The integration of directed energy weapons (DEWs) into modern military platforms is of considerable interest to those examining the impact of emerging technology on the future fighting force. Hence the performance prediction of DEWs is of importance. The purpose of this study is to develop a simple framework where the minimum number of DEWs deployed in an operational setting can be determined, to achieve a desired level of performance.

The proposed work focuses on the mathematical interpretation of Electromagnetic Shielding Effectiveness (ESE) of age-dependent human Head Models (HMs) of seven tissues (Skin, Fat, Bone, Dura, Cerebrospinal fluid (CSF), Gray matter, and White Matter) with the impact of the mobile phone holding position on the RF radiation absorption by the human head. The ESE is first simulated and estimated using the Transmission Line Method approach: a. for only layered human Head Models (HMs) in the absence of mobile position with variation in Oblique Angle of Incidence (OAI) in Transverse Electric Polarization (TEP) and Transverse Magnetic Polarization (TMP), b. in the presence of mobile phone position and Polarization. c. by incorporating the Transparent Conductive Metal Mesh Polyethylene terephthalate (PET) film (Copper grid PET Film) as a shielding material in the presence and absence of Polarization and mobile phone holding positions. The Copper grid PET Film is composed of optical PET film laminated with Copper (Cu) and Nickel (Ni) Transparent Conductive Mesh Coatings (TCMCs) to form a transparent laminated mesh. The radiation absorption characteristic, Specific Absorption Rate (SAR), is evaluated numerically at four Sub-6 GHz frequencies from the obtained ESE data to draw collation at the least SAR absorbed by the age-dependent HMs, considering the water contents of tissues. Out of adult and child HMs, the child HM absorbed the higher RF SAR. However, with the transparent PET/Cu/Ni Laminated Mesh (LM), at 5.47 GHz, the SAR by the brain's white matter in child HM is highest in TEP with no shield considered is 10 W/kg. With transparent LM, the SAR obtained is 2.8e-12 W/kg in TEP in no mobile phone tilt condition at 89˚ OAI. With the user mobile tilt at 15˚ and 30˚, the SAR absorbed by the brain WM is 2.62e-12 W/kg and 2.1e-12 W/kg, respectively at 89˚. Hence, the SAR absorption is the least in any direction (azimuth or elevation) when the mobile phone is tilted to 30˚ in TE Polarization using the transparent PET/Cu/Ni laminated mesh. Therefore, the usage of transparent PET/Cu/Ni laminated mesh in TE Polarization saw the least SAR absorbed, whether the mobile phone is tilted either towards or away from the head when the mobile phone is moved to 15˚ or 30˚ tilted position.

A compact Sub-6 GHz Multiple-input Multiple-output (MIMO) antenna based on a complementary split-ring resonator (CSRR) and electromagnetic bandgap (EBG) is proposed in this paper. The antenna has an interesting structure and a compact size of 38×38 mm². Four identical antenna elements are deposited orthogonally to each other, using polarization diversity and adding decoupling structures, so that good isolation and miniaturized size can be obtained. The isolation is less than -17.5 dB in the operating bandwidth of 3.28-3.62 GHz and -19.5 dB in 4.78-5.04 GHz. The simulation results are consistent with the measured ones, indicating that the antenna is suitable for Sub-6 GHz communication equipments.

Variations of modified E-shape microstrip antennas are proposed which realize wideband and circularly polarized responses inside the same impedance bandwidth but in separate frequency regions. The offset pair of slots in E-shape patch tunes the spacing in between TM₀₂, TM₁₀ and TM₁₁ mode frequencies, and for the design in 900 MHz frequency band, it yields the total impedance bandwidth of 34.15%, in which circularly polarized bandwidth of 4.75% is present towards the higher frequency region. In comparison with the wideband E-shape or its circularly polarized variation, proposed configurations yield larger total impedance and same axial ratio bandwidth, but without overlapping bands for the wideband and circularly polarized regions. A compact half E-shape microstrip antenna is proposed, which yields total impedance bandwidth of 38.8%, with a circularly polarized bandwidth of 5.3%, present towards the higher frequency region. Further, the wideband E-shape variations are presented on a thinner substrate by using a bow-tie shape ground plane profile. Against the conventional ground plane design, it offers more than 12% increase in the bandwidth for 0.03λ_g reduction in the substrate thickness. Thus, as against the reported E-shape variations, proposed study presents a new design feature of traditional E-shape patch that provides separate regions for the wideband and circularly polarized responses, occupying the same impedance bandwidth.

