Electromagnetic Science最新文献

{"title":"Improving Radiation Pattern Roundness of Henge-Like Metaring-Loaded Monopoles Above a Finite Ground for MIMO Systems","authors":"Bo Zhang;Zhi Ning Chen;Yucong Zhou;Qun Lou;Jiahao Wang;Koen Mouthaan","doi":"10.23919/emsci.2024.0018","DOIUrl":"https://doi.org/10.23919/emsci.2024.0018","url":null,"abstract":"A henge-like metaring (HMR) is proposed for improving the radiation pattern roundness of monopole antennas off-center mounted on a finite ground by localizing the radiation from the monopole and suppressing the scattering by the ground. The improved patterns enhance uniform coverage of multiple-input and multiple-output (MIMO) systems. The study reveals that the radiation pattern of an off-center monopole is distorted by the asymmetric ground currents excited by both the feed and the radiation of the monopole. The distorted radiation patterns severely degrade wireless communication link quality. The HMR, composed of an annular array of mushroom unit cells, simultaneously functions as an electromagnetic bandgap (EBG) and a radiator, and encircles the monopole to form a henge monopole antenna (HMA). The HMR as an EBG is used to suppress the ground currents outside the HMR analyzed by an equivalent circuit model. The HMR as a radiator is designed to decouple the monopole from the ground with its elevated radiation pattern using characteristic mode analysis. As examples, two prototypes of single and four off-center MIMO HMAs are designed and investigated in the 2.45-GHz band. Simulated and measured results show that the single HMA and each of the four HMAs achieve the un-roundness of the radiation pattern at θ = 65° plane lower than 2 dB and 3 dB in the 2.45-GHz band. As a result, near the radiation nulls, the SNR is improved by 6 dB. The compact construction and efficient current suppression facilitate the application of HMAs in multi-antenna systems above a finite ground with uniform coverage and reliable connections.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 2","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10636178","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication and Application of Nano-SQUID Magnetometer to Scanning Imaging of Two-Dimensional Quantum Materials","authors":"Bingke Xiang;Yihua Wang;Hao Li;Shane A. Cybart","doi":"10.23919/emsci.2024.0013","DOIUrl":"https://doi.org/10.23919/emsci.2024.0013","url":null,"abstract":"Superconducting quantum interference devices (SQUIDs) are directly sensitive to magnetic flux. Nano-fabricated SQUID chip with miniaturized superconducting circuits can be further utilized as scanning probes for imaging of materials. Scanning SQUID microscopy (SSM) combines both high spatial resolution and high magnetic field sensitivity and is especially suitable for studying low dimensional materials with small sensing volumes. Here, we briefly review the fabrication of different types of nano-SQUIDs and the recent progress of utilizing them for scanning microscopy of quantum materials. We focus on but are not limited to topological states, unconventional superconductivity and exotic magnetism with a particular interest in two-dimensional materials. The magnetometry, susceptometry and current imaging modes of the SSM coupled with the external tuning of the material by magnetic field, electrical field gating and strain reveals a multitude of information beyond the scopes of charge-sensing probes.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 2","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10636180","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequency-Self-Adaptive Radio Frequency Power Harvester Enabled by Shape-Reconfigurable Liquid Metal","authors":"Cheng Zhang;Yuchao Wang;Zebin Zhu;Hai Lin;Kun Wang;Xintong Shi;Yi Du;Chaoyun Song;Long Ren;Qiang Cheng","doi":"10.23919/emsci.2024.0008","DOIUrl":"https://doi.org/10.23919/emsci.2024.0008","url":null,"abstract":"Radio frequency (RF) energy harvester as an efficient tool for capturing and converting the flourishing ambient RF energy provides a promising solution for long-term powering the wireless sensor networks and the Internet of things (IoTs). However, the actual distribution of the environmental RF signals is dynamically frequency-dependent due to the diverse wireless terminals only interacting with specified frequencies. To take full advantage of the RF energy carrying this characteristic, an intelligent RF energy harvester is in demand to automatically sense the frequency information of an incident signal and conduct the corresponding RF-to-direct current transformation process. Here, to the best of my knowledge, a frequency-self-adaptive RF harvester is first presented with the help of the shape-reconfigurable liquid metal, which can precisely identify and efficiently convert an arbitrary signal from the frequency span of 1.8 to 2.6 GHz. Companied with a microcontroller unit and a tensile system, the dynamic functionality of the entire system is comprehensively demonstrated, showing promising potential to significantly advance various fields, including sustainable IoT applications, green wearable technologies, and self-powered devices.