Magnetic nanoparticles (MNPs) have been widely investigated as effective drug carriers for targeted tumor therapy. However, the successful application of this technology in the human body requires reliable imaging support. Magnetoacoustic Concentration Tomography of Magnetic Nanoparticles with Magnetic Induction (MACT-MI) is an electromagnetic-ultrasonic coupling imaging technique that holds great promise in improving imaging resolution and providing unique advantages for tumor monitoring and treatment. To evaluate the imaging feasibility of MACT-MI technology for targeted therapy of breast tumors, this study establishes a realistic breast model and takes into account the distribution of magnetic particles within the actual breast tissue environment. A concentration gradient model is introduced, and the finite element method is employed to solve the electromagnetic and sound fields. In addressing the research objective, the forward problem is investigated by analyzing the magnetic force and sound pressure distribution for various tumor sizes and locations, different breast tissues, and both benign and malignant tumors. The results obtained indicate that the magnetoacoustic signal emitted by magnetic particles facilitates accurate mapping of the size and location information of magnetic particles enveloping breast tumors, as well as distinguishing between benign and malignant tumors.

Wireless technology, a longstanding focus for researchers, has evolved into an exciting telecommunications topic over several decades. The most recent iteration, Fifth Generation (5G), has been introduced at high frequencies, commonly called millimeter waves. An integral component supporting wireless communication is the antenna. This report details the design of a microstrip antenna operating at a frequency of 26 GHz. The antenna is configured as a rectangular patch microstrip, utilizing coupled slot feeding, organized as an array, and implementing a ring as the gain enhancement technique. The designed antenna undergoes observation for both single-element and 1x2 arrays, both with and without rings. A thorough analysis encompasses gain, bandwidth, return loss, and radiation pattern. The antenna design, developed at a frequency of 26 GHz, demonstrates a substantial gain increase of up to 10 dB and 14 dB in the single-element and 1×2 array configurations achieved by adding a ring. The designed antenna surpasses the previous works' gain of about 3 dB more.

In this research work, a flexible polymer-based compact wearable antenna has been designed, fabricated, and analysed for Wireless Body Area Network (WBAN) IoT enabled applications. The antenna is fabricated on a Polyethylene Terephthalate (PET) with λ_L as the lowest operating free-space wavelength resonating for sub-6-GHz band at 2.4 GHz, 3.3 GHz, 4.1 GHz and 5.8 GHz. Periodic Frequency Selective Surface (FSS) reflector is used which reduces Electromagnetic Interference (EMI) antenna and enhances the gain of the antenna. The simulation results prove that this flexible wearable antenna radiates an increased gain of approximately 10 dB and returns loss of -36 dB at lowest frequency with FSS as a reflector. The simulation results are validated by experimental results which offer a good agreement. An average SAR value of l.5 watts/gm is measured within the specific safety limit which makes it feasible for practical implementation. This antenna provides better isolation against on-body losses and reduces SAR value with improved radiation efficiency for WBAN IoT enabled applications.

Microwave-assisted extraction (MAE) is an effective method for extracting tea polyphenols. However, research on MAE mainly focuses on experimental methods, which not only leads to a large amount of experimental work but also generates a lot of material waste. In addition, due to the lack of mechanism research, it is difficult to find a more effective method. In this study, based on electromagnetic field theory, the heat and mass transfer model of tea polyphenol extraction is established based on measuring the dielectric properties of the extract. The distribution of temperature, diffusion coefficient, and flow rate of microwave-assisted extraction of tea polyphenols are all analyzed in detail. The results show that the temperature distribution in the extraction system is uneven. The middle temperature of the extraction solution is high and the edge is low. Moreover, with the increase of microwave power and extraction temperature, the diffusion coefficient is gradually increased, and the flow rate increases, which is more conducive to the extraction process as time goes by. This study provides a theoretical basis for the microwave-assisted extraction of tea polyphenols, reducing experimental workload and material waste.

A new circularly polarized (CP) array using the filtering phase shifting theory is designed. First, it is displayed that a phase designable filter can be obtained by controlling the position of the transmission zero (TZ) of the doublet topology. Next, by mapping the topology into a stub-loaded resonator (SLR) and using the patch as the last resonating mode, a phase designable 3rd-order filtering antenna element is designed. Then, two filtering antenna elements with 90° phase difference are obtained. Finally, by using the slot-coupled feed structure, four elements with phases of 0°, 90°, 180°, 270° are rotated sequentially to form a circularly polarized array. The measured results show that the impedance bandwidth is 8.1% (5.07-5.5 GHz); the axial ratio (AR) bandwidth is 6.7% (5.05-5.4 GHz); the maximum CP realized gain is 10.5 dBic; and the good filtering function is implanted.

