heat stress, comfort, and risk of illness. However, radiation models simplify the human body to a cylinder, while convection ones provide conflicting predictions. To address these issues, we introduce a new method to characterize human exposure to extreme heat with unprecedented detail. We measure heat loads on 35 body surface zones using an outdoor thermal manikin (“ANDI”) alongside an ultrasonic anemometer array and integral radiation measurements (IRM). We show that regardless of body orientation, IRM and ANDI agree even under high solar conditions. Further, body parts can be treated as cylinders, even in highly turbulent flow. This geometry-rooted insight yields a whole-body convection correlation that resolves prior conflicts and is valid for diverse indoor and outdoor wind flows. Results will inform decision-making around heat protection, adaptation, and mitigation.

A 299–315-GHz Dual-Band Radiator Array With Cascaded Transmission Line-Based Feedback Network for Phase Noise Improvement

A 299–315-GHz Dual-Band Radiator Array With Cascaded Transmission Line-Based Feedback Network for Phase Noise Improvement

Synthesis of Antenna Array Radiation Pattern at Large Scanning Angles Using Genetic Algorithm

At present, in most modern communication systems, for example, in modern satellite terminals, the use of scanning beam antennas, i. e. antenna arrays is assumed. At the same time, at large scanning angles, the side lobe level (SLL) increases strongly and decrease in the gain is observed. In this regard, the problem of finding a procedure for synthesizing an amplitude-phase distribution (APD) with low SLL and high gain (G) at large scanning angles comes up. One of the ways to reduce SLL and compensate for the decrease in G is to synthesize the optimal APD (in terms of the maximum G and minimum SLL) using optimization algorithms. At the same time, taking into account the characteristics of the radiation pattern of the array emitters requires numerical electrodynamic calculation. The goal of this paper is to develop a procedure for the synthesis of APD with low SLL for linear and rectangular antenna arrays at various, including large, scanning angles and compensation for G reduction using a genetic algorithm and numerical electrodynamic calculation. The methods for studying the characteristics of antenna radiators are numerical electrodynamic modeling by the finite element method (FEM) in Ansys HFSS computer-aided design system and optimization of the APD for a given radiation pattern(RP) by a random search method using partial diagrams of antenna elements. The novelty is the combination of accurate numerical electrodynamic calculation of the RP of antenna elements and optimization search for APD for the synthesis of the required RP using partial diagrams. As a result, a procedure for APD synthesis of linear and uniform rectangular equidistant (for example, 8- and 64-element) antenna arrays has been developed, taking into account the exact electrodynamic characteristics of antenna elements and their mutual resistance. Radiation patterns were obtained taking into account the effect of neighboring elements, with the help of which, using a genetic algorithm, APDs on emitters were found at different scanning angles. The change in SLL and G of the antenna array is analyzed at different scanning angles using different APDs. The proposed algorithm allows to synthesize APD for a RP with low SLL and high G at scanning angles up to 40° for linear antenna array and up to 80° in the case of a uniform rectangular antenna array. The results of this work are relevant in the problems of radiation pattern synthesis, since the proposed solution provides a significant gain in the radiation pattern synthesis rate of APD of linear and rectangular antenna arrays, especially for systems with a large number of antenna elements. At the same time, it is possible to maintain a high G at large scanning angles, and achieve a significant reduction of SLL.

Generation of a super-oscillation magnetization hotspot by reversing the electric dipole array radiation

We propose an all-optical approach to realize a super-oscillatory longitudinal magnetization hotspot with about 0.1λ in a 4π focusing system using time-reversed dipole radiation and vector diffraction theory calculations. Such a magnetization behavior is induced by focal fields of opposite polarities in the central and peripheral regions based on the inverse Faraday effect. By regulating the destructive interference in the central and peripheral regions of the focal field, a super-oscillating magnetization field is generated. Moreover, two important parameters affect the size of the magnetization field are also explored. Superoscillating magnetization hotspots in the focal region can be achieved by either increasing δ (the intensity of electric field) or reducing dn (the distance of electric field). The achieved ultrasmall magnetization spot shows great prospects in high-density magnetic recording, magnetic resonance imaging, and magnetic sensors.

Live-cell imaging Unveils stimulus-specific dynamics of Nrf2 activation in UV-exposed melanoma cells: Implications for antioxidant compound screening

The transcription factor Nuclear factor e2-related factor 2 (Nrf2) is pivotal in orchestrating cellular antioxidant defense mechanisms, particularly in skin cells exposed to ultraviolet (UV) radiation and electrophilic phytochemicals. To comprehensively investigate Nrf2's role in maintaining cellular redox equilibrium following UV-induced stress, we engineered a novel Nrf2 fusion-based reporter system for real-time, live-cell quantification of Nrf2 activity in human melanoma cells. Utilizing live quantitative imaging, we dissected the kinetic profiles of Nrf2 activation in response to an array of stimuli, including UVA and UVB radiation, as well as a broad spectrum of phytochemicals including ferulic acid, gallic acid, hispidulin, p-coumaric acid, quercetin, resveratrol, tannic acid, and vanillic acid as well as well-known Nrf2 inducers, tert-butylhydroquinone (tBHQ) and sulforaphane (SFN). Intriguingly, we observed distinct dynamical patterns of Nrf2 activity contingent on the specific stimuli applied. Sustained activation of Nrf2 was empirically correlated with the increased antioxidant response element (ARE) activity. Our findings demonstrate the nuanced impact of different phenolic compounds on Nrf2 activity and the utility of our Nrf2-CTΔ16-YFP reporter in characterizing the dynamics of Nrf2 translocation in response to diverse stimuli. In summary, our innovative reporter system not only revealed compounds capable of modulating UVA-induced Nrf2 activity but also showcased its utility as a robust tool for future antioxidant compound screening efforts.

Use of the Sub Array From Microstrip Elements in Dielectric Layers Before the Aperture of Phased Antenna Array for Impedance Matching at Scanning

The solution of an electrodynamics’ problem of radiation of the Phased antenna array (PAR), representing the infinite periodic structure generated from the open ends of waveguides is offered. Before an aerial aperture sub array from strip (tape) elements in the dielectric layers is installed. The array in the dielectric layers f organizes of strip-geometry elements artificial medium. The problem is reduced to system of the integrated equations of 1-st sort which is decided concerning unknown fields in the aperture of the open ends of waveguides and currents on stripe-geometry elements. In a wide frequency band the numerical analysis of radiation parameters artificial dielectric medium on PAR electrodynamics’ characteristics at beam steering.

The synthesis of VO2(B) ultrathin nanosheets array and effects of optical radiation on room temperature NO2 gas sensing performance

The synthesis of VO2(B) ultrathin nanosheets array and effects of optical radiation on room temperature NO2 gas sensing performance

Overview of algorithms for approximation of the electromagnetic field and synthesis of antenna array radiation patterns

Overview of algorithms for approximation of the electromagnetic field and synthesis of antenna array radiation patterns