A compact triple band monopole antenna with a simple modified C-shape structure for vehicle-to-everything (V2X) application is presented. The proposed multiband vehicle antenna with three C-shaped round stubs structure satisfies the worldwide interoperability for microwave access (WiMAX), wireless local area network (WLAN), and wireless access in vehicular environment (WAVE) bands. The three resonant frequencies are implemented with three C-shaped round stubs, and they are simply controlled by adjusting the round stub length without influence each other. The presented antenna demonstrated good impedance bandwidth and nearly omnidirectional radiation patterns over the whole operating bands. The field communication tests by connecting the vehicular communication module were also performed and verified in the view of automotive vehicle antenna application.

Despite recent advances, fast and reliable Human Activity Recognition in confined space is still an open problem related to many real-world applications, especially in health and biomedical monitoring. With the ubiquitous presence of Wi-Fi networks, the activity recognition and classification problems can be solved by leveraging some characteristics of the Channel State Information of the 802.11 standard. Given the well-documented advantages of Deep Learning algorithms in solving complex pattern recognition problems, many solutions in the Human Activity Recognition domain are taking advantage of those models. To improve the time and precision of activity classification of time-series data stemming from Channel State Information, we propose herein a fast deep neural model encompassing concepts not only from state-of-the-art recurrent neural networks, but also using convolutional operators with added randomization. Results from real data in an experimental environment show promising results.

This article presents a dipole antenna using an I-shapes adding technique on both sides of the antenna's body. To increase the using frequency range to be wider, with horn waveguide for gain enhancement and harvest energy by matching circuit. Which is compatible with the voltage multiplier circuit at RF frequency (510-790 MHz) in a TV digital system. When taken to measure the effect of the antenna, it was found that the antenna operates at a frequency range of 60.24% (450-838 MHz), a 67.79% increase from the base dipole antenna, which has the gain enhancement of 10.23 dB from adding the horn waveguide 60.99%. By has a pattern of energy radiating in a specific direction, and when the antenna is used with an energy harvesting circuit to get energy or power from the front direction of the TV digital antenna at a distance of 10 km, capable of harvesting energy up to 7.33 uW.

Graphene has become one of the most essential materials in recent years due to its numerous advantages and benefits. Because of its features, graphene is becoming more widespread in a variety of applications, particularly in electrical devices. In this research, graphene thick film paste (GTP) has been used to fabricate a microstrip bandpass filter (BPF). To obtain graphene nanoparticle powder, graphene oxide (GO) was synthesized from nanoparticle graphite using the Improved Hummers Method (IHM). The graphene oxide (GO) was chemically reduced to reduced graphene oxide or graphene (rGO) using ascorbic acid as the reducing agent. The structural and morphological properties of three nanoparticle powders, G, GO, and rGO, were investigated. An X-ray Diffractometer (XRD) (Rigaku Miniflex) with a diffraction angle of 10˚ to 60˚ was used to differentiate and determine the structure of crystalline materials. Thermal stability of the samples was identified using thermogravimetric analysis (TGA). The synthesized rGO has been used to fabricate BPF circuit. The obtained nanoparticle rGO was mixed with an organic carrier composed of linseed oil, m-xylene, and α-terpineol to form GTP. The GTP was screen printed on RT duroid 5880 substrates to form BPF circuit. The BPF circuit that was created was tested for paste-to-substrate adhesion. Then, the fabricated BPF circuit was tested using vector network analyzer (VNA) and compared with conventional BPF to obtaine scattering parameter results which include return loss, insertion loss, and bandwidth. The graphene BPF circuit demonstrated a good performance with return loss and insertion loss at -27.481 dB and -0.725 dB, respectively, and a bandwidth of 1.5916 GHz while conventional return loss was -26.750 dB and insertion loss value the same as graphene which is -0.725 dB and bandwidth 0.7077 GHz. From the result graphene BPF showed better result than conventional BPF.

