{"title":"A Frequency Tunable Liquid Cavity Bandpass Filter","authors":"Guoxuan Zhang;Lei Xing;Qian Xu;Yongjiu Zhao;Chaoyun Song;Yi Huang","doi":"10.23919/emsci.2022.0006","DOIUrl":"https://doi.org/10.23919/emsci.2022.0006","url":null,"abstract":"A liquid-loaded frequency tunable cavity bandpass filter (BPF) is presented. A dielectric fluidic material, dimethyl silicone oil (DSO) with excellent thermophysical characteristics (working temperature from -50 °C to 180 °C) and extremely low loss tangent is employed as a dielectric loading. The frequency reconfigurability of the proposed design is realized by altering the liquid level inside the cavity resonator. The filter achieves a wide frequency tuning range as well as a high Q factor. Moreover, this design shows significantly improved environmental suitability in extreme temperature cases, outperforming the existing microfluidic-based RF devices using water or liquid metals. A four-pole tunable cavity bandpass filter is designed and verified. A cross-coupling structure comprising a metal loop structure is used to introduce transmission zeros in the proposed filter, which enhances the skirt selectivity and out-of-band rejections. We demonstrate that the center frequency of the proposed BPF can be tuned from 4.92 GHz to 6.16 GHz, and the filter achieves a high Q factor between 521 and 1527. The measured results agree well with simulated results.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 2","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10226314/10238369.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50280334","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}
Bin Zheng;Huan Lu;Chao Qian;Dexin Ye;Yu Luo;Hongsheng Chen
{"title":"Revealing the Transformation Invariance of Full-Parameter Omnidirectional Invisibility Cloaks","authors":"Bin Zheng;Huan Lu;Chao Qian;Dexin Ye;Yu Luo;Hongsheng Chen","doi":"10.23919/emsci.2023.0009","DOIUrl":"https://doi.org/10.23919/emsci.2023.0009","url":null,"abstract":"Searching for an optimal solution among many nonunique answers provided by transformation optics is critical for many branches of research, such as the burgeoning research on invisibility cloaks. The past decades have witnessed rapid development of transformation optics, and different kinds of invisibility cloaks have been designed and implemented. However, the available cloaks realized thus far have been mostly demonstrated with reduced parameters, which greatly impact the predefined cloaking performance. Here, we report a general design strategy to realize full-parameter omnidirectional cloaks that can hide arbitrarily shaped objects in free space. Our approach combines a singular transformation with transformation-in-variant metamaterials. The cloaking device with extreme parameters is implemented using a metallic array structure. In the experiment, two cloak samples are designed and fabricated, one with nondiscrete cloaking regions and the other with separated hidden regions. Near-unit transmission of electromagnetic waves with arbitrary incident angles is experimentally demonstrated along with significantly suppressed scattering. Our work challenges the prevailing paradigms of invisibility cloaks and provides deep insight into how transformation optics could be harnessed to obtain easily-accessible metadevices.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 2","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10226314/10238371.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50402284","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}
Jianwei You;Qian Ma;Lei Zhang;Che Liu;Jianan Zhang;Shuo Liu;Tiejun Cui
{"title":"Electromagnetic Metamaterials: From Classical to Quantum","authors":"Jianwei You;Qian Ma;Lei Zhang;Che Liu;Jianan Zhang;Shuo Liu;Tiejun Cui","doi":"10.23919/emsci.2022.0005","DOIUrl":"https://doi.org/10.23919/emsci.2022.0005","url":null,"abstract":"Electromagnetic (EM) metamaterials are artificially engineered materials with extraordinary EM properties beyond the limit of existing natural materials; thus, they have been widely used to manipulate the amplitude, phase, polarization, frequency, wave vector, waveform, and other degrees of freedom of EM waves in many practical applications. In this review, we will summarize recent advances in this flourishing field of EM metamaterials, first from the perspectives of the classical regime and then the quantum regime. More specifically, in the classical regime, traditional EM metamaterials are based on effective medium theory, and they have limitations of fixed functionalities and an inability to control EM waves in real time. To overcome these restrictions, information metamaterials, including digital coding and field-programmable metamaterials, have recently been proposed to enable real-time manipulation of EM waves based on the theory of information science. By taking advantage of information metamaterials and artificial intelligence, another crucial milestone of intelligent metamaterials has been achieved in the development of classical metamaterials. After overviewing EM metamaterials in the classical regime, we discuss cutting-edge studies of EM metamaterials in the quantum regime, namely, topological metamaterials and quantum metamaterials. These nonclassical metamaterials show excellent ability to flexibly manipulate the quantum states, and they extend the classical information metamaterials into the field of quantum information science. At the end of this review, we will give some conclusions and perspectives on this fast-evolving field.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 1","pages":"1-33"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10105876/10105855.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50330154","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":"Multimode Resonator Technique in Antennas: A Review","authors":"Lei Zhu;Nengwu Liu","doi":"10.23919/emsci.2022.0004","DOIUrl":"https://doi.org/10.23919/emsci.2022.0004","url":null,"abstract":"During the past several decades, the multimode resonator (MMR) technique has been extensively investigated and widely used, with successful exploration of a variety of high-performance patch antennas, slot antennas, dielectric resonant antennas, dipole antennas, and so on. In this review paper, we summarize the research milestones for these MMR antennas worldwide as one of the most contributive research teams in this field. First, the basic working principles of the MMR technique are clearly illustrated and studied, including mode excitation, mode suppression, impedance performance improvement, and radiation performance improvement. Next, the research topics regarding impedance performance enhancement, i.e., wide-bandwidth operation, multibandwidth operation, and mutual coupling reduction, based on the MMR method are intensively described. After that, the relevant works on radiation performance enhancement, i.e., high-gain, wide-beamwidth, multibeam, multipolarization, low-cross-polarization, filtering-response, and leaky-wave antennas, based on the MMR method are extensively illustrated. By using this technique, several ideas about operating frequency reallocation, electric-field null control, radiation pattern reshaping, and efficiency null generation of the antennas are proposed and demonstrated by our team for the first time. In addition, the application of the MMR technique for wireless communication systems is introduced and presented, such as implant communication, wireless power transfer, and multiple-input multiple-output communication. With these arrangements, exploration and reporting of more interesting and useful MMR design methods can be anticipated in the future.