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Single-inductor multi-port converters have great application potential due to their “more silicon less magnetic” feature. However, the recent topology design methods, such as the forward design and reverse design, require strong power electronics knowledge, which troubles the application engineers lacking power electronics background. In this paper, a topology deduction method based on Reinforcement Learning (RL) is proposed to gain the benefits of both forward and inverse design. The proposed method uses a neural network (NN) for forward design, and takes a set of simple rules to give rewards for reverse design. With RL, the NN sums up experience during trial-and-error without human intervention, and finally finds the topology that gains the highest reward. Benefits of this method include: (1) it only requires design specifications such as components and port voltage as inputs and some simple rules as rewards, avoiding complicated feature predesign; (2) it allows the deduction to be started from any pre-connection, satisfying the prior constraints of application engineers, and (3) it can recommend several actions at each step, providing good diversity of deduction results. Using this method, many topologies in the literatures are deduced, and some new topologies are also found. One of the topologies is experimentally tested and the results show the validity.

T-type three-level inverters have attracted extensive attention for their utility in many applications, especially photovoltaic power generation. For these inverters, parallel operation offers superior performance in efficiency, reliability, and scalability. However, the introduced circulating current (CC) may cause overcurrent in line, which seriously threatens the safety and stability of the system. The mechanism of CC lacks detailed analysis in single-phase modular inverters. Thus, an accurate mathematical model is established and a CC suppression method is proposed in this paper for parallel-operated single-phase T-type three-level inverters. Firstly, the characteristics of port degradation are analyzed, and an improved equivalent circuit is introduced based on the findings. Then, according to the improved equivalent circuit, a detailed mathematical model is established. Using this model, excitation sources of CC are analyzed and divided into three parts. After that, a CC suppression method involving carrier-based pulse width modulation with offset voltage injection is proposed, and a deadbeat controller is designed to calculate the offset voltage. Moreover, the proposed method can balance the neutral point voltage across DC-link capacitors as well. Simulation and experimental results validate the theoretical analysis and effectiveness of the proposed scheme.

Dual-row retaining walls can be utilised to form embankment structures for protection against tsunamis or as port structures. The dynamic response of these walls involves a complex interaction between the soil and structural elements which is not well understood. In this paper, for the first time a combination of centrifuge and finite-element modelling is used to better understand the mechanical response of the combined wall–soil system. The measured variation of the horizontal stresses leads to bending moment distributions featuring large, singly outward bending or double curvature with significant inward bending of the wall near the ground level. The numerical analyses are used to understand the stress state and highlight the dynamic variations of the vertical effective stress that drive this previously unexplained behaviour. The shear stresses that can develop at the wall–soil interface govern the mechanism by which the vertical effective stresses can vary. Further consideration of the dynamic soil stress state suggests a purer interpretation of the limiting loads in soil–structure interaction problems relative to the traditionally defined dynamic earth pressure coefficients. Combining the altered vertical soil stresses with earth pressure coefficients depending only on the soil friction angle adequately bounds the horizontal stresses that develop in the soil.

A multi-port converter with bipolar outputs to integrate renewable energy and energy storage into the bipolar dc bus is the desirable solution due to its high reliability and efficiency. A novel symmetric bipolar outputs full-bridge four-port converter based on phase-shift modulated buck-boost voltage balancer is proposed in this paper. The interleaved bidirectional buck/boost circuit with pulse width modulation is used as the primary side to achieve the integration of renewable energy and energy storage, while the phase-shift modulated buck-boost voltage balancer is derived as a secondary side circuit to generate a symmetrical and common ground bipolar output voltage. Single-stage power conversion, symmetrical bipolar output voltage, approximately decoupled control loop, and soft switching can be realized in the proposed four-port converter. Detailed analysis of the proposed converter is presented, including operation principle, steady-state performance, soft switching performance, and control method. Finally, experimental verifications are carried out to illustrate the feasibility and effectiveness of the proposed topology.

To construct the bipolar low-voltage dc distribution system, a dual-active-bridge (DAB) converter and a voltage balancer are needed. However, this conventional two-stage circuit is bulky and shows low efficiency. Besides, when a short circuit fault occurs at one of the bipolar dc poles, the conventional topology cannot balance the other normal dc pole voltage due to its single closed circuit, which eventually loses the high reliability of the bipolar system. To mitigate those issues, a modified three-port DAB converter is proposed. The proposed converter is an enhanced topology of the three-port DAB converter, which can balance the bipolar voltage levels without additional voltage balancers. In addition, each bipolar output has an independent closed circuit to balance the normal dc pole under the short circuit fault at one of the dc poles, thereby improving the system reliability. Moreover, constant duty-cycle modulation and magnetizing inductance design are proposed to obtain full-range ZVS of all switches. Since the proposed ZVS modulation uses a constant duty-cycle value, its control can be easily implemented in a digital signal processor. Finally, a 2-kW prototype is developed to validate the effectiveness of the proposed converter.