In this paper, the transport characteristics of gold/silver mixed chain nanostructures with different proportions of infinite length in the range of 270-810 nm are studied, and the corresponding band gap characteristics and other transport characteristics are analyzed. We introduced an analytical model to determine the complex dielectric constant of an arbitrary composition Au-Ag alloy, and combined this with the experimental data to study the propagation characteristics of the infinite-length gold-silver mixed-chain nanostructures with various compositions. As the gold content exceeds Au:Ag(1:2), the coupling coefficient between the forward and reverse waves becomes smaller, and the reverse wave cannot provide enough energy to transfer to the forward wave. The scattering ability of the scattering unit weakens, the frequency range of the propagation state widens, and it exhibits good propagation characteristics. By gradually increasing the proportion of metal in the alloy, we can explore the variation of the propagation characteristics of the alloy. At present, the change of metal propagation characteristics has not been studied from this point at home and abroad, so we found for the first time that frequency modulation can be realized through this method (regulating the attenuation or cutoff frequency range, namely the band gap range). We also studied a cylindrical finite array chain composed of 40 nanorods under five types of experimental data and discussed the wave guiding ability of the finite array chain under the excitation of a plane wave of a specific wavelength.

Bond wires aging is one of the most common failure modes of insulated gate bipolar transistor (IGBT) module. Real-time monitoring of bond wires status is an important guarantee for the stable operation of power electronics system. In this paper, a method of monitoring the aging state of bond wires in IGBT module based on the spectrum characteristics of electromagnetic radiation (EMR) signature is proposed. Firstly, the turn-off process of IGBT module is analyzed, and the behavior model of IGBT module in the stage of rapid current change is established, which shows that EMR interference in buck converter mainly occurs during the turn-off process of IGBT module. Secondly, the relationship between the aging degree of bond wires and differential mode (DM) interference signal is deduced. Thirdly, the IGBT module is equivalent to a magnetic dipole, which proves that the change of DM interference signal will cause the change of EMR signal, thus demonstrating the feasibility of using EMR signal to monitor bond wires aging. Finally, a buck converter composed of IGBT module is used as the equipment to be tested. The EMR signal is extracted by the near-field probe, and the EMR signal spectrum is used to monitor the aging degree of the bond wires. The experimental results show that with the deepening of the aging degree of bond wires, the spectrum amplitude of EMR signal increases.

This work studies the correlation between 14-elements of a sub-6 GHz MIMO antenna for mobile terminal, operating in the 3.10 to 3.85 GHz frequency band. Envelope correlation coefficient (ECC) was used to assess the relationship between MIMO antenna elements. A total of 91 ECC values were considered at every frequency point for the 14-element antenna, which was performed under two propagation scenarios: (i) a uniform environment, and (ii) a Gaussian environment. For the latter, three angular spreads (AS) of 20˚, 30˚, and 40˚ and incident angle of every 10˚ in both elevation and azimuth coordinates are considered. The resulting ECC in the uniform environment is below 0.15 over the entire operating frequency band, indicating that the 14 elements are minimally correlated. However, in a Gaussian environment, the ECC is evaluated at 3.25 GHz. For the AS values of 20˚, 30˚, and 40˚. The average number of ECC values below the 0.3 threshold is 48, 67, and 81 out of 91 total ECC values, respectively. Finally, a relation is derived between the number of ECC values below 0.3 and the lowly-correlated number of antenna elements. It is seen that at a wider angular spread of 40˚, the number of equivalent lowly-correlated elements is 12 with 87% from all considered incident wave directions.