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10105876/10105879.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50330158","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":"Differential Antennas: Fundamentals and Applications","authors":"Yueping Zhang","doi":"10.23919/emsci.2022.0002","DOIUrl":"https://doi.org/10.23919/emsci.2022.0002","url":null,"abstract":"Driven by the great demand for highly integrated wireless system-on-chip and system-in-package devices, there has recently been increasing interest in the research and development of differential antennas. Many studies on the design, analysis, and measurement of differential antennas have been published. This paper presents an overview of the fundamentals and applications of differential antennas. First, it compares differential to balanced and single-ended to unbalanced antennas and explains why the new terms (differential and single-ended antennas) should be adopted instead of the old terms (balanced and unbalanced antennas). Second, it addresses the quantitative relationship between a differential antenna and its single-ended counterpart, which is important and useful because the properties of either the differential or single-ended antenna can be determined from the other with a known solution. Third, it describes how differential antennas can be measured, with a special emphasis on the balun method. Fourth, it classifies differential antennas into wire, slot, microstrip, printed, and dielectric resonator antennas to better present their suitability and functionality. Fifth, it provides application examples of differential antennas from simple discrete wire to sophisticated microstrip designs. Finally, it is argued that the old paradigms of lower gains and bulkier sizes of differential antennas as compared to single-ended antennas do not always hold true; for instance, differential microstrip patch antennas can possess comparable or even smaller sizes and higher gain values than single-ended microstrip patch antennas.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 1","pages":"1-17"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10105876/10105878.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50330157","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":"Pulse Generation and Compression Techniques for Microwave Electronics and Ultrafast Systems","authors":"Ke Wu;MuhibUr Rahman","doi":"10.23919/emsci.2022.0013","DOIUrl":"https://doi.org/10.23919/emsci.2022.0013","url":null,"abstract":"Ultrabroadband systems and ultrafast electronics require the generation, transmission, and processing of high-quality ultrashort pulses ranging from nanoseconds (ns) to picoseconds (ps), which include well-established and emerging applications of time-domain reflectometry, arbitrary waveform generation, sampling oscilloscopes, frequency synthesis, through-wall radar imaging, indoor communication, radar surveillance, and medical radar detection. Impulse radar advancements in industrial, scientific, and medical (ISM) domains are, for example, driven by ns-scale-defined ultrawideband (UWB) technologies. Nevertheless, the generation of ultrashort ps-scale pulses is highly desired to achieve unprecedented performances in all these applications and future systems. However, due to the variety and applicability of different pulse generation and compression techniques, the selection of optimum or appropriate pulse generators and compressors is difficult for practitioners and users. To this end, this article aims to provide a comprehensive overview of ultrashort ns and ps pulse generation and compression techniques. The proposed and developed pulse generators available in the literature and on the market, which are characterized by their corresponding pros and cons, are also explored. The theoretical analysis of pulse generation using a nonlinear transmission line (NLTL) presented in the literature is briefly explained as well. Additionally, a holistic overview of these pulse generators from the perspective of applications is given to describe their utilization in practical systems. All of these techniques are well summarized and compared in terms of fundamental pulse parameters, and research gaps in specified areas are highlighted. A thorough discussion of previous research work on various topologies and techniques is presented, and potential future directions for technical advancement are examined.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 1","pages":"1-24"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10105876/10105880.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50330320","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":"Transmitarray and Reflectarray Antennas Based on a Magnetoelectric Dipole Antenna","authors":"Kwai-Man Luk;Bingjie Xiang","doi":"10.23919/emsci.2022.0009","DOIUrl":"https://doi.org/10.23919/emsci.2022.0009","url":null,"abstract":"This paper presents a review of transmitarray (TA) and reflectarray (RA) antennas based on the magnetoelectric (ME) dipole antenna structure. First, the basic operating principles of ME dipole, TA and RA antennas are introduced. Next, ME-dipole-based TA and RA designs are discussed, with four antenna designs presented in detail, including two fixed-beam TA designs with high aperture efficiencies and two reconfigurable designs with a beam-scanning capability. The techniques involved in these designs are also analyzed to provide insight into the ME-dipole-based TA and RA designs. The simulated and measured results of the reported prototypes show that the introduction of the ME dipole antenna significantly broadens the bandwidths of the TA and RA antennas not only in the fixed-beam designs but also in the reconfigurable designs. The ME-dipole-based TA and RA designs reported in this paper are compared to highlight their benefits and limitations. Future possible research directions and challenges are also discussed.","PeriodicalId":100402,"journal":{"name":"Electromagnetic Science","volume":"1 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/10105875/10105876/10105881.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50330153","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}
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