THE PROBLEM COULD BE LESS SERIOUS

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Department of Electrical Engineering và Computer Science, South Dakota Mines, Rapid City, SD 57701, USA
Department of Electrical và Computer Engineering, North Dakota State University, Fargo, ND 58105, USA
Received: 16 August 2022/Revised: 27 September 2022/Accepted: 4 October 2022/Published: 17 October 2022
(This article belongs lớn the Special Issue Advances in Antennas, RFID và Metamaterials for 5G và Internet of Things (IoT) Application Areas)

A step-by-step explanation of Transformation electromagnetic/optics (TE/TO) technique, where an original space, G is transformed into a new space, G′, with new material parameters ε, μ <32>.

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A linear coordinate transformation of a beam shifter & its application (a) appropriate coordinate transformation for up-shifting. (b) a phối of beam shifters for both up-shifting and down-shifting.

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Metamaterial based cylindrical beam-steerer using lớn enclosing a single dipole element <37>.

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Full wave COMSOL simulations demonstrating electromagnetic cloaking of a concealed object. (a) an unperturbed TE wave in the free space, (b) a perfect electric conductor (PEC) is introduced, and significant scattering properties are observed, (c) a metamaterial shell is introduced around the cloaked object, và the wave bend around the object thus mitigates the scattering significantly.

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Total electric field distributions for three different array configurations for a scan angle of θs = 22.50 for <53> (a) reference/original dipole antenna linear array, (b) “pinwheel” antenna array without any material compensation, (c) material−embedded “pinwheel” shaped antenna linear array, & (d) difference between the electric fields in (a,c).

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Inductive coupling for WPT system.

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Magnetic resonant coupling for WPT system.

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Strongly coupled magnetic resonance for WPT system.

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Three topologies: (a) series (b) voltage doubler và (c) Greinacher.

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Type of DoA beamforming và subspace algorithms.

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MUSIC ULA with phase shift between adjacent elements.

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ESPRIT Sub-Arrays, M element array with two (M-1) sub-arrays.

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FBSS, 6 element array with 3 sub-arrays of kích cỡ p = 4.

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General structure of WBAN.

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Tires of communication in WBANS.

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Energy Harvesting System.

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The harvesting process for a sensor node in wireless toàn thân area networks. Energy from nonelectrical sources is scavenged and converted to electric potential using appropriate energy harvesters for specific source.

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An RFID system.

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PIN diode mã sản phẩm and its Equivalent circuits for ON and OFF states.

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The structure of the proposed antenna.