Since the dc-side fault in the multi-terminal dc grid propagates extremely fast, the fault current limiter (FCL) is essential to achieve fault ride-through of the healthy network. Current-limiting inductors (CLIs) are currently the most commonly used FCLs in projects that have been built, are under construction, or are planned. The CLIs can be designed based on the system requirements, such as converter fault ride-through and dc circuit breaker (DCCB) interrupting capacity. Unfortunately, the installation of CLIs has negative impacts on the system transient response and operational stability, the fault isolation speed and energy dissipation of DCCBs. To solve these problems, an economical bridge-type multiport fault current limiter (BT-MFCL) is proposed in this paper, which can be installed at the dc bus with multiple dc lines connected and can cooperate with the existing DCCBs. The BT-MFCL is composed of a CLI on each port and a shared energy dissipation circuit (EDC). The fault current can be limited by the embedded CLIs in the BT-MFCL without a time delay, while the EDC can eliminate the negative influences of CLIs. Extensive simulations and experiments have verified the effectiveness of the BT-MFCL. Besides, the performance comparison of the BT-MFCL with existing solutions is elaborated.

The Potential Transformer (PT) plays an important role in the measurement and monitoring of the power system. The accurate modeling of the PT is very important but not yet perfect. The stray capacitance will have a non-negligible effect on the performance of a PT. However, the influence of stray capacitance is rarely considered in existing models, which makes the broadband simulation performance weak and provides limited references in engineering. In this paper, a calculation method of PT stray capacitance is proposed to analyze the performance of the PT at different frequencies and extract the capacitive current of the PT port. This paper used a non-destructive method to obtain the test data of a PT, calculated the value of the stray capacitance, and drew the hysteresis loops of the iron core. A corresponding simulation model was established to predict the PT performance at different frequencies. The simulation results are in good agreement with the experimental data, which proves the accuracy of the modeling parameters. The data processing logic is clear and is easy to be simplified by programming, which makes it promising in engineering.

Most DC power distribution architectures are organized as a typical cascaded converter system that is composed of source and load converters, and may experience a system oscillation due to the negative impedance effect of constant power loads. The load-side virtual impedance method is a possible solution to such stability problem, which however makes the dynamic response of the load converter slow, and thus increases the requirement of the filter capacitance. In this paper, an auxiliary circuit that is connected to the output port of the load converter is proposed to enhance the transient performance of the power converter system, while the system can be stabilized by the virtual impedance method. The control and parameter design of the proposed auxiliary circuit is introduced. The capacitance requirement of the system for an expected transient deviation of the output voltage is significantly reduced by using the proposed auxiliary circuit. An example design is given to verify the feasibility of the proposed method with simulation analysis and experimental results.

In this note, a control framework is proposed to render a power electronic system passive by adopting the port-Hamiltonian (pH) systems theory. The system has a power electronic converter, either grid-tied or islanded. The control framework consists of a lossless interconnection block and three control channels. It makes the power converter behave as a virtual synchronous machine (VSM). The three channels are designed to, respectively, generate the frequency and the flux of the VSM and a third quantity that is necessary for forming the lossless interconnection. It is proven that the closed-loop system is passive without the need of assuming constant frequency, constant voltage, and/or constant loads. It is sufficient to only assume that the load can be described with a passive pH model. Hence, the proposed control framework is very generic.

This paper presents a novel method to design multiple-input multiple-output (MIMO) antennas based on characteristic mode analysis (CMA), which is different from utilizing individual excitation of each characteristic mode for high isolation. The CMA is performed to design a pair of symmetric slots on two connected dipole antennas (a MIMO dipole pair), so that two desired characteristic modes can be generated at the same frequency, one of which is in common mode and the other in differential mode. Hence, when one antenna element is excited, the two characteristic modes combine and cancel each other at the other antenna element, leading to high port isolation. The designed dipole pair is applied for use in 2G/3G/4G MIMO base-station arrays. Simulation and measurement results show that the antenna achieves a wide impedance bandwidth of 1.7-2.7 GHz (45.5%), low coupling below -20 dB, low cross-polarization below -20 dB, high efficiencies over 85%, and stable radiation patterns within the entire band. The results verified the advances of the proposed decoupling method, i.e., simplicity, effectiveness, wide bandwidth, good radiation, etc.

A hybrid analog-digital combiner for broadcast vehicular communication is proposed. It has an analog part that does not require any channel state information or feedback from the receiver, and a digital part that uses maximal ratio combining (MRC). We focus on designing the analog part of the combiner to optimize the received signal strength along all azimuth angles for robust periodic vehicle-to-vehicle (V2V) communication, in a scenario of one dominant component between the communicating vehicles (e.g., highway scenario). We show that the parameters of a previously suggested fully analog combiner solves the optimization problem of the analog part of the proposed hybrid combiner. Assuming $L$ directional antennas with uniform angular separation together with the special case of a two-port receiver, we show that it is optimal to combine groups of $\lceil L/2\rceil$ and $\lfloor L/2\rfloor$ antennas in analog domain and feed the output of each group to one digital port. This is shown to be optimal under a sufficient condition on the sidelobes level of the directional antenna. Moreover, we derive a performance bound for the hybrid combiner to guide the choice of antennas needed to meet the reliability requirements of the V2V communication links., 18 pages; 12 Figures; 2 Tables

A novel winding configuration named “integrated winding” was proposed to realize function of original two sets of windings, i.e. produces two independent-control magnetic fields with different pole-pairs (not slot-harmonics). The concrete realization method is through the coordinated operation of controllers, two current components with different phases are injected into the same coil to generate required magnetic fields according to star of slots. Because the magnetic field produced by the winding is only related to the instantaneous current in each coil, rather than specific connection of coils. The integrated winding not only simplifies the winding configuration, but also increases the electric loading, thus, improving torque density. The general method of integrated winding configuration and current injection rule are established. The split-phase rules of integrated winding are summarized and the feasibility of six-phase and twelve-phase integrated windings is then proved through finite element analysis (FEA). A prototype is fabricated and the experimental results verify the availability of the integrated winding.