This paper investigates the design method, characterization, and innovative uncertainty analysis of bandpass (BP) type negative group delay (NGD) passive cell. The lumped passive topology under study consists of a resistor and a passive RLC-series network. The voltage transfer function (VTF) based circuit theory introducing the BP NGD specification analytical expressions is established in function of the R, L and C lumped component parameters. The BP NGD performance is evaluated by figure of merit (FOM) formula. To demonstrate the BP NGD function, the design method was applied to a proof-of-concept (POC) operating at 125-kHz RFID standard center frequency. The BP NGD theory is validated by both AC simulation and measurement of POC and discrete component-based circuit prototype. Experimental BP NGD results in good agreement with calculation and simulation are obtained with NGD value of -36.77 μs, 8% NGD bandwidth, and an attenuation lower than -9.6 dB. Innovative expressions of BP NGD parameter uncertainties are established versus the POC circuit parameters. The BP NGD specification variations are interpreted with respect to the influence of constituting component uncertainties via comparison between the established NGD uncertainty theory and co-simulated sensitivity analyses.

In application to active microwave remote sensing, the counterwise RL (left-hand circularly polarized transmitting and right-hand circularly polarized receiving) and LR polarized bistatic scattering are generally stronger than the likewise LL and RR ones, respectively. In this paper, we investigate the circularly polarized propagation over terrain profile at 1.575 GHz and 900 MHz in application to wireless communication. Completely different from common sense in remote sensing, however, numerical simulations show that field strengths for likewise polarizations are larger than those for counterwise polarizations. For further verification, circularly polarized bistatic scattering from terrain is also provided, which is consistent with previous conclusion that the counterwise LR polarized one is larger. Physical mechanism of such a contradictory behavior is explicated by local Fresnel reflections, and physical insights are offered for terrain propagation of circular polarizations. It is suggested that the likewise configuration be adopted in wireless communication, although the counterwise is adopted in microwave remote sensing.

This paper presents the design of a Super Wideband (SWB) antenna with enhanced bandwidth for microwave application with a detailed parametric study of the methods used to enhance the bandwidth of the conventional antenna. The proposed SWB antenna has emerged from a traditional circular monopole antenna by experimenting with the inscribed fractal structure with a tapered feed line and partial ground plane with blended corners and achieved a super wideband frequency range from 2.31 GHz to 105.5 GHz with a fractional bandwidth 192.1%, Bandwidth Dimension Ratio (BDR) 2154.88. The antenna has a relatively small electrical dimension i.e. 0.33λ₀x0.27λ₀, where λ₀ corresponds to the lower-end operating frequency and exhibits good gain and efficiency characteristics. In order to observe the signal correlation of the proposed antenna, the time domain analysis using similar antennas in face-to-face and side-to-side scenarios has been performed using the EM simulation tool CST-STUDIO. The simulated gain varies from 1.28 to 9.35 dBi. The proposed antenna can be used for S, C, X, Ka, Ku, V and W bands for microwave and millimetre wave applications. The simulated and measured results of the proposed antenna exhibit a good agreement.

Aiming at the problem of excessive torque ripple of switched reluctance motor (SRM), a three-interval PWM duty cycle adaptive control strategy is proposed in this paper. The method changes the PWM duty cycle to adjust the voltage across the windings according to the torque error, divides the interval according to the inductance linear model, and adapts to different PWM duty cycles in different intervals, different speeds, and different torque errors. And the optimal PWM duty cycle group under different rotation speeds is obtained by trial and error, and this duty cycle group is used as the control method to adapt the PWM duty cycle group. Finally, through Matlab/Simulink simulation and motor platform experiments, the three-interval fixed PWM duty cycle control strategy and the three-interval PWM duty cycle adaptive control strategy in this paper are compared. The results show that the three-interval PWM duty cycle adaptive control strategy proposed in this paper has a good torque ripple suppression effect in a wide speed and wide load range.

An ultra-wideband (UWB) antenna with dual band notched characteristics verified by characteristic mode analysis (CMA) is presented. The intended UWB radiator is etched on a Rogers RT5880 substrate with a size of 29×35×0.764 mm³, operating over a spectrum of 2.66-14.86 GHz with a fractional bandwidth (FBW) of 139%. Dual notched bands at WiMAX (3.01-3.63 GHz) and WLAN (4.48-5.85 GHz) are achieved by embedding L-shaped stubs in the notched rectangular patch. In addition, the two notched bands of the reported antenna are verified by using characteristic mode analysis (CMA) in terms of modal significance (MS) and characteristic angle (CA). The reported antenna's simulated and tested results are well matched to obtain S₁₁, VSWR, stable radiation patterns, a stable peak gain of 2.65 to 3.6 dBi and the maximum radiation efficiency of 97.86% in frequency domain, which makes the intended radiator suitable for portable UWB applications.