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Evolution of thiết bị di động broadband is ensured by adopting a unified và more capable radio interface (RI). For ubiquitous connectivity among a wide variety of wireless applications, the RI enables the adoption of an adaptive bandwidth with high spectrum flexibility. Lớn this end, the modern-day communication system needs to lớn cater lớn extremely high bandwidth, starting from below 1 GHz to lớn 100 GHz, based on different deployments. This instigates the creation of a platform called the mạng internet of Everything (IoE), which is based on the concept of all-round connectivity involving humans to different objects or things via sensors. In simple words, IoE is the intelligent connection of people, processes, data, & things. Khổng lồ enable seamless connectivity, IoE resorts to lớn low-cost, compact, and flexible broadband antennas, RFID-based sensors, wearable electromagnetic (EM) structures, circuits, wireless body area networks (WBAN), and the integration of these complex elements and systems. IoE needs khổng lồ ensure broader information dissemination via simultaneous transmission of data to lớn multiple users through separate beams & to that end, it takes advantage of metamaterials. The precise geometry và arrangement of metamaterials enable smart properties capable of manipulating EM waves and essentially enable the metamaterial devices khổng lồ be controlled independently to achieve desirable EM characteristics, such as the direction of propagation and reflection. This reviews paper presents a comprehensive study on next-generation EM devices & techniques, such as antennas and circuits for wearable và sub 6 GHz 5G applications, WBAN, wireless nguồn transfer (WPT), the direction of arrival (DoA) of propagating waves, RFID based sensors for biomedical and healthcare applications, new techniques of metamaterials as well as transformation optics (TO) và its applications in designing complex truyền thông and arbitrary geometry conformal antennas và optical devices that will enable future IoE applications.
In this modernized era, embedded devices with different types of machinery, sensors, and other utilities connected to the mạng internet have revolutionized và changed people’s convenience in living standards. The internet of Things (IoT) utilizes the mạng internet or wireless communication to combine all objects, sensors, or machinery in a physical system. The internet of Everything (IoE) is a concept that emphasizes the mạng internet of Things (IoT) by focusing on a more complicated system for the machine-to-machine connection that also includes people-to-people as well as people-to-processes connections. It is a super-ordinate of IoT, a domain name where many smart objects connect over public or private networks that use specific protocols lớn produce real-time data. This IoE is based on the combination of three pillars: intelligent objects, information-centric networks, & real-time insights data from sensors <1>. For information-centering networks of IoE, the bandwidth requirement is a crucial aspect <1>.
In recent years, wireless communications và IoE have made significant growth. The next-generation wireless công nghệ is the combination of environmental sensing, data processing, and highly efficient electromagnetic devices <2>. Furthermore, it has been observed that there is a noticeable amount of increasing wireless devices in developed cities <3>. One of the significant challenges in wireless communications is high bandwidth devices transmitting simultaneously with short packets. In contrast, the standard requirement is khổng lồ design less complex, energy-efficient communication schemes. Another vital challenge appears to lớn develop effective methods for detecting a small number of active users among a significant number of possible user devices with erratic transmission patterns <4>. These new challenges require fundamental fresh thinking technologies, which will also favor the newest applications of IoE.
Future wireless communication technologies are anticipated lớn create a path for the mạng internet of Everything (IoE) concept, which envisions a network of interconnected devices without the help of any media. Such significant technologies which focus on this increasing research interest và also are involved and implemented in real life have been reviewed in this article. Here, a descriptive overview has been presented on the direction of arrival, theory of transformation electromagnetic or optic for developing meta-material devices, wireless power transfer, sub-6 GHz for implementing 5G communication, wireless body area network, etc. These technologies can be integrated with IoE to lớn gain more bandwidths và data rates for simultaneous wireless information & power transfer. This article will focus on these prominent wireless connectivity technologies that can be integrated into the big IoE picture.
Meta-materials are manufactured structures made up of sub-wavelength elements with unique and beneficial features not found in nature <5>. Recent studies have demonstrated that meta-materials can improve a variety of antenna attributes, including bandwidth, gain, and kích cỡ <6>. Meta-material has also shown outstanding performance in sub-wavelength focusing, EM metal, cloaking, 5G communication, mạng internet of Everything (IoE), internet of things (IoT), etc. <7,8>. Furthermore, in <2>, it has been discussed how programmable meta-materials và meta-surfaces can achieve huge advantages for simultaneous wireless information transfer, wireless nguồn transfer, wireless energy harvesting, & 5G communication. Furthermore, meta-materials and meta-surfaces have inspired many new electromagnetic (EM) theory concepts and design techniques for EM devices và systems. In Section 2, a detailed analysis has been presented on one of the EM theories: transformation electromagnetic or transformation optics (TE or TO) for the development of meta-material-inspired electromagnetic devices. Furthermore, a novel approach has been discussed on how lớn design beam shifters by implementing the same TE/TO technique to lớn get the desired direction.
Wireless power Transfer (WPT); also known as wireless power transmission, wireless energy transmission, or electromagnetic power transfer), transfers electrical power or energy from a nguồn source to one or more loads by generating a time-oscillating electromagnetic field without any help of a physical liên kết or wire <9>. Recently, this technology has gained enormous attention due to lớn its special applications in our daily life to lớn industrial implementation; such as portable electronic devices, biomedical implants, wireless sensors, radio-frequency identification (RFID), unmanned aerial vehicles, remote charging, & powering of electric vehicles <10>. Section 3 presents an overview of the near-field và far-field WPT techniques. The radio-based WPT has a broad impact on the operation of IoE devices in the home, industries, as well as commercial thiết lập <11>. For the radio-based WPT, radio frequency signals carry the energy simultaneously, which allows charging a number of heterogeneous devices effectively, which will help a lot in the case of the IoE industry <12>. Recently using a relatively small antenna array, this WPT công nghệ has shown incredible performance in systems operating in the microwave band (sub-6 GHz) <11>. In the field of small and multiband antennas for IoT devices, antenna booster technology <13> relies on electrically small elements that are able lớn excite radiating currents in the ground plane of the IoT device. The proposed matching network <13> makes it easy and fast lớn operate from single to lớn multiband operation with passive or tunable components. In general, in a wireless toàn thân area network, the nguồn source or the batteries for the sensors need lớn be recharged, where WPT, with the help of DOA, can be implemented to charge the sensors placed in any movable object wirelessly.
The direction of Arrival (DoA) estimation has widely spread applications in wireless communication. To get better & smart performance, this technique can be integrated with smart antennas, 5G, wireless nguồn transfer, radar systems, radio astronomy, wireless sensor network, etc. As with the help of DOA the position can also be determined of the object where we need khổng lồ transfer the information or power simultaneously. Therefore, a lot of research work focuses on discovering the algorithm to lớn detect the direction of the incident signal. Section 4 discussed different DoA subspace algorithms such as MVDR, conventional MUSIC và ESPRIT (LS-ESPRIT), improved MUSIC, SVD-ESPRIT, và modified ESPRIT (T-ESPRIT & MSVD-ESPRIT). The ESPRIT algorithm surpasses MUSIC by providing a less computation-intensive technique. In contrast, the improved subspace algorithm based on the SVD method và reconstruction of the matrices can successfully estimate the coherent signals DoA. However, it has been supported further by using the Toeplitz matrix reconstruction nature or forward-backward exceptional smoothing (FBSS) lớn provide enhanced performance and better resolution under low SNR.
The modern healthcare system has reached such a point where medical devices can generate data & send it to lớn be recorded, remotely monitored, và controlled. It is expected that the doctors or physicians và the patient’s relatives will have remote access lớn these data. Therefore, Wireless toàn thân Area Network (WBAN) can be a part of the IoE concept by connecting with the internet via Wi-Fi, ZigBee, Bluetooth, etc. Wireless toàn thân area networks (WBANs) are an emerging wireless công nghệ expected lớn revolutionize the healthcare system by proceeding with real-time monitoring and data analysis from the sensor data <14>. Section 5 aims to report an overview of the concept of wireless body area network (WBAN) with different network architectures, applications, characteristics, hardware thiết kế issues, types of devices, và supporting radio technologies, protocols, standards, & existing challenges. With the widespread use of wireless sensors, energy efficiency has become a concern of today’s research. Wireless sensors usually get power nguồn from batteries as a power nguồn source. However, battery replacement can be unmanageable in some applications & may require considerable time, affecting the monitored process. However, harvesting energy from natural sources for wireless sensors is also possible. Furthermore, a comprehensive discussion regarding different energy harvesting methods has been discussed with alternative energy sources for wireless body area networks khổng lồ generate self-sustainable electrical power. WBANs are thought lớn be impossible khổng lồ implement without 5G connections <15>. In the future, it is expected that more sophisticated applications will be performed with the help of high data rates under the sixth generation (6G) of wireless networks <16>.
IoE/IoT has a significant impact on biomedical & healthcare applications such as monitoring patients remotely, hospital và medical waste management, body scanning to detect cancer, smartwatches to lớn analyze depression, remotely nurse assistance, etc. <17>. Integrated wireless technologies with IoE pave the way to lớn make this application a reality. To facilitate the IoE network, one of the rising pervasive technologies is a radio-frequency identification (RFID). It is a short-range wireless công nghệ used in a wireless sensor network that enables the internet to reach out khổng lồ the physical objects of real life <18>. Furthermore, RFID interconnects with wireless nguồn transfer and toàn thân area networks. Many research works have been performed to deliver nguồn wirelessly khổng lồ RFID devices <19>. Furthermore, the wireless body toàn thân area network system can be integrated with the RFID giải pháp công nghệ to achieve higher efficiency <20>. Section 6 presents a brief discussion on how RFID has played an influential role in modern healthcare applications. The block architecture of RFID systems and the characteristic of active và ultrahigh-frequency (UHF) passive RFID tags have been discussed here. Moreover, a number of research works with the application in biomedical science that happened in the past decades have been reviewed thoroughly.

