Opposite Polarity Research Articles

Electromagnetic lensing using the Aharonov–Bohm effect

We demonstrate theoretically and experimentally an electromagnetic lensing concept using the magnetic vector potential—in a region free of classical electromagnetic fields—via the Aharonov–Bohm (AB) effect. This toroid-shaped lens with poloidal current flow allows for electromagnetic lensing which can be tuned to be convex or concave with a spherical aberration coefficient of opposite polarity to its focal length. This field-free lens combines the advantages of traditional electromagnetic and electrostatic field-based lenses and opens up additional possibilities for the optical design of charged-particle systems. More generally, these results demonstrate that the AB effect can shape charged particle wavefronts beyond simple step shifts if topologies beyond simple flux lines are considered and further supports the physical significance of the magnetic vector potential.

A Hyperactive Geomagnetic Field in the Late Visean (Early Carboniferous) From the Late Asbian Stratotype Section in Northwest England, UK

Plain Language SummaryNearly synchronous global changes in geomagnetic polarity give both a detailed irregular pacing to geological time and provide a glimpse into heat transfer processes across the core—mantle boundary which drives the Earth's geodynamo. Although the Late Carboniferous is characterized by some well‐studied reversals, details of the tempo of polarity changes in the Early Carboniferous are unknown. This work addresses this by providing a detailed record of polarity changes over a ∼2 million year interval at around 334.5–332.5 million years ago‐from the Trowbarrow Quarry section in NW England. We demonstrate that these limestones likely preserve magnetization from close to their time of formation and record at least 31 polarity reversals. These observations support the idea that the Earth's dynamo was in a hyperactive reversing state similar to those sustained for tens of Myr in the Late Jurassic, parts of the Cambrian and the Late Ediacaran. It further corroborates a ∼200 Myr cyclicity in paleomagnetic field behavior since the Precambrian, potentially linked to variable core heat flow forced by mantle convection.

On the Origin of the Sudden Heliospheric Open Magnetic Flux Enhancement During the 2014 Pole Reversal

Coronal holes are recognized as the primary sources of heliospheric open magnetic flux (OMF). However, a noticeable gap exists between in situ measured OMF and that derived from remote-sensing observations of the Sun. In this study, we investigate the OMF evolution and its connection to solar structures throughout 2014, with special emphasis on the period from September to October, where a sudden and significant OMF increase was reported. By deriving the OMF evolution at 1 au, modeling it at the source surface, and analyzing solar photospheric data, we provide a comprehensive analysis of the observed phenomenon. First, we establish a strong correlation between the OMF increase and the solar magnetic field derived from a potential-field source-surface model (cc Pearson = 0.94). Moreover, we find a good correlation between the OMF and the open flux derived from solar coronal holes (cc Pearson = 0.88), although the coronal holes only contain 14%–32% of the Sun’s total open flux. However, we note that while the OMF evolution correlates with coronal hole open flux, there is no correlation with the coronal hole area evolution (cc Pearson = 0.0). The temporal increase in OMF correlates with the vanishing remnant magnetic field at the southern pole, caused by poleward flux circulations from the decay of numerous active regions months earlier. Additionally, our analysis suggests a potential link between the OMF enhancement and the concurrent emergence of the largest active region in solar cycle 24. In conclusion, our study provides insights into the strong increase in OMF observed during 2014 September–October.

The Convincing Cosmic Energy Gravitational Genesis of the Strongest Geomagnatic Anomalies of the Magnetic Field of the Earth