A novel dual-band filter power divider (DB-FPD) with controllable transmission zeros (TZs) is designed using a slotline multimode resonator (SLMR) in this letter. Using the stub loading technology, each resonator mode of the SLMR can be easily controlled. Accordingly, a dual-band bandpass filter is realized. Four TZs are generated due to the loaded stubs on the SLMR and feeding network, which can improve the out-of-band selectivity. Finally, without introducing additional circuits, a DB-FPD with good performance is realized. For verification, a prototype operating at 2.01 and 4.79 GHz is fabricated and measured. The measured results are basically consistent with simulated ones. The 3-dB fractional bandwidths are 29.7% (1.72~2.32 GHz) and 7.99% (4.58~4.96 GHz), respectively, and the isolation in each band is better than 14 dB.

A flux weakening (FW) control method of leading angle for a permanent magnet synchronous motor (PMSM) based on active disturbance rejection control (ADRC) is proposed to solve the problem of large fluctuation of speed, current, and torque in the control process. Firstly, according to the mathematical model of PMSM and its voltage and current constraints, the leading angle FW control algorithm is introduced. Then, according to the ADRC theory and the mathematical model of PMSM, the speed loop ADRC and current loop ADRC are constructed. The controller parameters are combined with the control bandwidth, and the parameter variation ranges are obtained by analyzing the stability of the control system. Finally, the proposed ADRC methods are combined with the leading angle FW control method to realize the ADRC leading angle FW control for PMSM, and the proposed method is verified on the experimental platform. The experimental results show that the proposed method has less speed, current, and torque fluctuations than the proportional integral (PI) controller method, which can effectively improve the motor control performance. At the same time, the controller parameters are combined with the bandwidth, which is convenient for practical engineering application.

This paper reports a novel, cost effective, and compact ultra-wideband (UWB) antenna for applications in an unlicensed-frequency band of 3.1-10.6 GHz. To achieve the UWB operation, a novel concept of annular shapes, circular slot combinations, and partial ground is employed. Furthermore, the proposed antenna with novel configuration occupies an attractive size of only 18×12 mm² which allows compatibility with portable UWB application devices. This flower-horn shaped UWB antenna is printed on a cost-effective FR-4 substrate, which exhibits a dielectric-constant of 4.4 and a loss-tangent of 0.019. The fabricated prototype is experimentally tested, and measured results validate the design approach of presented UWB antenna. The measured results confirm its UWB characteristics covering 3.1-11.2 GHz with S₁₁ ≤ -10 dB. Also, a maximum peak-gain of 5.05 dBi at 9 GHz and a minimum radiation-efficiency of 94.35% are noted in the full operating-band. A good agreement has been obtained between the simulated and measured results in terms of reflection-coefficient, gain, radiation-efficiency, radiation patterns and group delay which confirm the suitability of suggested small printed antenna for the intended UWB applications.

In this paper, a dual-band ultra-wideband conformal antenna for Wireless Capsule Endoscopy is proposed. The antenna uses polyimide as a substrate of side wall to achieve conformality, leaving space for other components of the Wireless Capsule Endoscopy. The feeding network of the conformal antenna utilizes the circuit characteristics of Complementary Split-Ring Resonator to achieve dual-band operation at 1.4 GHz and 4.0 GHz. Based on the principle of wideband characteristics of spiral antennas, the conformal antenna radiation structure is improved. A short-pin is loaded at an appropriate position to improve the impedance matching of the antenna and achieve ultra-wideband without changing the resonant points of the antenna. The operating bandwidth of the antenna can reach 30.3% (1.20~1.63 GHz) and 53.3% (3.33~5.75 GHz), respectively. In addition, the antenna is placed in different simulation models to verify the stability of its operation. Minced pork is used to verify effectiveness of the conformal antenna. The measured results show that the proposed antenna is suitable for capsule endoscopy.