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Cyber–physical cloud systems (CPCS) are integrations of cyber–physical systems (CPS) and cloud computing infrastructures. Integrating CPS into cloud computing infrastructures could improve the performance in many aspects. However, new reliability and security challenges are also introduced. This fact highlights the need to develop novel methodologies to tackle these challenges in CPCS. To this end, this article is oriented toward enhancing the soft-error reliability of real-time workflows on CPCS while satisfying the lifetime reliability, security, and real-time constraints. In this article, we propose a dependable algorithm for scheduling workflow applications on CPCS. The proposed algorithm uses slack to recover failed tasks and allows all tasks to share the available slack in the system. To improve soft-error reliability, the algorithm first determines the priority of tasks, then assigns the maximum frequency to each task, and finally assigns the recoveries to tasks dynamically. Slack also can be used to utilize security services for satisfying system security requirements. The lifetime reliability constraint is met by dynamically scaling down the operating frequency of low-priority tasks. Extensive experiments on real-world workflow benchmarks demonstrate that the proposed scheme reduces the probability of failure by up to $52.1\%$ and improves the scheduling feasibility by up to $83.5\%$ compared to a number of representative approaches.

In this paper a dual E–shaped patch (ESP) antenna is proposed to enhance the wider impedance bandwidth to be use for wireless communications in 5G applications. The proposed dual ESP antenna performance analysis is carried out with stub in this work. The proposed ESP antenna with stub achieving reflection coefficient below -10 dB for obtained multiple resonant bands. The dual ESP antenna operates at 5.7 GHz,10.1 GHz,15.1 GHz,19.4 GHz and 22.4 GHz obtain reflection coefficient of −44.32 dB, −27.43 dB, −17.0 dB, −50.85 dB and −18.07 dB respectively. The proposed antenna with stub achieves impedance bandwidth of (4.28 GHz–24.06 GHz) with 139.37% enhancement resonate at 19.77 GHz operating frequency. The radiation patterns, current distributions and gain plots are observed at five resonant bands. The simulated results are matched well with the measured results.

Textile materials used without any other structures show low absorption throughout the operating frequency range, and they are currently used for interior decoration. These fabrics can play an impo...

In this letter, we present a novel analysis and design approach of self-oscillation frequency (SOF) for 0.8- ${{\mu }}\text{m}$ indium phosphide (InP) double-heterojunction bipolar transistor (DHBT) emitter-coupled logic (ECL) and current-mode logic (CML) static frequency dividers. SOF of ECL and CML dividers is designed to be the maximum value after theoretical analysis and multiparameter optimization. The results show that the SOF of the ECL and CML divider is 62 and 37.5 GHz, respectively. With sinusoidal waveform input, the operating frequency range of the ECL divider is from 0.1 to 65 GHz, and CML is from 0.1 to 55 GHz, while the cut-off frequency ${f_{T}}$ is 150 GHz. For ECL, the ${f_{T}}$ utilization of SOF (SOF ${/}{f_{T}}$ ) is 0.413, and CML is 0.25. These are the maximum SOF results that can be designed for the two dividers under the same design conditions.

In this paper, we provide a tool for predicting the power transfer efficiency of radio-frequency (RF) wireless power transfer (WPT). With its capability of long-range wireless power transfer, RF WPT is considered as a very promising recharging technique for powering low-power internet of things (IoT) devices. The prediction of the power transfer efficiency is a prerequisite for setting up a proper design goal of RF WPT systems. We propose an analytic method that enables to calculate the efficiency in various multi-antenna-to-multi-antenna WPT scenarios with arbitrary positions and attitudes of antenna arrays. We have built a prototype RF WPT system with 64 transmit and 16 receive antennas, the operating frequency of which is 5.8 GHz, and verified the accuracy of the proposed analysis.

A rolling part is normally gone ahead to axle and mounted straightforwardly on a locomotive or by implication on a bogie in order to get the dynamic powers on the locomotive axle. The main goal is to figure out the natural and operating frequency of wheel axel of the locomotive for balancing those frequencies and keeping away from resonance by utilizing the vocal reaction, in this manner the vibrations of wheel axle of the locomotive may decreases. A 3D model of wheel axil of the locomotive is displayed in CATIA and brought into ANSYS programming to perform static, modular and dynamic investigation by utilizing various rates and materials to analyze power and dynamic attributes of wheel axle of the locomotive.