In this paper, a microstrip filtering antenna is proposed with gain-filtering response. The antenna consists of an E-shaped radiator and a slotted U-shaped coupling structure. Three radiation nulls are obtained by the radiator, the U-shaped coupling structure and the two slots. The filtering antenna has no extra circuits, which indicates that it is easy to design. A 4-element filtering OAM antenna array is also designed to validate its applicability in OAM antennas. Measured results show excellent performance of the array, which also make it a potential candidate for 5G wireless communication devices.

This paper presents an on-chip integrated sensing circuit for real-time detection of phase currents in three-phase brushless direct current (BLDC) motors. The three-phase sinusoidal currents generated in the motor winding are detected by an innovative Sense FET technology, which can accurately measure the currents of high-side P-type power transistors and low-side N-type power transistors simultaneously. A dynamic matching elimination method is proposed for the detection current mismatch problem due to the large difference in aspect ratio. Using a 90 nm dual-polarized cmos-DMOS (BCD) process for design and verification, the detection circuit of the high and low sides can well follow the change of sine wave phase current of the three-phase motor, and the accuracy is above 96%. The best accuracy can reach 99.219%. The elimination effect of circuit current mismatch is obvious, and the error of the sense current can be reduced by 38.9%.

In this paper, the power handling of a slot loop frequency selective surface based on approximate analytical method is proposed. The physical nature of the slot array periodic moment method is derived in detail. It is found that the left and right sides of periodic scatter matrix respectively represent the total tangential magnetic field acting on the left and right magnetic dipole arrays and moving in the direction of the reference array. According to the principle of equivalence, a slot array can be modeled by an array of magnetic currents on each side of the perfect electronic conductor. As a result, the total tangential magnetic field is zero in the sense of physical concept. Furthermore, a simple sinusoidal function is then used to approximate the magnetic current distribution along the slot loop which is similar to that of dipole antenna. By studying the corresponding zero points and extreme point of the magnetic current for the slot loop frequency selective surface element, the transmission coefficients and maximum electronic field are calculated. Examples of rectangle and triangle slot ring frequency selective surface have verified the efficiency and accuracy of the proposed method.

In this study, we investigate electromagnetically induced transparency (EIT) and Fano resonances, focusing on the propagation of electromagnetic waves in a system of parallel waveguides associated with asymmetric resonators. Our design includes five waveguides and two resonators, generating discrete modes influenced by their respective lengths. The EIT resonance is characterized by a prominent transmission peak flanked by two transmission zeros, while the Fano resonance is characterized by a pronounced transmission peak adjacent to a transmission zero. Using the transfer matrix method (TMM), we calculate transmission and reflection rates. Our results indicate that the EIT resonance appears when the resonator lengths show slight differences, whereas the Fano resonance appears when the resonator lengths are identical. Both resonances are sensitive to resonator lengths and permittivity indices. Consequently, the geometrical parameters of the system must be carefully selected according to the application in question, whether waveguiding or multi-channel electromagnetic filtering.

A microstrip patch antenna of red cross bag shape is designed, simulated, and fabricated. The antenna is designed to work at 5.8 GHz for on-body applications. Small size, low specific absorption rate, and high front to back ratio with a low-profile design are achieved. The measured frequency is 5.878 GHz with 25 mm as the largest dimension used, and the matching impedance is -47.06 dB. Other parameters are recorded from the simulator, such as front-to-back ratio which is 37.37 dB and a specific absorption rate of 0.0984 W/kg in 10 gm. Finally, this work is compared with a compact dual-band antenna with paired L-shape slots, a watchstrap integrated wideband antenna, and a dual-band AMC-based MIMO. The proposed red cross bag antenna overcomes the mentioned works in terms of small size, high front-to-back ratio, and low specific absorption rate.

This article presents a novel compact ultra-wideband (UWB) planar monopole antenna printed on an FR4 substrate. The antenna consists of a pentagonal radiating element and incorporates loading metamaterial complementary split ring resonator (CSRR) on the ground plane to optimize impedance matching for UWB operation. The overall dimensions of the designed antenna are 17.75×20 mm². The proposed compact UWB antenna exhibits an operating bandwidth from 3.01 to 12.41 GHz with a -10 dB return loss, and a fractional bandwidth (FBW) of approximately 123%. Additionally, the proposed antenna exhibits a stable radiation pattern with a peak gain of 6.3 dB and a peak radiation efficiency of 98.3%. To validate the simulation results, a prototype has been fabricated and measured, which shows good coherence with the simulation results. In addition, the proposed design is compared with leading antennas for similar applications to demonstrate the suitability of its concept. Moreover, an equivalent circuit model of the CSRR metamaterial cell is developed and validated using ADS software.