In the acdcac converter system, the second harmonic current (SHC) is generated by the acdc rectifier and the dcac inverter. If the SHC propagates to the intermediate dcdc converter, the current stress of the power switches will be increased, and the conversion efficiency will be degraded. Therefore, it is necessary to suppress the SHC in the dcdc converter. In this paper, the generation and propagation mechanism of the SHC in the acdcac converter system is analyzed. Then, from a perspective of control bandwidth and dc-bus port impedance, the basic ideas for reducing the SHC in the dcdc converter with different control targets are proposed. Based on that, the virtual-impedance-based control scheme is proposed to increase the input impedance and output impedance of the dcdc converter simultaneously. The realization and design guideline of the virtual impedance are also presented. Finally, a single-phase 3-kVA acdcac converter system is fabricated and tested in the lab. The experimental results are provided to verify the effectiveness of the proposed SHC reduction control scheme.

This paper designs a class of low-profile compact MIMO antennas on a single radiating patch using simple and systematic characteristic modes (CMs) method. Rather than using conventional method of radiation pattern and polarization diversities, this work demonstrates that by taking advantage of a proper superposition of some even/odd modes, it is able to generate similar radiation pattern and polarization no matter which port is excited. It is also found that port isolation and impedance matching are dependent on not only operating modes but also input couplings. The proposed CMs method consists of three main steps. First, adjust desired even and odd modes to be equal in resonant frequency (ResF). Second, suppress unwanted modes without affecting desired ones. Lastly, determine feeding positions to obtain proper input couplings. In this way, satisfactory port isolation and impedance matching could be achieved simultaneously and quickly, getting rid of complicated decoupling structures and time-consuming optimization. To exemplify how the proposed CMs method works, two MIMO antennas are successfully designed by just using simple slots and shorting pins. A prototype for the proposed four-port MIMO antenna is fabricated and measured for validation.

Multi-port solid-state transformer (SST) characterized by high scalability is expected to be widely used in AC/DC hybrid microgrid. However, the DC bus voltage deviation and dynamic response speed are two key issues in its application. Therefore, a model predictive direct power control (MPDPC) of the three-port SST (TPSST) is proposed. Compared with the traditional PI-based method, the oscillation of the DC bus voltage is inhibited, and the steady-state performance is improved with the MPDPC method. Moreover, a direct power path is incorporated into the control system in order to integrate the rectifier and dual active bridge (DAB) stage. This power path delivers the power required by the load to the DAB stage and the rectifier stage for power control, thereby improving the dynamic response of the system in the process. Besides, since the MPDPC strategy is a control scheme for the whole system, the design of the control system is simplified. Finally, a low power prototype has been built and tested, and the experimental comparison with the traditional voltage control (TVC) and model predictive voltage control (MPVC) method verifies the efficiency improvement of the proposed control strategy.

This article presents a physics-based inversion technique for reliable characterization of droplets deposited by a liquid metal jetting additive manufacturing system, using an in-situ millimeter wave diagnostic. The overall approach is demonstrated in a custom droplet-on-demand liquid metal jetting system with effective droplet diameters ranging from 0.8 to 1.7 mm. The inversion results demonstrate that this approach can provide information about the droplet size and lift-off distance between the droplet and the diagnostic by monitoring the amplitude and phase of the reflection coefficient at the input port.

In this article, a novel 1.05-1.25 GHz filtering antenna feeding network with reconfigurable frequency and polarization is proposed. It simply consists of a reconfigurable in-/out-of-phase filtering power divider (RFPD) and a 90° hybrid coupler. By controlling the varactors in the RFPD without any switch component, the proposed 3-port feeding network offers continuous reconfigurable filtering responses with four switchable output patterns including: equal power dividing with phase difference of negative or positive 90°, single-ended output at either output port. With this proposed feeding network connecting to a regular dual-polarized antenna, the resulted antenna system can easily realize reconfigurable polarization of vertical polarization (V-LP), horizontal polarization(H-LP), left-handed circularly polarization (LHCP) and right-handed circularly polarization (RHCP), in addition to its reconfigurable filtering responses. A prototype using microstrip technology is designed, fabricated and measured to demonstrate the proposed technique. Good agreement between simulated and measured results is obtained. The measured results show that the feeding network covers a frequency range of 1.05-1.25 GHz, and the error of phase difference and amplitude imbalance are less than 5° and 0.5 dB, respectively. The resulted antenna beams can be freely switched in four polarization states with good performance.