The author presents convincing evidence of the cosmic (planetary and solar) energy gravitational origin (related to the maximal and minimal combined planetary and solar integral energy gravitational influences on the internal rigid core of the Earth) of the maximal temporal intensifications of the global magnetic processes of the Earth. In fairly good agreement with the calculated date 2007.416666666 AD (of the local minimal planetary and solar integral energy gravitational influence on the internal rigid core), it was observed the very rapid changes of the geomagnetic field near the date March 2007 AD (corresponding approximately to 19-20 April 2007 AD). This fairly good agreement gives the additional convincing argument that the date March 2007 AD can be considered as the possible beginning of the geomagnetic reversal during the evaluated range (2007÷2216) AD. The strong magnetic anomaly occurred on 6 January 2020 AD in perfect agreement with the calculated date 2020.016666667 AD (corresponding to 6 January 2020 AD) related to the local maximal planetary and solar integral energy gravitational influence on the internal rigid core. In fairly good agreement with the calculated date 2023.26666666 AD (corresponding approximately to 7 April 2023 AD) of the local maximal planetary and solar integral energy gravitational influence on the internal rigid core, it was observed the strongest (during the last 6 years) magnetic anomaly on 23 March 2023 AD. These convincing agreements demonstrate the physical validity of the established global prediction thermohydrogravidynamic principles, which can be considered as the proven physical basis for the development of the general unified geophysical theory (describing the possible geomagnetic reversal during the evaluated range (2007 ÷ 2216) AD) combining the Special Theory of Relativity, the relativistic electrodynamics and the relativistic theory of the non-stationary gravitation, which can be developed based on the established physical analogy between the established relation for the energy flux (of the gravitational energy) and the Lorentz’s calibration condition (for the vector potential related with the scalar potential of the non-stationary electromagnetic field).

Ultrahigh Energy Storage Density and Efficiency in Orthorhombic PLZST Antiferroelectric Ceramics via Composition Regulation.

PbZrO3-based antiferroelectric (AFE) ceramic materials have emerged as potential candidates for the next generation of high-energy multilayer ceramic capacitors (MLCCs) because of their distinctive characteristics of double hysteresis loops. The energy storage efficiency of orthorhombic AFE ceramics with ultrahigh storage density is relatively low, which hinders their practical application. In this study, the low efficiency limit of PLZST-based orthorhombic ceramics was overcome by precisely adjusting the Sn4+ content in the (Pb0.95Ca0.02La0.02)(Zr0.99-xSnxTi0.01)O3 AFE ceramics. On one hand, the addition of Sn4+ disrupts the original long-range dipole and improves the rapid response of polarization reversal under the applied voltage. As a result, the difference in electric hysteresis under an electric field is reduced, leading to a significant improvement in energy storage efficiency. On the other hand, increasing the Sn4+ content suppresses the formation of oxygen vacancies, inhibiting grain growth and strengthening grain bonding. This results in ceramics with a high breakdown field strength. Ultimately, the resulting PLCZST ceramics reveal an expressively improved recoverable energy density of 10.2 J cm-3 together with a high energy efficiency of 91.4% under a high applied electric field of 560 kV cm-1. The present study demonstrates the tunability of performance in orthorhombic PLZST AFE ceramics, thereby introducing a ceramic material with exceptional energy storage capabilities for MLCC applications.

A novel hybrid method for calculating the fetal heart rate from the non-invasive abdominal Electrocardiogram signal

Continuous monitoring of fetal health requires the accurate calculation of the Fetal Heart Rate (FHR) by efficiently isolating fetal Electrocardiogram (fECG) from non-invasive abdominal Electrocardiogram (aECG). There are numerous solutions proposed for this problem, having its own restrictions. This paper introduces a novel three-stage hybrid adaptive approach for fECG extraction and FHR determination from aECG. The proposed framework is an amalgamation of independent component analysis (ICA), adaptive exponential functional link network (AEFLN), and novel wavelet thresholding (NWT). The proposed work aims to determine the best quality fetal R-peaks for calculating fetal heart rate (FHR). ICA is a blind source separation technique that uses all the information from the multichannel inputs to determine the maternal Electrocardiogram (mECG) and enhanced aECG. In the next stage, a non-linear adaptive filter, AEFLN, is used for the extraction of fECG. This approach requires no additional algorithm for polarity reversal and time alignment before AEFLN. At last, NWT determines the fetal R-peak envelopes from the residual fECG. The R-peak envelopes are used to analyze FHR, and its accuracy was accessed using the FHR trace. So far, FastICA-AEFLN-NWT has not been used as a hybrid method for fECG extraction and fetal R-peak detection. The algorithm’s effectiveness was tested on both real databases from Daisy and Physionet and synthetic databases from Physionet. The proposed hybrid method attains 95.29 % of sensitivity (SE), 96.68 % of Positive Predictive Value (PPV), 95.92 % of F1 score, and FHR measurement (FHRmeas) is 29.72 bpm2. The proposed methodology outperforms the state-of-art methods in fECG extraction.