In this article, to reduce the operating frequency and the size of the spoof surface plasmon polariton (SSPP) attenuator and introduce the filtering function into the graphene attenuator, we propose a tunable graphene filtering attenuator, namely the graphene-based effective SSPP (ESSPP) attenuator. It consists of an ESSPP waveguide and a graphene sandwich structure (GSS). The effect of GSS on the attenuation and dimensions of the ESSPP waveguide on the passband are analyzed in detail, and the closed form of the attenuation is proposed. Finally, five prototypes of the graphene filtering attenuator are fabricated and measured. The experimental results show that not only the attenuation of this attenuator can be tuned but also that the upper and lower cutoff frequencies can be adjusted independently, which means that this filtering attenuator demonstrates expected filtering and attenuation performance.

In this letter, new compact third-order single- and dual-band filters on a hexa-modes half-mode substrate integrated waveguide (HMSIW) resonator with loaded H-shaped slot are presented. For the single-band design, the TE101 mode, TE201 mode, and the lower part of H-shaped slot mode are utilized to realize the third-order filtering response. By properly allocating the high-order modes, wide-stopband performance is also obtained. For the dual-band design, the TE101 mode, TE201 mode, and the lower part of H-shaped slot mode are used to realize the third-order lower passband, and the TE202 mode, TE302 mode, and the upper part of H-shaped slot mode are used to realize the third-order upper passband. The operating frequency and bandwidth of the proposed single-/dual-band filters both can be independently controlled. To validate the design concept, two prototypes of third-order single- and dual-band HMSIW bandpass filters (BPFs) are designed, fabricated, and tested. The simulated and measured results agree well with each other.

Monitoring multilayer dielectric structures for defects, such as disbonds and delaminations, is an ongoing issue in a number of critical applications. Chipless RFID tags can be used to address some of the issues pertinent to detecting these defects. This work explores the use of chipless RFID tags for this application and investigates the effects of tag operating frequency, material thickness, material dielectric properties, and delamination thickness on this approach's sensing capabilities. The benefits and challenges of this approach are discussed in the context of a collection of simulations and measurements using two new tag designs.

In this communication, a dual-polarized magneto-electric (ME) dipole antenna is implemented in the printed ridge gap waveguide (PRGW) technology. The antenna is composed of a cross-shaped ME-dipole backed by an artificial magnetic conductor (AMC) sidewall cavity. This cavity is fed by two orthogonal PRGWs implemented in two separate layers to achieve a dual-polarization with −28 dB isolation level at the center operating frequency (30 GHz). The proposed antenna achieves a 23.4% relative impedance bandwidth at 30 GHz with isolation better than 20 dB over the whole operating frequency band. In addition, a gain enhancement technique is used to increase the gain to 10 dB over the operating bandwidth. A prototype is fabricated and there is a good agreement between simulated and measured results.

The electric component of the RF field at the input of the traveling wave accelerating structure (operating frequency of 2856 MHz) of the LUE-200 linear electron accelerator – a driver for the pulsed source of the IREN facility developed at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research (Dubna, Russia) – is considered. The estimates of the focusing effect of the RF field on the nonrelativistic electron beam injected into the structure after the buncher performed for the thin electric lens model have shown that the focusing effect of the edge RF field for the beam particles turns out to be sufficiently rigid.

An improved high frequency programmable counter is presented in this brief in realizing divider circuit for frequency synthesizers. The core improvement is based on modification of control architecture in End of Count (EOC) configuration. The overall architecture of the counter shows a speed improvement of more than 24% compared to its predecessor. The design is implemented in 65 nm CMOS technology with silicon occupancy of $42\times 78\,\,\mu \text{m}^{2}$ , consuming total power of 0.68 mW, at its highest operating frequency of 7.1 GHz in 1.2 V supply. The divider achieves full modulus of 255 with minimum division ratio of 5 at its highest frequency.

Generally, the magnetic field profile in the gyrotron beam–wave interaction section is usually considered to be constant in the theoretical investigation, but actually it is approximately linearly tilted slightly due to the limitation of the superconducting magnet coils. The effects of the weak operating magnetic field taper on the operating frequency, the beam–wave interaction efficiency, and the frequency-tuning range for a continuously frequency-tunable gyrotron are investigated with a self-consistent nonlinear beam–wave interaction theory. It is found that the tapered operating magnetic field has a significant effect on the operating frequency, the frequency tuning bandwidth, and the beam–wave interaction efficiency. In addition, the effect of the weak operating magnetic field taper on the starting current is studied based on the linear theory. It is found that the values of not only the starting current but also the operating magnetic field are obviously different from those when the tapered operating magnetic field is taken into account. With the increase in the slope of the tapered operating magnetic field, the operating frequency and the frequency-tuning range are decreased, but the beam–wave interaction efficiency is increased. When the slope of the tapered operating magnetic field is negative, the variations in the operating frequency, the frequency-tuning range, and the beam–wave interaction efficiency are more obvious. The effects of the tapered magnetic field on different order axial modes are different, and the effect on a higher order axial mode is more notable.

A self-biased adaptive reconfigurable rectenna, consisting of a microstrip patch antenna and a self-biased reconfigurable rectifying circuit, is proposed in this letter. To eliminate the need of bias networks, a dc power routing structure is introduced to link the reconfigurable matching stub and the load. Hence, the output dc current obtained by the rectifier can be divided/split, thereby letting a part of the dc current flow back to the matching stub for providing a bias voltage. According to the input power level, the states of the p-i-n switch can be automatically changed in order to connect/disconnect the matching stub to the rectifying circuit for achieving improved matching performance at different power levels. Simulated and measured results show that the proposed rectenna reaches more than 50% conversion efficiency over a broadened input power range from 0–20 dBm with the peak efficiency of 68% at 9 dBm. It is evident that the proposed self-biased reconfigurable matching scheme is a promising and effective solution to facilitate the less-complicated reconfigurable rectenna integration and realize high efficiency at higher operating frequency bands (e.g., >5 GHz).

Advanced Internet-of-Things applications require control-oriented codes to be executed with low latency for fast responsivity while their advanced signal processing and decision making tasks require computational capabilities. For this context, we propose three multi-issue core designs featuring an exposed datapath architecture with high performance, while retaining energy-efficiency. These features are achieved with exploitation of instruction-level parallelism, fast branching and the use of an instruction register file. With benchmarks in control-flow and signal processing application domains we measured in the best case 64% reduced energy consumption compared to a state-of-the-art RISC core, while consuming less silicon area. A high-performance design point reaches nearly 2.6 GHz operating frequency in the best case, over 2× improvement, while simultaneously achieving a 14% improvement in system energy-delay product.

This paper deals with the measurement of electromagnetic field parameters near high voltage systems, characteristics of electric field, magnetic field and electromagnetic field, as well as the possibilities of implementing measures to reduce the emitted electromagnetic field. The paper describes the measurement of electromagnetic field parameters in the vicinity of high voltage systems, the analysis and synthesis of the measurement results in the external and internal environment of particular transformer stations is evaluated. The objects of interest in these measurements were brick transformer stations for transforming AC voltage from 22 kV to 400 V and 230 V at the operating frequency of 50 Hz. With regard to the influence of electromagnetic fields in the environment, individual measurements were assessed in accordance with selected criteria.

In this work, a double gate drain extended metal–oxide–semiconductor (DG DeMOS) device has been investigated. Second gate is considered at body side of conventional drain extended MOS (Conv. DeMOS) which helps to enhance the on-state current of DG DeMOS. The study of both the devices has been carried out using the Sentaurus simulator. In the simulation studies, all the dimensions and doping parameters of both devices have been kept the same except gate length and channel doping. The simulation studies have shown a significant improvement in DG DeMOS device parameters in comparison to the Conv. DeMOS device. The DG DeMOS device provides high breakdown voltage, low on-resistance, low gate capacitance (Cgg), low gate to drain capacitance (Cgd), high cut-off frequency (Ft) and maximum operating frequency (Fmax) and better trans-conductance and intrinsic power gain (S21) as compared to Conv. DeMOS device. These features make the DG DeMOS device an excellent candidate for RF applications.

We propose and analyze metasurface-bound invisible (nonscattering) partially open cavities where the inside field distribution can be engineered. It is demonstrated both theoretically and experimentally, that the cavities exhibit unidirectional invisibility at the operating frequency with enhanced or suppressed field at different positions inside the cavity volume. The nonscattering mode excited in the proposed cavity is driven by the incident wave and resembles an ideal bound state in the continuum of electromagnetic frequency spectrum. In contrast to known bound states in the continuum, the mode can stay localized in the cavity infinitely long, provided that the incident wave illuminates the cavity. The nonscattering properties can be exploited for a straightforward implementation of multi-layer resonators with adaptive field localization. Several examples of applications of the designed cavities are proposed and analyzed, in particular, cloaking sensors and obstacles, enhancement of emission, and “invisible waveguides.”

The scheme and components of a wide field-of-view meter-wavelength radio telescope prototype developed based on an antenna array consisting of 128 dipoles is described. The operating frequency range is 38–74 MHz. Main parameters of the future prototype are presented and versions of its development are discussed.

In this article, a novel tunable attenuator based on graphene is proposed. It consists of a coupled microstrip line (CMSL) and two graphene-covered gaps in MSLs. By utilizing a biased voltage, the surface impedance of graphene can be tuned, and then, the reflective coefficient at two ports of the coupler can be correspondingly adjusted; therefore, the performance of the attenuator can be modified. The design procedure and the mechanism of the attenuator are demonstrated in detail. To verify the analysis, a prototype was fabricated and tested. According to the measured results, the fabricated attenuator presents the favorable attenuation tuning range from 3 to 20 dB at the operating frequency from 1 to 6 GHz, and it is just 38 mm $\times22$ mm in size. Besides, $\vert S_{11}\vert $ of the attenuator can always be maintained at a low level, and the phase of $S_{21}$ is substantially unchanged.

Video display processing is an indispensable module in a variety of multimedia systems. With the increase of video format to 4K $\times$ 2K@60fps, the design of efficient display processing circuit faces severe challenges. This paper presents a video display processor which supports a variety of video formats and integrates multiple advanced algorithms for perpetual image quality improvement. By leveraging algorithm and architecture co-design, this paper efficiently implements these computational and memory intensive display processing algorithms in a single chip. In particular, we describe three representative design modules in detail, including motion compensated frame rate up-conversion, content-adaptive contrast enhancement, and backlight local dimming. Extensive experiments demonstrate that the proposed design modules outperform the previous works in terms of either image quality or hardware efficiency. The overall chip is fabricated in GF 55nm CMOS technology, and can work at the maximum operating frequency of 594 MHz. The maximum input and output video formats reach up to 4K $\times$ 2K@60fps.

Energy-optimal operation is one of the key requirements of the Internet-of-Things (IoT) applications to increase battery life. In this article, using a combination of dynamic voltage scaling (DVS) and adaptive body biasing (ABB), the energy-optimal operation is achieved with a given fixed operating frequency determined by application demands. Based on the observation that the ratio of leakage power to dynamic power can be an accurate indicator for the optimal operating point, the proposed method dynamically tracks the minimum energy operating points by adjusting supply voltage and body bias with very low hardware and power overhead. A custom dc–dc converter for supply voltage regulation and charge pumps for body bias generation were implemented with the proposed method in a Cortex-M0 processor. Since SRAM is included in the same energy optimization loop as the processor, a custom SRAM was designed to match the processor speed. The design is fabricated in an Mie Fujitsu Semiconductor (MIFS) 55-nm deeply depleted channel (DDC) CMOS and the proposed approach achieves energy consumption within 4.6% of optimal at 1 MHz across five process corners and temperatures from −20 °C to 125 °C. The fabricated processor achieves 6.4 pJ/cycle at 0.55-V and 500-kHz clock frequency.

A multilayer ultrawideband circuit analog absorber is proposed in this letter. The absorber comprises three layers: two absorbing layers and a metal ground layer. With the whole profile unchanged, the effects of the air spaces between absorbing layers on bandwidth enhancement are mainly addressed. The equivalent circuit is employed to analyze the appearance of reflection maximum poles, which limit the absorption at high frequencies. Based on the optimal equivalent circuit, two single-polarization perforated absorbing layers consisting of interdigital capacitors, meander lines, and lumped resistors are designed to achieve an ultrawide absorption band. For demonstration, a multilayer absorber is manufactured to validate the approach, where a bandwidth ratio of 1: 12.88 with a total profile of $0.101\lambda _{L}$ at the lowest operating frequency is achieved under normal incidence. The simulated results are experimentally verified by the measured results.

A compact planar simple configuration four band antenna for GNSS/WLAN/X-band operation is discussed in this article. The antenna comprise of a λ 4 rectangular slot in the radiating part and a rectangular slot at the ground plane. The inclusions of these slots helps the proposed antenna in achieving better gain and impedance matching. The antenna has a miniature size of 0.21 λ 0 × 0.21 λ 0 × 0.008 λ 0 where λ 0 is the free space wavelength at the lower operating frequency of 1.6 GHz. The antenna shows operating performance at 1.6 (GNSS)/5.7 (WLAN)/7.1/7.8 (X-band) with S11

An autonomous and continuously operating Radio Frequency Identification (RFID) temperature sensor is designed, manufactured, and tested. This sensor is battery-free and can detect temperature threshold crossings for multiple (room-to-cold and cold-to-room) temperature cycles, respectively. The proposed sensor conveys temperature threshold crossings through the controlled switching of its operating frequency within the 902-928 MHz Ultra High Frequency (UHF) RFID band. For the first time, shape morphing cold-temperature reactive Liquid Crystal Elastomers (LCEs), which provide reversible actuation, are utilized. The proposed sensor design consists of a patch antenna with a customized slot. A passive mechanical switch is connected across this slot and provides the frequency switching as it is activated and deactivated. The integration of this switch with the antenna is achieved using a co-simulation method. Furthermore, the cold-temperature reactive LCE triggers the switch when a temperature violation has occurred, thereby switching the operating frequency of the sensor based on temperature changes. Additionally, a high-dielectric constant substrate and a single matching network that operates at two discrete frequencies are used to design our compact frequency-domain temperature sensor. Moreover, based on the RFID platform, this sensor operates effectively in close-proximity to other sensors. Also, is provides identification and temperature information through an autonomous, continuous, and cost-effective design. Therefore, the proposed sensor has the potential for operation in the Internet of Things (IoTs) applications, where large amounts of data is collected from numerous sensors to extract valuable information for the benefit of users, manufacturers, and delivery companies in the virtual domain of the internet. Finally, ANSYS HFSS and Circuit Designer are used for the simulation modeling. The performance of our sensor is validated using measurements and simulations that agree very well.

This paper proposes a stepped-width spiral antenna for gain enhancement at a low operating frequency. The frequency-dependent characteristic of the stepped-width transmission line is applie...

A novel approach to designing rectenna systems by eliminating the use of a matching network between the antenna and the rectifier is presented. The proposed rectenna consists of a wide impedance bandwidth 8 octagon disks placed at two different layers laying on both sides of a single substrate and backed by a ground plane. A Schottky diode is placed at each layer right at the feeding location without matching network, forming an array of two rectennas. The rectified power is smoothed out using a low pass filter composed of two RF choke inductors for each rectenna. By virtue of the wide impedance bandwidth of the antenna, the measurement results of the rectenna yielded a 50% radiation to DC efficiency at the operating frequency of 2.1 GHz. The rectifiers were then connected in series or parallel to study the effect of the connection type on the rectified output power. Wideband load resistance response and configurable amount of output DC currents and voltages can be realized using certain DC power combining methods.

In this paper, a water antenna has been designed to generate tunable orbital angular momentum (OAM) vortex wave. With a revisiting theoretical analysis about radiation characteristic of the shorted ring patch fed by two probes, a frequency dependent single shorted ring water antenna is designed. With the increase of the operating frequency, the single-ring water antenna can radiate the OAM waves with the changeable modes. Furthermore, a dual shorted ring water antenna is proposed. With a tunable feeding network, the OAM waves with the reconfigurable modes including the l = 1, l = 2 and mixed modes can be radiated by adjusting ON/OFF states of the PIN diode. The prototype of the dual-ring water antenna is fabricated and measured. Good agreement between the simulation and the measurement demonstrates that the overlapped bandwidth for three states covers 2.35~2.55 GHz with a good mode purity.

Biosensors antenna can be applied to the human body such as for health monitoring, diagnosis, and treatment. This research proposes a microstrip antenna that is applied for biosensing applications. The proposed antenna operates in the Industrial Scientific Medicine (ISM) band (2.4-2.5 GHz). In this study, the antenna is designed using the proximity coupled feeding technique. The proposed antenna is designed using CST Software. The antenna was fabricated and measured using the Pocket Vector Network Analyzer (VNA) device. The antenna substrate material used is Roger 3010 with a thickness of 1.28 mm. The results of the proposed antenna simulation show that the operating frequency is 2.46 GHz, S11 is -19.76 dB, and the bandwidth is 401.2 MHz. Meanwhile, the results of the fabricated antenna measurements show the operating frequency at 2.5 GHz with an S11 of -21.55 dB. Based on the comparison graph between the simulation and the measurement results, it can be concluded that the fabricated antenna has experienced an increasing shift frequency compared to the simulation results.

We report a terahertz quantum cascade laser frequency comb (THz QCL FC) with low threshold current density, high power, and wide current dynamic range. The active region design with the semi-insulated surface plasma waveguide is beneficial to optimize the gain dispersion value and temperature stability. At 10K, the comb with 3-mm-long and 150-µm-wide is capable of emitting 22mW with the threshold current density Jth = 64.4 A·cm−2. The total spectral emission is of about 300 GHz centered around 4.6 THz. Without any extra dispersion compensation measures, the intermode beatnote map reveals stable frequency comb operating within a current dynamic range more than 97% and the narrowest beatnote linewidth is 7.2 kHz. The stable FC operation of a free-running THz QCL makes our device an ideal source for further development of dual-comb spectroscopy.

Design and testing results of I/Q mixer and voltage-controlled oscillator IP-blocks for application in 5G communications are presented. IP-blocks were implemented in a commercial 0.42/0.25 μm SiGe BiCMOS process. The test results demonstrate that designed mixer has a conversion gain of more than 5.5 dB in the operating RF frequency range from 25.5 GHz to 26.5 GHz and IF frequency range from 1 GHz to 2 GHz, power consumption less than 235 mW. The designed voltage-controlled oscillator has an operating frequency range from 20.8 GHz to 24.6 GHz in the control voltage range from 0 V to 4 V, the output power is not less than 6 dBm, power consumption is less than 116 mW.

The results of the theoretical study of the influence of grating thermal expansion on the clinotron radiation frequency has been presented and compared with the experimental data. The external system controlling a chiller for the clinotron grating temperature stability has been developed and tested. The experimental study showed the effective tuning and control of the operating frequency of the Clinotron tubes by varying the cooling water temperature.

This paper presents a technique to compensate the intrinsic loss of a tunable resonator, which can then be used to realize tunable bandpass filters (BPFs) with reduced insertion loss (IL). The parasitic losses in a tunable resonator can be compensated by introducing a negative resistance to the resonator through parametric amplification. Based on the proposed technique, a third-order tunable BPF operating between 1.5 to 2 GHz is designed and simulated. The simulated results indicate that the intrinsic loss can be compensated at each operating frequency. The compensated intrinsic losses are 11.9, 9, and 7.2 dB at 1.5, 1.75, and 2 GHz, respectively. In addition, the resulted noise figure, out-of-band rejection, and return loss are all improved when the parametric amplification technique is applied.

Operating frequency of class E power amplifier with $\pi$ network is analyzed. Based on principle of class E, theoretical analysis shows that perating frequency is adjustable, waveform of current and voltage across switch is shown in time domain.

A multi-band metasurface has been proposed. Simulated and experimental absorption characteristics of the designed metasurface are studied. We demonstrate that the proposed metasurface can realize multi-band resonant absorption and high quality factor. The refractive index sensing performance of the metasurface is also investigated. The results show that the operating frequency of resonant absorption peaks shifts linearly with the refractive index of analytes increasing, which indicates that the designed multi-band metasurface can be applied for refractive index sensing.

For many modern communication systems nowadays we require cost effective with lower dimensional antennas. Micro-strip fix reception apparatuses speak to one group of minimized radio wires that offers the advantages of a conformal nature and the ability of prepared mix with a correspondence framework’s printed hardware. The different concept of feed is introducing over here because of its unique importance. So, it can be either feed by coaxial probe method or we can also use the inset micro-strip line. It is more useful as a narrow band application and that is the main reason according to its applications so it can be more applicable as a printed resonant antenna. In this paper, for the Bluetooth application, a patch antenna, using inset feed has been implemented using CST microwave Studio with its operating frequency 2.4 GHz.

Improvement of smart cities functioning models use a variety of modern technologies, such as the Internet of Things (IoT) and complex systems for merging and processing large data aimed to make decisions on safety, security and better quality of life. An important point of different systems modelling is taking into account the technology pros and cons and, where possible, combining technologies to reduce the human-harmful effects and gain more benefits from all them. This article proposes method for smart cities transport development based on the IoT concept. For ground and air vehicles detection it is proposed to use the forward scattering (FS) effect principle. This effect is the basis of forward scattering radars (FSR) and can be applied to detect moving objects in the multi-sensor network of the IoT. An example of vehicles detection using a GPS-FS system is used in the article. The hypothesis of the study is that the increase in the number of the IoT sensors in the future as well as their operating frequency will allow the detection of relatively small mobile objects. Also, the proposed method for vehicle detection and classification will not pollute the radio with additional signals because it will use only the available ones. This technology also benefits the protection of the environment from radio pollution.

This paper presents design and results of modeling a subarray of a multibeam antenna array with a co-phased power scheme. The proposed subarray is a linear array of four printed dipole antennas with a horn-shaped reflector, and a power circuit based on a four-channel strip power divider. Its operating frequency band on the level of VSWR less than 2 is in the range from 2.00 to 2.32 GHz. The realized gain is in the range from 12.0 to 12.5 dB.

Inductive power transfer (IPT) technology has been extensively studied for electric vehicles (EV) in the past decades. However, it has not drawn much attention in railway application. Due to the unique requirements of the railway system, most of the EV coupler designs are not directly compatible with wireless charging applications for a train. To fill this technical gap, this paper discusses the design considerations for railway application and introduces a design of a modular 5-kW IPT system for rail locomotives. According to the design constraints, a novel W-I coupler is proposed for the 5-kW IPT system and the system is optimized via ANSYS Maxwell. A prototype of the proposed IPT system is developed at an airgap of 5 inches and 85 kHz operating frequency. The prototype has been validated in a 1.7 kW output power supply with a DC to DC efficiency of 85.6%. The experimental results validate the feasibility of the IPT system design for rail application.

In this study, we focus on data sorting, which is a basic arithmetic operation, and we present a sorting library that can be used with the OpenCL programming model for field-programmable gate arrays (FPGAs). Our sorting library is built by combining three hardware sorting algorithms. It consumes more than twice the overall hardware resources compared to the merge sort restructured for the OpenCL programming model for FPGAs. However, its operating frequency is 1.09x higher and its sorting throughput is three orders of magnitude greater than the baseline.

A focused transmitarray antenna is presented in this Letter. To appraise the antenna, a quad-metallic-layer focused transmitarray antenna using I-shaped all-metal slot elements with an air gap between every two layers has been analysed, simulated and measured. It is illustrated that the electric field strength value at a distance of 3.1λ0 from the transmitarray antenna reaches a maximum at 9.3 GHz operating frequency. It is the first time that a focal plane of approximately one wavelength has been achieved with a focused transmitarray antenna consisting of all-metal elements. Simulated and measured results show that the proposed antenna has good concordance, making it possible for microwave measurements.

In this letter, a dual-band switchable MMIC star mixer is proposed. The MMIC is fabricated in a 0.1- $\mu \text{m}$ commercial GaAs pHEMT process with a chip size of 1.1 mm $\times1.3$ mm. The operating frequency band can be switched between 43–63 GHz and 55–85 GHz by changing the effective length of Marchand balun. Band selection is controlled by the bias voltage of pHEMT switches. The measurements show the conversion loss of 7–10 dB over the lower band and 10.5–13 dB over the higher band. The RF-to-local oscillator (LO) isolation has also been measured to be over 35 dBc. The modified star mixer can be used for dual-band millimeter-wave wireless communication or radar application.

A novel optically-induced dielectrophoretic (ODEP) device incorporating a gold nanofilm is proposed for the manipulation of microparticles. The electrokinetic phenomena induced under different optical radial images are investigated both numerically and experimentally. The results show that the gold nanofilm not only extends the operating frequency of the ODEP device, but also prompts a change in the direction of the DEP force from the outward direction to the inward direction at high frequencies. Consequently, particle concentration can be achieved in the high frequency range. Overall, the proposed device provides a bi-directional and velocity/force-controllable approach for the manipulation of microparticles in ODEP applications.

This paper presents an area-efficient current-mode-logic (CML)-based divider, with a tunable self-resonant frequency for locking range (LR) extension. Specifically, a negative- $g_{m}$ (NG) cell is inserted between the resonated shunt-peaking inductor and the load resistor to shift the divider’s sensitivity curve (SC), enabling concurrently a higher operating frequency and a wider LR. We also use the injection-locking concept, together with a graphical phasor diagram with the frequency-phase information, to systematically explain the LR-extension mechanism. Prototyped in a 65-nm CMOS, the divider occupies a tiny active area of 0.0018 mm2. The measured LR is 153% (4–30 GHz) while consuming 4.06–4.28 mW at 30 GHz under a single 1.2-V supply. The performance corresponds to two figure of merits: FOM $_{\mathbf {Pdc}}$ of 25.5 dB and FOM $_{P}$ of 71.5, both compare favorably with the state of the art.

Voltage controlled oscillator (VCO) is one of the most crucial components in nanometer-scale circuits for communication systems. Wide tuning range, low power demand and high operating frequency are...

We present a new acoustic metasurface structure to generate the stable acoustic vortex beams with controllable topological charge in the broadening of operating frequency. The proposed acoustic metasurface can dynamically achieve a full span of 360° phase modulation by three simple solutions. Acoustic plane beam and acoustic vortex beam can convert each other based on multi-metasurfaces combination. Potential applications of such phase modulation schemes can be anticipated.

The paper examines the development and testing of an electro-pneumatic device for wound healing therapy after surgery in the neck area. The device generates air pressure values in a miniaturized cuff using electronic circuitry to drive an electro-valve and air compressor. The device works in two distinct modes: continuous pressure mode and pulsating pressure mode. The pressure value setting can vary from 3 to 11 mmHg, and the pulsating pressure mode’s operating frequency range is approximately 0.1 to 0.3 Hz. Laboratory measurements were conducted to evaluate the device’s correct functioning in both continuous and pulsating pressure modes. A four-day prospective study with animals (n = 10) was also conducted to evaluate neck wound healing therapy using the electro-pneumatic device. Out of the twelve histological parameters analysed to reveal the differences between the experimental and control wounds, only one demonstrated a significant difference. Out of the ten animals treated with the device, three showed a significant difference in terms of benefit after therapy. We can therefore conclude that the device potentially improves the wound healing process in the neck area if the pre-set air pressure value does not exceed 8 mmHg.

With the development of semiconductor process technology and circuit design capabilities, operating frequency of random access memory has been improved dramatically. Accurate measurement of embedded memory random access time is becoming a challenge, especially for low-density embedded memory. Traditional timing measurement which connects the external ports directly to the internal ports of memory is not feasible for its low efficiency and very low precision. A new method which applied the built-in test circuit to memory access timing measurement is presented in this paper. With high-speed static random access memory testing chip fabricated with 28 nm logic process, the proposed access timing measurement circuit has been verified and proved to be accurate.

In this article tunable characteristic of differentially fed inverted microstrip patch antenna is presented for C-band operation. Differential feeding is applied through a unilayer integrated coupler feed. Near the operating frequency of the designed antenna the fabricated coupler shows that the amplitude imbalance is 0.3 dB and phase imbalance corresponds to 3.2°. Tuning is achieved by changing the air gap height in the antenna structure from 1 to 4 mm. Proposed concept of tunablity is verified for two different patch geometries (circular and rectangular) and three different patch dimensions through analysis and experiments. Closed form expressions are proposed to predict the tuning frequency. This design offers low cross-polarized radiation in the H-plane and symmetric co-polarized radiation in both principal planes. Fabricated prototype is measured and compared with simulated and theoretical values. The comparison among the simulated values, theoretically computed values and the measured values for different air gap heights of 2, 3, and 4 mm, shows an error less than 1%.