Turbulence is a longstanding problem in fluid mechanics for which experimentation remains unavoidable. In contrast to conventional experimental techniques that inevitably require the introduction of probes into the flow, a very convenient technique would be one in which there is no contact between the measuring sensors and the flow. The laser-based diagnostic technique reported in this work is described as an estimation of a large number of parameters defining the diffusion coefficient profile in the heated turbulent wind tunnel jet, which is required in the formula of the Karman turbulence spectrum for the jet under study. For this purpose, some required experiments in the jet are carried out. A laser beam is then sent perpendicular to the jet exhaust, and measurements of the probabilities of the position of the laser beam's impact on a photocell placed outside the jet are performed. Using the Markovian model, the same probabilities are calculated numerically. For these numerical results to agree with the experimental results, a numerical optimal-control strategy is applied. Due to the large number of unknown parameters searched, a genetic algorithm (GA) computation is performed. A good agreement observed between the GA results and those derived from the previously published cold-wire-anemometer data, combined with the use of the Dale-Gladstone law, proves the validity and accuracy of the laser-based genetic measurement technique.

In this manuscript, we propose a conformable and flexible meander dipole rectenna array for omnidirectionally harvesting ambient RF power for application in Internet of Things (IoT) water meters. The array unit consists of an antenna for RF power harvesting and a Schottky diode for converting the harvested RF power into DC power. The impedance between the antenna and diode is directly conjugated and matched using a meander structure and coupling loop. Traditional matching networks introduce additional losses, while direct conjugate matching maximizes power transmission efficiency and reduces energy losses. The elimination of the matching network simplifies the design of the rectenna, reducing the number of components and the overall size and weight. The rectenna unit is suitable for low-power ambient energy harvesting and operates at 2.45 GHz. The measured RF to DC conversion efficiency of the rectenna unit reaches 50% at 0 dBm. The rectenna array is formed by connecting eight antenna units in parallel, and units are affixed to the four surfaces of the water meter case to achieve omnidirectional RF environmental power harvesting. The output DC power of the array can be up to 1.3 mW at 100 μW/cm² received power density. An energy management circuit (BQ25504) is designed to efficiently store, distribute, and manage the harvesting of RF power for powering the IoT water meter. Measured results demonstrated that the proposed rectenna array exhibited excellent adaptability and application potential in IoT scenarios.

A novel corrugated subreflector is developed to achieve sufficient side lobe level suppression for antenna systems used in meteorological applications. The subreflector operates at 9.41 GHz, with a 60 MHz bandwidth and an efficiency of more than 70%. Its structure is rotational symmetric and is suitable for parabolic antenna applications. It can be utilized in single-polarized or polarimetric radar systems. The pattern-forming property of the subreflector is achieved with corrugations of different depths. Analytical design formulas have been deduced by solving the aperture integral. The analytical formulas provide the initial geometrical configuration and the reference illumination pattern in the objective function to which full-wave electromagnetic optimizations are performed to obtain the final corrugation depths. The subreflector has been manufactured with CNC machining. The radiation characteristics are measured, and for both polarizations, suppression of -28 dB side lobe level has been achieved with a 1.2 m diameter main reflector.

A novel stacked rectangular structure with surface-mounted short rectangle dielectric resonator antenna (SRSMSR) with an E-shaped microstrip feed through a wide aperture slot was investigated for C-band operation in wireless communication and tracking radar applications. The developed design uses copper for SMSR to improve return loss up to -46 dB, gain up to 10.7 dB, and an observed impedance bandwidth of 20.6% in the broad frequency range of 5.69 GHz-7.0 GHz. The 3 dB beam width achieved in the E-plane is 89.82˚, while that in the H-plane is 24.31˚.