Abstract 2796: Colibactin mutation signatures are associated with younger age of onset in colorectal cancer

Abstract Escherichia coli (E. coli) strains carrying the polyketide synthase (pks) island produce the genotoxin colibactin associated with pathogenesis of colorectal cancer (CRC). Colibactin binds directly to DNA, causing alkylating damage leading to double stranded DNA breaks. Colibactin mutagenesis results in mutations in hexameric A-T rich DNA motifs that can be identified by whole genome sequencing (WGS) as mutation signatures SBS28 and SBS88 (SBS-pks). Since WGS is not routinely used clinically, we developed an approach to specifically identify SBS-pks using a clinical targeted exon capture assay, MSK-IMPACT. In an institutional pan-cancer clinical cohort of 78,905 tumors we identified 15,967 samples with > 20 mutations detected by MSK-IMPACT. We identified 150/1,884 samples with microsatellite stable CRC with >10% mutations attributable to SBS-pks. Examining clinicopathologic and genomic features of SBS-pks+ compared to SBS-pks- CRC tumors, we found that SBS-pks+ signatures are significantly enriched in younger age of onset compared to SBS-pks- CRC patients (median age 55 vs median age 59, p= 0.0028). SBS-pks+ CRC exhibit similar driver mutations and tumor mutational burden (TMB) compared to SBS-pks- CRC but are associated with increased fraction of genome altered (FGA). To mechanistically investigate colibactin-associated damage we developed a novel long-term human colon organoid-microbe co-culture model system that takes advantage of reversal of polarity in suspension culture. WGS of human CRC organoids co-cultured for three months with pks+ and delta-pks E. coli NC101 confirmed induction of pks+ specific SBS-pks signatures, validating the model. Leveraging this model and a biobank of normal colon organoids from donors aged </> 50 years, we are investigating the molecular mechanisms underlying the association of SBS-pks with younger age of onset CRC. Citation Format: Stefanie Gerstberger, Melissa Lumish, Saskia Hartner, Farheen Shah, Seongmin Choi, Anisha Luthra, Qingwen Jiang, Hyung Jun Woo, Ahmed Mahmoud, Henry Walch, Simran Asawa, Mark Donoghue, Andrea Cercek, Rona Yaeger, Andrew McPherson, Francisco Sanchez-Vega, Karuna Ganesh. Colibactin mutation signatures are associated with younger age of onset in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2796.

New volcanological, 40Ar/39Ar dating and paleomagnetic record from Trindade Island and stratigraphic implications

Unrevealing the stratigraphy of volcanic systems is fundamental to understanding their eruptive history and requires a multiproxy approach for the accurate correlation and interpretation of deposits. We present new volcanological, 40Ar/39Ar ages and paleomagnetic data from the volcanic rocks of Trindade Island, located at ∼1.260 km from the Brazilian coast in the South Atlantic Ocean. The reconstruction of the volcanic history of Trindade Island is important because it is the youngest volcanic terrain in Brazil and part of a submarine chain that represents the most recent plume-induced alkaline manifestation beneath the South American plate. Our results suggest Trindade Island underwent two main phases of volcanism. The first phase (3.9–1.5 Ma) formed the Trindade Complex and Desejado Formation, with eruptive styles ranging from phreatomagmatic/Surtseyan to Vulcanian and of dominant phonolitic composition. The second phase (1.0–0.06 Ma) formed the nephelinitic monogenetic centers Morro Vermelho, Valado and Paredão Volcano Formations through dominant Hawaiian and Strombolian styles. The new ages imply a revised stratigraphy for the youngest units of Trindade Island, with partial overlap between them. The revised chronology integrated to the paleomagnetic directional data evidence that Trindade Complex formed during Gauss normal chron (D = 355.4°; I = −49.6°), Valado and Paredão Volcano during Brunhes normal chron (D = 14°; I = −42.3° and D = 9.2°; I = −35.2°, respectively), while Morro Vermelho records the late Matuyama-early Brunhes chron (D = 36.5°; I = −19.8°), with site-level mean paleodirections of normal and transitional polarity within the reverse Matuyama interval.

Understanding of polarization reversal and charge trapping under imprint in HfO2-FeFET by charge component analysis

Polarization reversal and charge trapping under imprint in HfO2-based ferroelectric FET (FeFET) are studied by charge component analysis. By decomposing the effects of spontaneous polarization and charge trapping using the transient current measurement with triangle waves in both metal–ferroelectric–metal (MFM) and metal–ferroelectric–insulator-Si (MFIS) capacitors, we found that V th under imprint in MFIS is determined by both coercive voltage (V c) shift due to imprint and the subsequent modulation of charge trapping at the same polarization. In addition, a comparison of V c shift due to imprint of MFM and MFIS was performed. V c shift of MFIS was found to be in good agreement with that of MFM. This implies that the imprint in FeFET can be predicted from MFM even though FeFET has a complex structure with an interfacial layer.

Heteroatom-doped fluoride interphase enables rapid ion conduction for highly stable zinc metal batteries

Interlayer protection can effectively suppress zinc (Zn) dendrite growth, but suffers from sluggish Zn2+ conduction and anti-corrosion instability, which causes high polarization and inferior reversibility, hindering the practical applications of Zn metal batteries. Herein, we propose a heteroatom-dopant strategy for atomically-level regulation of fluoride interlayer to synchronously circumvent the above two issues. With a facile growth-doping approach, uniform phosphorus-doped ZnF2 (P-ZnF2) layer is grown on the surface of Zn foil. Experimental characterizations and computational analyses both demonstrate the doping of P atoms into ZnF2 lattice not only accelerates Zn2+ conduction across the interlayer, but also enhances the interlayer stability for durable protection. Consequently, the P-ZnF2 layer realizes a high reversibility with an average Coulombic efficiency of 99.5% and an impressive lifespan over 4200 h in symmetric cell. More encouragingly, the superior kinetics of stable P-ZnF2 achieves outstanding stability under rather demanding conditions: stable cycling over 4000 cycles at an ultrahigh current density of 50 mA cm–2; 320 h of lifespan with 91% of Zn utilization rate; 650 h of prolonged cycling behavior at a high temperature of 60 °C. Furthermore, the assembled full cell corroborates the practical feasibility of P-ZnF2 layer, even under an ultrahigh mass loading of cathode.

Deciphering cellular and molecular mechanism of MUC13 mucin involved in cancer cell plasticity and drug resistance.

There has been a surge of interest in recent years in understanding the intricate mechanisms underlying cancer progression and treatment resistance. One molecule that has recently emerged in these mechanisms is MUC13 mucin, a transmembrane glycoprotein. Researchers have begun to unravel the molecular complexity of MUC13 and its impact on cancer biology. Studies have shown that MUC13 overexpression can disrupt normal cellular polarity, leading to the acquisition of malignant traits. Furthermore, MUC13 has been associated with increased cancer plasticity, allowing cells to undergo epithelial-mesenchymal transition (EMT) and metastasize. Notably, MUC13 has also been implicated in the development of chemoresistance, rendering cancer cells less responsive to traditional treatment options. Understanding the precise role of MUC13 in cellular plasticity, and chemoresistance could pave the way for the development of targeted therapies to combat cancer progression and enhance treatment efficacy.

Optical Modulation of MoTe2/Ferroelectric Heterostructure via Interface Doping.

Optical modulation through interface doping offers a convenient and efficient way to control ferroelectric polarization, thereby advancing the utilization of ferroelectric heterostructures in nanoelectronic and optoelectronic devices. In this work, we fabricated heterostructures of MoTe2/BaTiO3/La0.7Sr0.3MnO3 (MoTe2/BTO/LSMO) and demonstrated opposite ultraviolet (UV) light-induced polarization switching behaviors depending on the varied thicknesses of MoTe2. The thickness-dependent band structure of MoTe2 film results in interface doping with opposite polarity in the respective heterostructures. The polarization field of BTO interacts with the interface charges, and an enhanced effective built-in field (Ebi) can trigger the transfer of massive UV light-induced carriers in both MoTe2 and BTO films. As a result, the interplay among the contact field of MoTe2/BTO, the polarization field, and the optically excited carriers determines the UV light-induced polarization switching behavior of the heterostructures. In addition, the electric transport characteristics of MoTe2/BTO/LSMO heterostructures reveal the interface barrier height and Ebi under opposite polarization states, as well as the presence of inherent in-gap trap states in MoTe2 and BTO films. These findings represent a further step toward achieving multifield modulation of the ferroelectric polarization and promote the potential applications in optoelectronic, logic, memory, and synaptic ferroelectric devices.

Microcurrent-Mediated Modulation of Myofibroblasts for Cardiac Repair and Regeneration.

Cardiovascular diseases are a significant cause of illness and death worldwide, often resulting in myofibroblast differentiation, pathological remodeling, and fibrosis, characterized by excessive extracellular matrix protein deposition. Treatment options for cardiac fibrosis that can effectively target myofibroblast activation and ECM deposition are limited, necessitating an unmet need for new therapeutic approaches. In recent years, microcurrent therapy has demonstrated promising therapeutic effects, showcasing its translational potential in cardiac care. This study therefore sought to investigate the effects of microcurrent therapy on cardiac myofibroblasts, aiming to unravel its potential as a treatment for cardiac fibrosis and heart failure. The experimental design involved the differentiation of primary rat cardiac fibroblasts into myofibroblasts. Subsequently, these cells were subjected to microcurrent (MC) treatment at 1 and 2 µA/cm2 DC with and without polarity reversal. We then investigated the impact of microcurrent treatment on myofibroblast cell behavior, including protein and gene expression, by performing various assays and analyses comparing them to untreated myofibroblasts and cardiac fibroblasts. The application of microcurrents resulted in distinct transcriptional signatures and improved cellular processes. Gene expression analysis showed alterations in myofibroblast markers, extracellular matrix components, and pro-inflammatory cytokines. These observations show signs of microcurrent-mediated reversal of myofibroblast phenotype, possibly reducing cardiac fibrosis, and providing insights for cardiac tissue repair.

Domain Dynamics and Resistive Switching in Ferroelectric Al1–xScxN Thin Film Capacitors

AbstractIn this paper, using a combination of pulse testing measurements and piezoresponse force microscopy (PFM), an investigation of the polarization reversal behavior and the accompanying resistive switching in the Al0.72Sc0.28N thin film capacitors is reported. The obtained results reveal a transition from the nucleation‐limited switching (NLS) in the low field range toward the more uniform switching described by the Kolmogorov–Avrami–Ishibashi (KAI) model in the high field range. It is found that the Al0.72Sc0.28N capacitors exhibit an unusually steep change in the switching time– it decreases by five orders of magnitude with a moderate increase of the applied field. This feature is caused by a significantly higher activation field value (≈126 MV cm−1) in comparison with the conventional perovskite ferroelectrics. PFM visualization of the field‐induced domain dynamics has allowed the evaluation of the nucleation rate and domain wall velocity. Furthermore, capacitors in the polydomain state generated by partial switching of polarization exhibit a significant (up to two orders of magnitude) increase in the steady‐state conductance. This effect is likely caused by the injection of strongly inclined conducting 180° domain walls. Resistance tunability offers additional functionalities to the Al1‐xScxN devices where conductive domain walls are used as active elements.

Exosome circATP8A1 induces macrophage M2 polarization by regulating the miR-1-3p/STAT6 axis to promote gastric cancer progression

Circular RNAs (circRNAs) play important roles in gastric cancer progression but the regulatory role of circRNAs in controlling macrophage function remains elusive. Exosomes serve as cargo for circRNAs and play a crucial role as mediators in facilitating communication between cancer cells and the tumor microenvironment. In this study, we found that circATP8A1, a previously unreported circular RNA, is highly expressed in both gastric cancer tissues and exosomes derived from plasma. Increased circATP8A1 was associated with advanced TNM stage and worse prognosis in patients with gastric cancer. We showed that the circATP8A1 knockdown significantly inhibited gastric cancer proliferation and invasion in vitro and in vivo. Functionally, exosome circATP8A1 induced the M2 polarization of macrophages through the STAT6 pathway instead of the STAT3 pathway. Mechanistically, circATP8A1 was shown to activate the STAT6 pathway through competitive binding to miR-1-3p, as confirmed by Fluorescence In Situ Hybridization (FISH), RNA immunoprecipitation, RNA pulldown, and Luciferase reporter assays. The reversal of circATP8A1-induced STAT6 pathway activation and macrophage polarization was observed upon blocking miR-1-3p. Macrophages treated with exosomes from gastric cancer cells overexpressing circATP8A1 were able to promote gastric cancer migration, while knockdown of circATP8A1 reversed these effects in vivo. In summary, exosome-derived circATP8A1 from gastric cancer cells induce macrophages M2 polarization via the circATP8A1/miR-1-3p/STAT6 axis, and tumor progression. Our results highlight circATP8A1 as a potential prognostic biomarker and therapeutic target in gastric cancer.

Magnetorheological Polishing Based on Honing Vertical Mechanism for Inner Surface of Titanium Alloy Pipes

Recently, high internal surfaces for titanium alloy pipes have been required due to the increment of various applications such as aerospace components. In this work, vertical magnetorheological polishing (VMRP) is carried out to achieve high polishing performance on the internal surface of the titanium alloy pipe. A series of comparative experiments were conducted to investigate the polishing mechanism of magnetorheological polishing (MRP) fluid and enhance the polishing performance. It is shown from the experimental results that the VMRP method under the opposite polarity arrangement improves the surface roughness from 47.85% to 83.34% by reducing unwanted vibration and noise during operation. This provides nanoscale surface polishing quality, while such a precision cannot be achieved from the previous horizontal MR polishing apparatus method. It is found that under a 2700 cycle polishing time, a polishing process combining a rough and fine polishing approach with a combination of different particle diameters results in an axial surface roughness of 0.05 μm and circumferential surface roughness of 0.038 μm, respectively. It is also identified that the axial surface roughness of 0.04 μm–0.041 μm is achieved through the combination of high- and low-speed polishing process after 1602 cycles.

Universal responses in nonmagnetic polar metals

We demonstrate that two phenomena, the kinetic magnetoelectric effect and the nonlinear Hall effect, are universal to polar metals as a consequence of their coexisting and contraindicated polarization and metallicity. We show that measurement of the effects provides a complete characterization of the nature of the polar metal, in that the nonzero response components indicate the direction of the polar axis, and the coefficients change signs on polarization reversal and become zero in the nonpolar phase. We illustrate our findings for the case of electron-doped PbTiO3 using a combination of density functional theory and model Hamiltonian-based calculations. Our model Hamiltonian analysis provides crucial insight into the microscopic origin of the effects, showing that they originate from inversion-symmetry-breaking-induced interorbital hoppings that correlate to an asymmetric charge density quantified by odd-parity charge multipoles. Our paper both heightens the relevance of the kinetic magnetoelectric and nonlinear Hall effects, and broadens the platform for investigating and detecting odd-parity charge multipoles in polar metals. Published by the American Physical Society 2024