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 2","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10636179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review Antenna Design for Modern Mobile Phones: A Review","authors":"Yan Wang;Libin Sun;Zhengwei Du;Zhijun Zhang","doi":"10.23919/emsci.2023.0052","DOIUrl":"https://doi.org/10.23919/emsci.2023.0052","url":null,"abstract":"Due to limited antenna space, high communication requirements, and strict regulatory constraints, the design of antennas for modern mobile phones has become an exceedingly challenging task. In recent years, numerous studies have been conducted in this area, leading to significant advancements. This review paper comprehensively summarizes recent progress made in antenna design for modern mobile phones. Firstly, the challenges faced in antenna design for modern mobile phones are described, including bandwidth enhancement, integration and decoupling techniques, mm-wave array antennas, satellite communication antennas, as well as interactions between mobile antennas and the human body. Secondly, the basic antenna types (such as inverted-F, slot, loop, and planar inverted-F antennas) commonly used in modern metal-bezel mobile phones along with their key characteristics are briefly summarized. Thirdly, the commonly exployed methods used in practical applications for designing wideband antennas within compact sizes and achieving decoupling among multiple antennas with wide bandwidths are collected. Fourthly, recent advances in the design of compact, wideband, and wide-angle scanning mm-wave arrays for modern mobile phones are summarized. Fifthly, recent progress made in satellite communication antenna designs for modern mobile phones, including broadside and end-fire radiation patterns, is presented. Sixthly, recent studies on the interaction between mobile antennas and the human body are briefly concluded. Finally, the future challenge of antenna design for mobile phones is briefly discussed. It is our hope that this comprehensive review will provide readers with a systematic understanding of antenna design principles applicable to modern mobile phones.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 2","pages":"1-36"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10636175","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superdirective Circular Arrays of Electric and Huygens Dipole Elements","authors":"Richard W. Ziolkowski","doi":"10.23919/emsci.2024.0007","DOIUrl":"https://doi.org/10.23919/emsci.2024.0007","url":null,"abstract":"Uniform circular arrays (UCAs) provide both omnidirectional (360°) and directive (sector) coverage of the azimuthal plane. Superdirective versions with unidirectional, high front-to-back ratio (FTBR) properties could provide the radiated field characteristics being pursued for NextG wireless networks and their perceived applications. Typical UCA configurations - full, semi-circular, and sector - that radiate vertically-polarized (VP) fields and are composed of either omnidirectional electric dipole elements or unidirectional Huygens dipole elements are analyzed first with conventional methods as reference cases. These omni- and uni-directional element configurations are then treated with several optimization techniques: the classic Rayleigh-quotient (RQ) method and its unidirectional-constrained version; the eigenbeam decomposition and synthesis (EBDS) technique used to design superdirective acoustic receiving arrays; and the Bessel-azimuthal multipole (BEAM) approach developed herein. Several arrays are identified as being superdirective with extremely high FTBR values. The performance characteristics of the arrays of unidirectional elements are demonstrated to be superior in general. Moreover, it is shown that larger radius arrays with RQ-specified excitation amplitudes are robust to changes in them whereas the outcomes of the corresponding small radius versions are not. On the other hand, the BEAM-optimized densely-packed small-radius superdirective arrays are quite tolerant to those variations while generating unidirectional pseudo-needle beams.