In this communication, a novel dual-polarized (DP) epsilon-near-zero (ENZ) antenna is proposed with its operating frequencies independent to lengths for both polarizations. To obtain a DP implementation of ENZ antenna, an anti-phase epsilon-near-zero (AP-ENZ) mode is used based on a slot-fed substrate-integrated waveguide (SIW) antenna at its cutoff frequency, in which the electric field presents a sign function-like distribution, presenting a fixed operating frequency independent on length. The proposed DP length-irrelevant antenna design is composed by a cross-shaped SIW operating on two orthogonal AP-ENZ modes, which are excited by a cavity-backed cross-shaped slot with good port isolation. The SIW lengths for both polarizations can be tuned independently without disturbing the operation frequency with controllable radiation patterns. To be specific, we study two cases of different lengths where sidelobe elimination and high gain radiation are realized, respectively. To verify this design, two antenna prototypes Ant. 1 and Ant. 2 are fabricated and tested, exhibiting agreements between simulation and experiment. The proposed Ant. 1 presents no sidelobes at 2.42 GHz while Ant. 2 shows a high gain of 10.56 dBi from 2.45-2.55 GHz. The proposed design method enables antennas with a variety of radiation patterns to be designed at a fixed frequency and both symmetric and asymmetric patterns for DP antennas. It also inspires the design of a flexible antenna with unchanged operating frequency when folded in both dimensions.

In this paper, two simple structures, i.e., coupled line and T-shaped microstrip structures, are used to construct four types of quasi-reflectionless (QR) filters, including single-and two-port QR bandpass filters (BPFs) and bandstop filters (BSFs). First, the characteristics of the coupled line and T-shaped microstrip structures are analyzed in details using each two electrical parameters. Then, the single-port QR BPF and BSF are designed using duplexer architectures formed by these two simple structures. Subsequently, the two-port QR BPF and BSF are constructed through loading an additional absorption channel near the output port based on the architectures of single-port QR filters. The relations between the fractional bandwidth (FBW) of each type of QR filters and 3-dB FBWs of the two simple structures are provided, which give a guidance of the QR filter design with desired specifications. Moreover, a brief design procedure for the proposed QR filters is summarized. Finally, to validate the feasibility of the proposed approach, two proof-of-concept microstrip prototypes of the two-port QR filters are fabricated, whose simulations and measurements agree well with each other. This work will facilitate the design of QR filters with different desired specifications and simplify their design procedures.

The hydrodynamic model for Khour Al-Zubair port was introduced using the Mike 21 Flow Model FM. 2D numerical model using continuity equations and the Navier-Stokes equation to simulate hydrodynamic characteristics. Field data were collected over two different periods and on a complete tidal cycle (13 h). The model was run from October 15 to December 15, 2020, with a time step (10 sec) based on water levels and wind data. Calibration and validation of the model are evaluated based on statistical criteria (Root Mean Square Error “RMSE”, Mean Absolute Error “MAE” and correlation coefficient “R”). Depending on the values of the statistical criteria, it can be said that the results of the model were encouraging as the difference between the measured, and calculated data is not perceptible. Moreover, the results showed the behavior of tidal currents for one day of a complete cycle and the velocity of the flow in the ebb state, causing the accumulation of pollutants in the area more than in the flood state.

A dual-dc output three-phase three-level ac–dc converter is proposed for low-frequency pulsed power decoupling applications. One of the dc output is connected to the dc pulsed load, whereas the other one is used as power decoupling port and connected to the decoupling capacitor. The voltage of the power decoupling dc port can vary in a wide range to reduce the value and volume of the power decoupling capacitor. A buck/boost converter is employed to interface the power decoupling port with the dc pulsed load. A modified space vector pulsewidth modulation strategy is proposed for the ac–dc converter, based on which independent voltage and power regulation of the two dc outputs is achieved. The steady-state power is directly fed to the dc load with single power conversion stage, and the low frequency pulse power is fed to the power decoupling port. As a result, high-power quality and efficient power decoupling with reduced power conversion stages are achieved. Operation principles, modulation, and control strategies of the ac–dc converter are analyzed in detail. A prototype is built and tested to verify the effectiveness and feasibility of the proposed ac–dc converter for pulsed load.

In Wireless Power Transfer (WPT) system, applying power-relay coils is an effective method to achieve both long-distance and high-efficiency. However, the Wireless Power-Relay System (WPRS) has many variables, which will perplex the system design. An evaluation method based on black-box Z-parameter two-port model is introduced for the WPRS. This method can easily obtain the theoretical optimal efficiency and corresponding load from black-box measurement instead of acquiring all the parameters of the resonant coils. This feature can be used to compare potential performance of different WPRS. WPRS based on PCB coils are built to verify the black-box Z-parameter two-port modeling. Experiments are also carried on WPRS AC resonant tanks and WPRS DC/DC converters.

We present a novel, non-contact measurement technique for the characterization of conventional antenna parameters, including port reflection coefficient, gain and radiation pattern over a desired frequency range. Our method eliminates the need for an active measurement port connection to the antenna under test. Instead, the antenna parameters are indirectly determined by treating the test antenna input port and the port of the measurement device as a 2-port open-air fixture. The unknowns in the network representation of the open-air fixture model can be uniquely determined through a 1-port calibration process and each branch in the signal flow graph can be related to the usual antenna parameters such as input reflection coefficient, gain and radiation pattern. This approach is particularly attractive for characterizing antenna parameters when a direct connection to the antenna is either prohibitive, difficult, undesirable or expensive. On-chip antennas for mmW and THz applications, platform-integrated antennas, and body-implanted antennas are examples of the potential utility of the non-contact antenna characterization method presented here. To demonstrate the validity, scalability and overall efficacy of the proposed approach, we present the non-contact measurement of port reflection coefficient, gain and radiation pattern for various antennas of different types, with operation frequencies ranging from 60 GHz to 750 GHz.

In this letter, a design of multibeam antenna (MBA) with 2-D beam steerable capability is proposed. The proposed MBA is composed of a circular 44 butler matrix (BM) and a 24 patch antenna array. And the 24 patch antenna array consists of four 2-element subarrays uniformly arranged along E-plane. By introducing the switching diodes in the subarray and controlling the switching diodes on and off, elements of the subarray are excited through the paths with different lengths, and the beam of the subarray is steered subsequently in H-plane. The circular 44 BM is designed as the beamforming network to excite the four subarrays uniformly arranged along E-plane and steer the beam in E-plane. The proposed MBA can generate 12 beams by selecting the excitation port and controlling the on-off state of the switching diodes. To validate the performance of the proposed MBA, a prototype is fabricated and measured. By the design, the dimension of the designed MBA has reduced to 2.9 01.3 0. The designed MBA operates at 5.7 GHz, and the results show that beams of the MBA can cover the range of 36 in E-plane and 22 in H-plane, respectively.

This letter describes the wave reflection induced by the breakwater of the Port of Civitavecchia in the Tyrrhenian Sea, Italy, using a X-band wave radar. The wave radar system detected a complex structure of reflected waves that is composed of three spectral components and was generated by the complex structure of the breakwater. By applying a filter in the ω -k domain, it was possible to filter out the component of the incident waves to analyze the total component of reflected waves. Applying specific filters also made it possible to separate the spectral components of the single reflected waves. Bandpass filters were built to select each spectral component based on only the direction of the incident and reflected wave components. Starting from the separated spectral components, the reflection coefficients related to the measurement campaign were estimated and compared with the theoretical coefficients. The results confirm the potential of a radar system to resolve a complex sea state and provide a synoptic analysis of wave propagation processes over a wide measurement domain. Furthermore, this letter opens the way for new studies on the interaction between incident waves and coastal infrastructure.

In this research, a comprehensive study is performed to investigate the interaction of regular waves with the impermeable seawall of the Chabahar port. First, a MIKE 21 SW model is used to transform the deep-water wave data to the nearshore zone. Then, the interaction of waves with the seawall is simulated using a well-known numerical smoothed particle hydrodynamics model named DualSPHysics. After validating the numerical results with the experimental data, a parametric study is performed to evaluate the effects of the wave height, wave period, and the slope of the seawall on the water level fluctuations and the wave reflection coefficient. The results showed that increasing the wave height slightly decreases the reflection coefficient. Meanwhile, a direct relationship was found between the wave height and the water level fluctuations near the wall. Generally, increasing the wave period resulted in higher reflection coefficients and water level fluctuations. Both the reflection coefficient and the water level fluctuations are greatly dependent on the slope of the seawall. Steeper slopes resulted in higher reflection coefficients and lower water level fluctuations near the seawall.

This paper proposes a shared-aperture self-diplexing antenna using the composite parallel-plate waveguide (PPW). The long-straight slots (LSS) etched on the top surface of the PPW are utilized as the common radiation aperture for two operating bands. At the high frequency band, the proposed antenna, excited by the alternative-phase TE10-mode wave, operates as a leaky-wave antenna (LWA). Meanwhile, it serves as a continuous transverse stub (CTS) array antenna when excited by the TEM wave at the low frequency band. Two kinds of feeding networks are adopted to generate the alternative-phase TE10-mode wave and TEM wave, respectively. To verify the proposed method, a millimeter-wave prototype is designed, fabricated and measured. The measured results show that -10 dB fractional bandwidths are 3.42% (76.25-78.9 GHz) and 14.5% (83.2-96.2 GHz), respectively, and the port isolation is higher than 40 dB. Additionally, the peak gains are 27.1 dBi at 78.5 GHz and 25.3 dBi at 90 GHz, respectively. The proposed antenna can be used to develop compact frequency-division system without using duplexers and multi-band wireless systems.

At present, in the new hardware design work of deep learning, memristor as a non-volatile memory with computing power has become a research hotspot. The weights in the deep neural network are the floating-point number. Writing a floating-point value into a memristor will result in a loss of accuracy, and the writing process will take more time. The binarized neural network (BNN) binarizes the weights and activation values that were originally floating-point numbers to +1 and -1. This will greatly reduce the storage space consumption and time consumption of programming the resistance value of the memristor. Furthermore, this will help to simplify the programming of memristors in deep neural network circuits and speed up the inference process. This paper provides a complete solution for implementing memristive BNN. Furthermore, we improved the design of the memristor crossbar by converting the input feature map and kernel before performing the convolution operation that can ensure the sign of the input voltage of each port constant. Therefore, we do not need to determine the sign of the input voltage required by the port in advance which simplifies the process of inputting the feature map elements to each port of the crossbar in the form of voltage. At the same time, in order to ensure that the output of the current convolution layer can be directly used as the input of the next layer, we have added a corresponding processing circuit, which integrates batch-normalization and binarization operations.

A mmWave antenna with beam steering capability and a single feed is introduced. 5G systems with a single feed or a single RF chain can provide inexpensive and energy efficient solutions in applications such as the Internet of Things. The antenna consists of a half-wavelength dipole with a balun structure printed on both sides of a substrate and a parasitic pixel surface in front of the dipole. The antenna achieves beam-steering in the azimuth plane by controlling two diodes that alter the connections in the parasitic surface. Phase shifters or multiple feeds are not required to control the beam angle and therefore the antenna can support single-RF 5G operation. By introducing proper objective functions, the connections of the parasitic surface and locations of the two diodes can be optimized with the genetic algorithm. The ground plane and DC bias lines are printed on the backside of the substrate. Simulation and experimental results show that the proposed single port pattern reconfigurable antenna can operate in 26-30 GHz mmWave bands. The realized gain of 7.96 dBi and two radiation patterns with peak gains directed to 75 and 110 are verified by experiment demonstrating the feasibility of the proposed design concept.

A low-profile wideband four-corner-fed square patch antenna for 5G MIMO mobile antenna application is presented. The proposed antenna uses a single square patch to generate four uncorrelated waves over a wide band to cover 3.3-4.2 GHz (5G N77 band) with a low profile of 2.4 mm (0.03lumda at 3.75 GHz). Wideband operation is obtained by generating the half-patch TM11 mode and the quarter-patch TM1/2,1/2 mode for each port. The half-patch TM11 mode is created by embedding two diagonal linear slots in the square patch. By further placing shorting pins along the patchs two centerlines, a square two-edge-shorted quarter-patch for each port to support the quarter-patch TM1/2,1/2 mode is created, which combines with the half-patch TM11 mode to form a wide operating band. Details of the proposed antenna including the experimental results are presented.

We propose a multi-layer unit cell consisting of Minkowski fractal shaped reflector with aperture coupled phasing stubs to obtain a broad phase range for the reflectarray antenna with smaller unit cell size and inter-element spacing compared to some other studies in the literature. In the study, simulations are conducted using HFSS(TM) program with Floquet Port incidence. A unit cell with two cycles of phase range and very low reflection loss is designed. 21.9% shrinkage is achieved in patch surface area using Minkowski fractals. Subsequently, proposed unit cell is used to design and fabricate a full scale 221 element reflectarray antenna. At 10 GHz, simulation results are compared with measured data and good agreement is observed., 14 pages, 8 figures, journal

Two novel types of dual-beam switching leaky-wave antenna (LWA) arrays based on substrate-integrated waveguides (SIWs) are proposed. The two antenna arrays consist of five SIW LWAs that work on the fundamental wave and -1st spatial harmonic wave simultaneously, so the arrays can realize fixed-frequency or frequency controlled dual-beam switching properties. The LWAs in one of the arrays have the same equivalent waveguide width and different slot periods, defined as the asymmetric dual-beam switching (ADBS) array. The LWAs in the other array have the same slot period and different equivalent waveguide widths, which is defined as the hybrid dual-beam switching (HDBS) array. The open stopbands of the arrays are suppressed by a simple structure. Using voltage-driven radio frequency chip switches (CSW-RFs) to change the excitation port, the arrays can realize the function of dual-beam switching at a fixed frequency. The measured results show that the forward beam of the ADBS array can switch from 13° to 80° while its backward beam switches from -75° to -10°, and the forward beam of the HDBS array is fixed at 45° while its backward beam switches from -10° to -80° when working at 28 GHz. Furthermore, the LWAs themselves can realize frequency-controlled ADBS in each excitation state. Therefore, the proposed arrays exhibit excellent performance in flexible dual-beam switching, which can be used in millimeter-wave applications where fixed-frequency beam switching or frequency-controlled beam switching is required.

This paper presents a novel and simple method for the decoupling of a 2×2 MIMO antenna array. Two distinct radiation modes, with different patterns and polarizations, are created by novel patch element design. This new configuration enables the excitation of additional coupling paths between antennas, and ultimately the neutralization of mutual coupling. Since the two radiating modes are generated by the same patch element, the proposed MIMO antenna also features simple structure and compact size. For verification, a 2×2 MIMO antenna with center-to-center spacing of 0.475 λ0 is prototyped and characterized. Simulation and experimental results reveal that the proposed design can offer enhanced port isolation, antenna efficiency, and pattern diversity.

The new concept of relative generic subsets is introduced. It is shown that the set of controllable linear finite-dimensional port-Hamiltonian systems is a relative generic subset of the set of all linear finite-dimensional port-Hamiltonian systems. This implies that a random, continuously distributed port-Hamiltonian system is almost surely controllable.

The algorithm of parametrical synthesis of various radio devices with any quantity of cascades of type the jet two-port network a nonlinear part by criterion of maintenance of the set frequency characteristics is developed. Nonlinear parts are presented in the form of a nonlinear element and parallel either consecutive on a current or pressure of a feedback. According to this criterion systems of the algebraic equations are generated and solved. Models of optimum two-port networks in the form of mathematical expressions for definition of interrelations between elements of their classical matrix of transfer and for search of dependences of resistance of two-poles from frequency are as a result received. It is shown, that frequency characteristics of investigated radio devices from identical cascades are identical or similar to frequency characteristics of radio devices from one cascade, but with resistance of a source of a signal and the loading, changed definitely. Such schemes are named by equivalent. The comparative analysis of the theoretical results received by mathematical modelling in system MathCad, and the experimental results received by circuit simulation in systems OrCad and MicroCap, shows their satisfactory coincidence.

The algorithm of parametrical synthesis of various radio devices with any quantity of cascades of type a nonlinear part the jet two-port network by criterion of maintenance of the set frequency characteristics is developed. Nonlinear parts are presented in the form of a nonlinear element and parallel either consecutive on a current or pressure of a feedback. According to this criterion systems of the algebraic equations are generated and solved. Models of optimum two-port networks of one of cascades in the form of mathematical expressions for definition of interrelations between elements of their classical matrix of transfer and for search of dependences of resistance of two-poles from frequency are as a result received. It is spent mathematical and circuit simulation of the two-cascade amplifier. It is shown, that the increase in quantity of cascades with the optimised parametres leads to substantial growth of a working strip of frequencies. The comparative analysis of the theoretical results received by mathematical modelling in system MathCad, and the experimental results received by circuit simulation in systems OrCad and MicroCap, shows their satisfactory coincidence.

The development of devices for communication networks to transmit information has become an active and growing field of research. Multiplexer/demultiplexer (M/D) is one of the basic devices in this field. In this paper, an M/D design is introduced based on the surface plasmon resonance in optical ring resonators. The number of inputs and outputs of M/D is 3 × 1 and 1 × 3, respectively. All parameters of the structure, including radius and width of ring resonators and waveguides, have been evaluated to obtain the optimal response. Also, we used the nonlinear gold property to expand the range of M/D performance and simulated the results for intensities less than 100 MW/cm2. Selectivity in the number of inputs and outputs, controllability using several parameters, all optically, selectivity in operation frequency, nanoscale size, reconfigurability, and integrated capability are the features of this design. In our simulation, we consider transmission and reflection of light in each port based on the finite difference time domain for evaluation of results.

In this article, a novel topology generalization of a current source converter (CSC) that allows controlling of multiple single-phase ac converters independently sharing the same dc-bus, with the advantage of having a reduced number of conducting switches and a lower dc-bus current, is presented. A conventional $n$ -output/port single-phase CSC that uses the same dc-bus needs to have $n$ H-bridge converters connected in series, which means that it always has $2 n$ conducting switches. The new topology allows generating any $n$ ac output currents always having only $(n+1)$ conducting switches in a switching period. This represents $(1-{1}/{n})\!\cdot 50$ % less conduction losses when compared with the equivalent conventional multiport single-phase CSC. A scalar pulsewidth modulation to control the converters with switching optimization and its generalization is also presented. Details of topology, control strategy, and modulation are presented. Simulation and experimental results are provided to validate the theoretical approach.

Waveguides allow grating lobe free beamforming for air-coupled ultrasonic phased-arrays by reducing the effective inter-element spacing to half wavelength. Since the sound waves propagate through the waveguide ducts, additional time delays are introduced. In this work, we present analytical, numerical, and experimental methods to estimate these time delays. Afterwards, two different waveguides are compared. The first one consists of equal-length ducts, requiring a time-consuming assembly process of the ultrasonic phased-array. In contrast, the second waveguide consists of Bézier-shaped ducts of unequal lengths but a planar input port allowing fast assembly. The analytical model is based on the geometric lengths of the waveguide ducts. The numerical model relies on a transient finite element analysis. All simulations are validated in an anechoic chamber using a calibrated microphone. The analytical (7.6% deviation) and numerical (3.2% deviation) propagation time models are in good agreement with the measurements. By using the analyzed propagation times for the compensation of the unequal waveguide duct lengths, we restored the beamforming capability without significant sound pressure level (SPL) loss. This work shows the possibility of reduced transducer assembly time for waveguided air-coupled phased-arrays without a reduced SPL.

In this study, an inclusion deposition model was used to simulate the nozzle clogging process in industrial casting. The concepts of inclusion parcel and inclusion magnification factor were introduced in the model, which could be applied to an industrial-scale nozzle clogging simulation. The simulation results were verified using the results from the industry study. The results show that nozzle clogs were formed with Al-O and Al-O-Ce inclusions of diameter 5–10 μm. The nozzle clog formed initially at the nozzle bottom and was deposited on the nozzle wall during the casting process. The volume fraction of the nozzle clog in the nozzle was 52.26% at the end of the casting process. The velocity magnitude in the nozzle increased during casting. The 5 μm Al-O and Al-O-Ce inclusions cause more deposition. The number of the deposited Al-O and Al-O-Ce inclusions were similar.