The architecture of antenna is with four elements design for 5G, Wi-Max, Wi-Fi and WLAN applications. The operating range of the antenna covers the frequency band from 4.72 GHz to 5.24 GHz. The antenna has dimensions of 46 x 46 x 1.6 mm³ with four elements. The antenna is designed with a planer monopole having two matching stubs connected at the lower end. All the elements of antenna contain E and C shaped slots and two identical stubs providing capacitive effect. The Gain of the designed antennas ranges from 2.23 dB to 2.73 dB for the desired bands. The designed antenna shows suitability for 4.9 GHz WLAN band, 5 GHz and 5.15 GHz Wi-Fi and Wi-Max bands. Also it covers part of the n79 5G band.

Batteries inside an active implantable medical device (AIMD) need to be replaced every few years. However, rechargeable batteries can enhance the life of such devices to a large extent. Transcutaneous Energy Transfer System (TETS) is a promising method for recharging these batteries inside medical devices. These devices are generally made of metal casings to avoid fluid ingress and provide better mechanical strength. However, the metal cases when being present in the path of electromagnetic energy induces eddy current thus producing excessive temperature rise due to thermal loss. Thus, the selection of an interface casing material plays a significant role in the performance of the wireless recharging. In this paper, the performance of a transcutaneous energy transfer system for recharging an AIMD with different axial gaps and casing materials is reported. The effect of these variations on the output voltage, recharge current, and efficiency of operation was quantified. It has been found that, with TETS the charging current of 0.3 A to 0.5 A can be obtained to charge the implanted battery within 180 minutes. It was found that the induced voltage in the secondary coil is substantially reduced with the presence of titanium casing compared to epoxy encapsulation. Thermal studies were performed with titanium casing material of various thicknesses. The casing temperature rose to above 70˚C within the first 10 minutes for 0.5 mm thickness and within 50 minutes in the case of 0.25 mm. With epoxy encapsulation, the casing temperature rose to only 30˚C. The charging voltage of 5 V and charging current of more than 0.3 A were obtained with epoxy encapsulation. A polymeric material casing or epoxy encapsulation is the best choice in the interface region to get a high recharging current in the case of wireless recharging of implantable medical devices. With the proposed design modification, wireless energy transfer and recharging implanted batteries shall be done in a more energy-efficient manner with less thermal damage to nearby tissues.

This work concerns the study of the reliability of a magnetic levitation system. A numerical calculation method based on the introduction of a random variable on the physical property of the materials constituting the levitation system is proposed. The latter is called intrusive stochastic finite element method (ISFEM), and the randomness of physical properties is taken care of, thus modeling in uncertain medium is feasible. The electromagnetic problem is treated with 2D hypotheses for modeling in an uncertain environment. This method was developed in 1991 and used for sensitivity and reliability analysis in the mechanical field; it is extended to the study of applications in linear elasticity and in electromagnetism. The random variable is of Gaussian type. The assessment of the reliability of the levitation system is discussed. The results obtained are compared with those found by the Latin hyper cube method. The intrusive stochastic finite element model provides very conclusive results in a very short time compared to those obtained by Latin hyper cube modeling.

Taking into account the radiation characteristics of rotating permanent magnet antennas, the influence of the spatial distribution of molecular magnetic moments on the radiation characteristics was verified by performing theoretical calculations and simulations. First, the magnetic field distribution of arbitrarily shaped permanent magnets was derived based on the Biot-Savart Law, and the concentration degree of the molecular magnetic moments to the connection of the two magnetic poles and the comprehensive performance evaluation index were defined. The theoretical model to analyze the performance of permanent magnets was also established as above. Second, by controlling volume and rotational inertia to be the same, three types of permanent magnets were calculated. Finally, the optimization design process was proposed. Three preferable solutions were systematically compared and analyzed taking radially magnetized cylindrical permanent magnets as an example. Our work provides valuable insights into the design of mechanical antenna radiation sources.

In the context of the backscatter problem caused by edge diffraction on metallic curved surfaces, this study proposes a method to mitigate the scattering effect by loading different metasurface structures in four equally divided regions along the surface edge. Based on the design of the loaded metasurface on the curved surface, the interaction between the reflection field on the surface and the diffracted field is regulated by adjusting two key parameters: the reference phase (φ₀) at the edge and the phase difference (φ_d) in adjacent regions. By controlling these parameters, reduction in the monostatic radar cross-section (RCS) can be achieved when the metasurfaces are loaded onto the curved surface. By controlling the reflection phase of a sandwich-like unit structure subjected to oblique incidence of electromagnetic waves, a metasurface that meets the requirements has been designed. Through a comparison and analysis of the near field and monostatic radar cross-section before and after loading the metasurface, the effectiveness of this design method is confirmed. This method is of great significance to control the electromagnetic scattering caused by edge diffraction.