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 1","pages":"1-25"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577280","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time Modulated Array Antennas: A Review","authors":"Wen Wu;Qiaoyu Chen;Jin-Dong Zhang;Tongde Huang;Da-Gang Fang","doi":"10.23919/emsci.2023.0043","DOIUrl":"https://doi.org/10.23919/emsci.2023.0043","url":null,"abstract":"Time-modulated array (TMA) antennas, introduce the dimension of time into antenna design to control the radiation patterns and frequency spectral characteristics, thus improve the reconfigurability of array antennas and provide multiple functionalities. They have great application potential in military and civilian fields, such as precision guidance and mobile communication, and are currently a hot spot of academic research. This article provides a review on the fundamentals and applications of TMAs. First, the basic theory and mathematical formulations of TMAs are introduced. Second, the most important applications of TMAs, namely time-modulated phased arrays (TMPA), are discussed from the perspectives of harmonic suppression and harmonic utilization, which are used for single-beam and multibeam radiation. Then, we survey the combination of TMA with various types of novel antenna arrays, such as single-channel digital beamforming (DBF) arrays, frequency diverse arrays (FDAs), and retrodirective arrays, to create new hardware implementation methods and enhance their performance. Next, recent advances in dedicated integrated chips for TMA, which have played a significant role in driving the progress of TMAs from academic research to practical applications, are presented. Finally, the challenges and prospects for TMAs are discussed, including new research directions and emerging application scenarios.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 1","pages":"1-19"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Fe Substitution on Magnetic Properties and Radar Wave Absorption of the $mathbf{Y}_{mathbf{2}}mathbf{Co}_{mathbf{17}}$ Rare Earth Soft Magnetic Alloy","authors":"Chengfa Tu;Liang Qiao","doi":"10.23919/emsci.2023.0037","DOIUrl":"https://doi.org/10.23919/emsci.2023.0037","url":null,"abstract":"The rapid development of information technology leads a demand for high frequency soft magnetic materials with exceptional radar wave absorption properties. A new magnetic material with superior radar wave absorption is explored in this paper. we explored the preparation of \u0000<tex>$mathrm{Y}_{2}text{Co}_{17-x}text{Fe}_{x} (x=0.0,1.0,2.0,3.0)$</tex>\u0000 alloy powders using yttrium oxide as a raw material by a low-cost and short preparation cycle reduction-diffusion process. The crystal structure, intrinsic magnetic properties, high frequency magnetism and radar wave absorption of \u0000<tex>$mathrm{Y}_{2}text{Co}_{17-x}text{Fe}_{x}(x=0.0, 1.0,2.0,3.0)$</tex>\u0000 were investigated. These compounds have a perfect magnetic repair of \u0000<tex>$mathrm{Y}_{2}text{Co}_{17}$</tex>\u0000 and enable the improvement of the overall magnetic properties of \u0000<tex>$mathrm{Y}_{2}text{Co}_{17-x}text{Fe}_{x} (x=0.0,1.0,2.0,3.0)$</tex>\u0000 compounds. The \u0000<tex>$mathrm{Y}_{2}text{Co}_{17-x}text{Fe}_{x}$</tex>\u0000 /Polyurethane (PU) \u0000<tex>$(x=0.0, 1.0,2.0,3.0)$</tex>\u0000 absorbers were divided in detail using the zero-reflection mechanism. The results show that all \u0000<tex>$mathrm{Y}_{2}text{Co}_{17-mathrm{x}}text{Fe}_{x}/text{PU}(x=0.0,1.0,2.0,3.0)$</tex>\u0000 absorbers have excellent absorption performance (reflection loss RL is less than -85 dB); in addition, \u0000<tex>$mathrm{Y}_{2}text{Co}_{15}text{Fe}_{2}/text{PU}$</tex>\u0000 absorbers and \u0000<tex>$mathrm{Y}_{2}text{Co}_{14}text{Fe}_{3}/text{PU}$</tex>\u0000 absorbers are superior candidates for S-band materials. In particular, the perfectly matched frequency \u0000<tex>$f_{mathrm{p}}$</tex>\u0000 of the modulated \u0000<tex>$mathrm{Y}_{2}text{Co}_{14}text{Fe}_{3}/text{PU}$</tex>\u0000 absorber is shifted to the L-band (1–2 GHz) where early warning radars are located. The \u0000<tex>$mathrm{Y}_{2}text{Co}_{14}text{Fe}_{3}/text{PU}$</tex>\u0000 absorber has an effective absorption bandwidth of 300 MHz (1.5-1.8 GHz) at a thickness of 5.230 mm. It can also absorb the full L-band at -4 dB, which has rarely been reported.