This paper presents low frequency ripple power steering control strategies for a power conversion topology that comprises of a high frequency linked three port converter (HFL-TPC) and a voltage source inverter (VSI) for PV-BESS/EV applications. The proposed topology has three interfaces which can be connected with a photovoltaic (PV) port, battery energy storage systems (BESS) and/or electric vehicles (EVs) port, and a four-quadrant ac port. The proposed topology inherently exhibits double line frequency (DLF) power fluctuation that needs to be decoupled and steered away from the PV port. In this paper, we have developed and demonstrated two control strategies to deal with the DLF ripple. The first control strategy utilizes loop gain of the closed loop control system to decouple the DLF power, however a residual DLF power still exists at the ac port. To completely decouple the DLF fluctuations, an improved sequence based control strategy is proposed where the DLF voltage components are converted into positive and negative sequence components and controlled separately on their respective synchronous reference frames. To verify the practical feasibility of the proposed low frequency ripple power steering control strategies, a 40 V, 400 W HFL-TPC is built and tested. Experimental results show that the proposed ripple power steering control strategies can decouple the DLF power fluctuation and selectively steer it to the BESS/EV port as DLF power fluctuation is undesirable at the PV port. A comparative results reveal that sequence based control strategy show higher degree of DLF ripple suppression.

A simple decoupling method of using specific higher-order modes to improve the isolation of dielectric resonator antenna (DRA) elements is investigated. The higher-order modes have the feature that they can be excited by the active (source) DRA while unexcitable by means of the feeding network. As a result, the coupled fields in the passive (coupled) DRA are unable to reach the feeding port, leading to a very low mutual coupling level. When the coupled modes in the passive DRA have the same radiation characteristics with the mode that excited in the active DRA, the distortion of radiation patterns can also be avoided. This method is found effective for reducing both the E-plane and H-plane coupling. As no extra decoupling element is needed, the entire antenna system is very simple. For verification, an E-plane-coupled $1\times 2$ multiple-input-multiple-output (MIMO) DRA array has been fabricated and measured. The results show that using a proper mode, the isolation can be enhanced from about 15 to 45 dB at 5.25 GHz.

A novel dual-port phase antenna is proposed to realize 2-D scanning. The antenna consists of two monopoles on both sides and a fishbone structure in the middle. By changing the phase difference ${\Delta \varphi }$ between two monopoles, energy is coupled to the proposed structure, exciting different degrees of superposition of even and odd modes. The continuous switching from the broadside lobe to the end-fire lobe is realized, and it has the characteristic of 2-D scanning. Furthermore, to provide an in-depth insight into the 2-D scanning mechanism, two linear arrays (Array 2 and Array 3) based on the proposed antenna element and a generalized principle of pattern multiplication (GPPM) are developed. The fabricated Array 2 can offer scanning angles of 0°–73° along the $\theta $ -direction with the gain of 6.5–10.4 dBi and 90°–140° along the $\Phi $ -direction with the gain of 6.1–11.7 dBi. Its scanning coverage of 3 dB beamwidth is $0^{\circ } , $0^{\circ } . The manufactured Array 3 can scan 0°–90° along $\theta $ -direction with the gain of 8.2–11.1 dBi and 50°–90° along the $\Phi $ -direction with the gain of 6–9.36 dBi, and its 3 dB coverage of the main beam scanning is $0^{\circ } , $0^{\circ } . Consequently, the proposed antenna and GPPM can be readily extended to wide-angle scanning phased arrays.

The modeling, design, and experimental evaluation of both a 400-GHz transmitter and receiver submillimeter-wave monolithic integrated circuit (S-MMIC) is presented in this article. These S-MMICs are intended for a radar-based system in the aforementioned operating frequency. The transmitter occupies a total chip area of $750\times 2750\,{\mu {\rm m}^2}$ . It consists of a multiplier-by-four, generating the fourth-harmonic of the WR-10 input signal, which drives the integrated WR-2.2 power amplifier. The latter has an output-gate width of 128 $\mu$ m. The receiver S-MMIC, $750\times 2750\,{\mu {\rm m}^2}$ , consists of a multiplier-by-two, providing the second harmonic of the WR-10 input signal for the local-oscillator port of the subsequent integrated subharmonic mixer. The radio-frequency port of the latter, connects via a Lange coupler to a WR-2.2 low-noise amplifier (LNA). All the components included, are processed on a 35-nm ${\text{InAlAs}}/{\text{InGaAs}}$ metamorphic high-electron-mobility transistor integrated-circuit technology, utilizing two-finger transistors and thin-film microstrip lines (TFMSLs). The modeling approach of the amplifier cores and the respective design decisions taken are listed and elaborated-on in this work. Accompanying measurements and simulations of the transmitter and receiver are presented. The individual components of the aforementioned S-MMICs, are characterized and the results are included in this article. The state-of-the-art, for S-MMIC based circuits operating in the WR-2.2 band, is set by the LNA, on one side, spanning an operational 3-dB bandwidth (BW) of 310 to 475 GHz, with a peak gain of 23 dB and, on the other side, by the final transmitter design, which covers an operating range of 335 to 425 GHz with a peak-output power of 9.0 dBm and accompanying transducer gain of 11 dB. The included transmitter- and receiver-designs represent a first-time implementation in the mentioned technological process, utilizing solely TFMSLs, boasting the integration level, operating in the WR-2.2 frequency band, and setting the state of the art—to the authors’ best knowledge—for all S-MMIC based solutions in the respective frequency band, in terms of output power and gain over the operating 3-dB BW.

The research work presents the study of a heterostructured surface acoustic wave (SAW) resonator consisting of an interdigital transducer (IDT), lithium niobate (LN), and silicon (Si) substrate. In...