An analytical approach to engineer multistability in the oscillatory response of a pulse-driven ReRAM

A nonlinear system, exhibiting a unique asymptotic behaviour, while being continuously subject to a stimulus from a certain class, is said to suffer from fading memory. This interesting phenomenon was first uncovered in a non-volatile tantalum oxide-based memristor from Hewlett Packard Labs back in 2016 out of a deep numerical investigation of a predictive mathematical description, known as the Strachan model, later corroborated by experimental validation. It was then found out that fading memory is ubiquitous in non-volatile resistance switching memories. A nonlinear system may however also exhibit a local form of fading memory, in case, under an excitation from a given family, it may approach one of a number of distinct attractors, depending upon the initial condition. A recent bifurcation study of the Strachan model revealed how, under specific train stimuli, composed of two square pulses of opposite polarity per cycle, the simplest form of local fading memory affects the transient dynamics of the aforementioned Resistive Random Access Memory cell, which, would asymptotically act as a bistable oscillator. In this manuscript we propose an analytical methodology, based on the application of analysis tools from Nonlinear System Theory to the Strachan model, to craft the properties of a generalised pulse train stimulus in such a way to induce the emergence of complex local fading memory effects in the nano-device, which would consequently display an interesting tuneable multistable oscillatory response, around desired resistance states. The last part of the manuscript discusses a case study, shedding light on a potential application of the local history erase effects, induced in the device via pulse train stimulation, for compensating the unwanted yet unavoidable drifts in its resistance state under power off conditions.

Absorption-transmission-diffusion-type radar cross section reduction metasurfaces based on frequency selective absorber and polarization conversion chessboard structure

Absorption-transmission-diffusion-type radar cross section (RCS) reduction metasurfaces based on the frequency selective absorber and the polarization conversion chessboard structure are proposed in this paper. The RCS reduction metasurfaces consist of three parts, i.e. the top layer realized by a cross-shaped meander line loaded with lumped resistors for low-frequency absorption and high-frequency transmission, the mid-layer constructed by angular ring vias frequency selective surface (FSS) sandwiched with two square patches FSS for broadband transmission in mid-frequency zone, and the bottom layer employed chessboard metasurfaces composed of dual-arrow type polarization conversion units for scattering cancellation in high frequency zone. The physical mechanisms of the RCS reduction metasurfaces with multifunctional electromagnetic controlling including wave absorption, bandpass transmission, polarization reversal, and phase cancellation are also discussed and analyzed. Simulation and experimental results demonstrate a reflection of lower than −10 dB for normal incident linearly polarized waves over a frequency range of 2.5 GHz–18 GHz, with a relative bandwidth of 151.22%; transmission passband properties with insertion loss better to −3 dB in the frequency range of 5.62 GHz–11.0 GHz, with a relative bandwidth of 64.74%. Due to the resonance-coupling-resonance principle, the broadband transmission with low insertion loss was obtained. The RCS properties of the proposed multi-functional metasurfaces were further analyzed by numerical simulation and experimental measurement, and the results showed that RCS reduction of over 10 dB was achieved for normal incident different polarized waves at the frequency range of 2.5 GHz to 17 GHz. Even in the case of normal incidence, there was a deviation between the reflection characteristics and RCS reduction. The RCS reduction metasurfaces are expected to be employed in applications where multi mechanism collaborative control of electromagnetic waves is of extreme importance.

Investigation of the large-signal electromechanical behavior of ferroelectric HfO2–CeO2 thin films prepared by chemical solution deposition

Investigation of the large-signal electromechanical behavior of ferroelectric HfO2–CeO2 thin films prepared by chemical solution deposition