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577279","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequency-Diversified Space-Efficient Radiating Surface Using Convolved Electric and Magnetic Currents for Highly Dense Multiband Antenna-Frontend Integration","authors":"Amirhossein Askarian;Pascal Burasa;Ke Wu","doi":"10.23919/emsci.2023.0021","DOIUrl":"https://doi.org/10.23919/emsci.2023.0021","url":null,"abstract":"We propose and investigate a methodology based on convolved electric and magnetic currents for the generation of multi-band responses over a space-shared radiating surface. First, a single wideband antenna operation principle based on interleaved dipole and slot modes is studied and analyzed using full-wave simulations followed by a qualitative time domain analysis. Subsequently, a \u0000<tex>$2times 2$</tex>\u0000 dual-band radiating unit is conceived and developed by closely arranging single wideband antennas. In this case, multimode resonances are generated in a lower frequency band by a proper convolving and coupling of the magnetic and electric currents realized in the gaps between the antennas and on the surface of the antennas, respectively. This methodology can be deployed repeatedly to build up a self-scalable topology by reusing the electromagnetically (EM) connected radiating surfaces and gaps between the radiating units. Due to the efficient reuse of the electromagnetic region for the development of multiband radiation, a high aperture-reuse efficiency is achieved. Finally, as a proof of concept, a \u0000<tex>$2times 4$</tex>\u0000 dual-band array operating in Ku- and Ka-bands is developed and fabricated by a linear arrangement of the two developed radiating units. Our measurement results show that the proposed antenna array provides impedance and gain bandwidths of 30% and 25.4% in the Ku-band and 10.65% and 8.52% in the Ka-band, respectively.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalized Odd-Even Mode Theory and Mode Synthesis Antenna Design Approach","authors":"Wen-Jun Lu","doi":"10.23919/emsci.2023.0044","DOIUrl":"https://doi.org/10.23919/emsci.2023.0044","url":null,"abstract":"In this article, studies on the multimode excitation problem of waveguides and antennas, the balance/unbalance mechanism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed. In this context, generalized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna. As is mathematically deduced and demonstrated, the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems. Thus, an elegant, closed-form formula is derived to approximately calculate the “unbalance degree” of a straight dipole off-center fed by a symmetric twin-wire line. Design approaches for the simplest, linear, 1-D multimode resonant antennas are introduced. Moreover, the “falling tone excitation” law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas (MPAs) and 2-D sectorial electric dipole antennas. Design examples with distinctive radiation performance are presented and discussed. Finally, possible development trends of multimode resonant antennas are prospected.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"2 1","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sub-Gridding FDTD Algorithm for 3D Numerical Analysis of EM Scattering and Radiation Problems","authors":"Fatih Kaburcuk;Atef Z. Elsherbeni","doi":"10.23919/emsci.2023.0034","DOIUrl":"https://doi.org/10.23919/emsci.2023.0034","url":null,"abstract":"The finite-difference time-domain (FDTD) method is used effectively to solve electromagnetic (EM) scattering and radiation problems using a 3D sub-gridding algorithm. For accuracy and stability of the FDTD method, the computational domain of EM problems with locally fine structures or electrically small objects is discretized with finer grids. This sub-gridding algorithm for different regions of the computational domain was implemented to increase the accuracy and reduce the computational time and memory requirements compared to those of the traditional FDTD method. In the sub-gridding algorithm, the FDTD computational domain is divided into separate regions: coarse grid and fine grid regions. Since the cell sizes and time steps are different in the coarse and fine grid regions, interpolations in both time and space are used to evaluate the electric and magnetic fields on the boundaries between different regions. The accuracy of the developed 3D sub-gridding algorithm has been verified for radiation and scattering problems, including multiple fine grid regions. Excellent performance is obtained even for higher and different contrast ratios in fine grid regions.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 4","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10433553","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139732018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}