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The development of millimeter-wave 5G wireless technology-enabled IoT/IoE devices will revolutionize the electronics & telecommunications fields <21>. This innovation is one of the most significant achievements in wireless communication và IoE. The combination of 5G và IoE will allow higher data rates, more customer capacity, & more coverage with an increasing number of connections. It will be the path of reality for smart devices <22>. Intelligent devices based on the IoE are extending their tư vấn for mạng internet connectivity. These devices have been combined with cutting-edge công nghệ to manage and communicate efficiently utilizing 5G wireless technology. The 5G wireless communication provides the most outstanding advantage over previous 4G or 3G technology by providing real-time communication of IoT devices as 5G offer greater bandwidth in millimeter bands <23>. With the help of this 5G IoE, many researchers are currently focused on constant wireless powered communication (WPC) <24>, which can be an excellent initiative for the green batteryless network for low profile wireless sensor networks <25>. For the implementation of 5G, two frequency ranges need khổng lồ be focused on: sub-6 GHz (less than 6 GHz) and mmWave (above 24 GHz). Section 7 focuses on the 5G implementation (sub-6 GHz) where single & multiple antenna element systems have been briefly reviewed.
The recently introduced transformation electromagnetics/optics (TE/TO) technique <26,27> has revolutionized the developments of meta-materials & devices based on these meta-materials. The TE/TO technique provides extraordinary flexibility of designing electromagnetic devices using an appropriate coordinate transformation method. This also provides an exceptional avenue for registering unique & novel wave-material interactions. The TE/TO kiến thiết approach is based on the key assumption of the form-invariance of Maxwell’s equations under coordinate transformations <28,29>. Another observation is the interpretation of the material parameters (ε, μ) in the transformed coordinate system as a set of material parameters in the original coordinate system <30>. Now, consider the time-domain Maxwell’s curl equations: