Series Resonance Research Articles

Series resonance effects of a variable inductor termination on the nonpowered electrode in capacitively coupled plasmas

The effect of LC series resonance on the voltage of a nonpowered electrode in a capacitively coupled plasma is investigated by connecting a variable inductor to the nonpowered electrode. Two distinct LC series resonances are observed while varying the reactance of the variable inductor. The first resonance occurs between an inductor and a vacuum variable capacitor, thereby resulting in the voltage of the nonpowered electrode approaching zero. The reactance between the inductor and the vacuum variable capacitor is minimized at this resonance, thereby enabling the nonpowered electrode voltage to remain close to 0 V even with increased applied RF power. The second resonance is a series resonance between the variable inductor and the nonpowered electrode sheath, leading to a maximization of the nonpowered electrode voltage. The reactance between the variable inductor and the nonpowered electrode sheath is minimized at this resonance. As the applied RF power increases under the second resonance condition, the voltage of the nonpowered electrode increases, thereby resulting in a significant increase in the maximum electron density by approximately 35%. This increase in the electron density at the second resonance can be attributed to enhanced stochastic heating due to the sharp increase in the sheath voltage.

A New Doherty Combiner with Wide Bandwidth for Magnitude and Phase Balance Compensation

This paper proposes a novel Doherty combiner that uses a series and parallel resonant circuit for wideband. Unlike conventional combiners, the aim of the proposed combiners is to extend bandwidth for not only the magnitude bandwidth, but also phase balance by employing series and parallel resonant circuits at the output impedance of the peaking amplifier. Considering the load impedance of the peaking amplifier, the Doherty combiners were analyzed in the theory of this study by deriving the series and parallel resonant circuit values. The output phase balances are determined for the targeted bandwidth to achieve uniform phase balance in the proposed combiner I using a series resonator. For better magnitude bandwidth, the slope of reflection coefficient (Γ) at port 3 in the combiner II using series resonator was derived using the derivative of Γ with respect to ω. Experimental results show that the proposed combiner I has 63.5% magnitude fractional bandwidth (FBW) and 118% FBW with the phase balance at ±2.5°. The proposed combiner II also has 85% magnitude FBW and 118% FBW with the phase balance at ±2.5°.

Identification and mitigation of conducting package losses for quantum superconducting devices

Low-loss superconducting rf devices are required when used for quantum computation. Here, we present a series of measurements and simulations showing that conducting losses in the packaging of our superconducting resonator devices affect the maximum achievable internal quality factors (Qi) for a series of thin-film Al quarter-wave resonators with fundamental resonant frequencies varying between 4.9 and 5.8 GHz. By utilizing resonators with different widths and gaps, different volumes of the stored electromagnetic energy were sampled, thus affecting Qi. When the backside of the sapphire substrate of the resonator device is adhered to a Cu package with a conducting silver glue, a monotonic decrease in the maximum achievable Qi is found as the electromagnetic sampling volume is increased. This is a result of induced currents in large surface resistance regions and dissipation underneath the substrate. By placing a hole underneath the substrate and using superconducting material for the package, we decrease the Ohmic losses and increase the maximum Qi for the larger size resonators.

Global simulation of plasma series resonance effect in radio frequency capacitively coupled Ar/O2 plasma

Radio frequency capacitively coupled plasmas (RF CCPs) play a pivotal role in various applications in etching and deposition processes on a microscopic scale in semiconductor manufacturing. In the discharge process, the plasma series resonance (PSR) effect is easily observed in electrically asymmetric and geometrically asymmetric discharges, which could largely influence the power absorption, ionization rate, etc. In this work, the PSR effect arising from geometrically and electrically asymmetric discharge in argon–oxygen mixture gas is mainly investigated by using a plasma equivalent circuit model coupled with a global model. At relatively low pressures, as Ar content (α) increases, the inductance of the bulk is weakened, which leads to a more obvious PSR phenomenon and a higher resonance frequency (ω psr). When the Ar content is fixed, varying the pressure and gap distance could also have different effects on the PSR effect. With the increase of the pressure, the PSR frequency shifts towards the higher order, but in the case of much higher pressure, the PSR oscillation would be strongly damped by frequent electron–neutral collisions. With the increase of the gap distance, the PSR frequency becomes lower. In addition, electrically asymmetric waveforms applied to a geometrically asymmetric chamber may weaken or enhance the asymmetry of the discharge and regulate the PSR effect. In this work, the Ar/O2 electronegative mixture gas is introduced in a capacitive discharge to study the PSR effect under geometric asymmetry effect and electrical asymmetry effect, which can provide necessary guidance in laboratory research and current applications.

VWM-DCRNN: A Method of Combining Signal Processing With Deep Learning for Fault Diagnosis in Single-Phase PWM Rectifier

Based on variational mode decomposition and dual model of convolutional recurrent neural network (VMD-DCRNN), a novel diagnosis method is proposed to discover the faults of IGBTs, diodes and series resonant circuit in single-phase pulse width modulation (PWM) AC-DC rectifier, an important part of traction power supply system of high-speed railway. By virtue of the combination of signal processing and deep learning schemes, the multi-scale feature information for fault diagnosis is extracted by regarding the input current of the rectifier and the voltage of dc side as the original signal. More clearly, VMD is adopted to decompose the original signal to a series of intrinsic mode function components (IMFs). Then, the submodel of current is designed to detect the fault types of IGBTs and diodes. Meanwhile, the submodel of voltage is established to identify the fault types of series resonant circuit. These IMFs are fed into DCRNN consisting of the two submodels for training and testing. Finally, the features extracted from the two submodels are integrated and converted to label space to complete fault diagnosis. Experimental results show that the proposed VMD-DCRNN algorithm is superior to the single-channel models, reaching 96.27%.

Automatic segmentation of the female pelvic floor muscles on MRI for pelvic floor function assessment.

Pelvic organ prolapse (POP) is a pelvic floor dysfunction disease which affects females. The volume of pelvic floor muscle, especially the levator ani muscle (LAM), is an important indicator of pelvic floor function. However, muscle volume measurements depend on manual segmentation, which is clinically time-consuming. In this work, we present an efficient automatic segmentation model of pelvic floor muscles with magnetic resonance imaging (MRI) based on DenseUnet, to achieve muscle volume calculation and provide a reference for the assessment of pelvic floor function. A total of 49 female pelvic floor magnetic resonance (MR) series were retrospectively enrolled from the First Affiliated Hospital of Army Military Medical University between 2013 and 2021, including 21 normal participants and 28 patients with stage 1-4 POP. The LAM, internal obturator muscle (IOM), and external anal sphincter (EAS) were manually segmented. An improved DenseUnet was proposed for automatic segmentation of these 3 muscles. The Dice similarity coefficient (DSC), Hausdorff distance (HD), and average symmetrical surface distance (ASSD) were used to evaluate segmentation results. The segmentation performance of the improved DenseUnet was compared with those of standard DenseUnet, ResUnet, Unet++, and Unet. The improved DenseUnet showed a good performance. The average DSC and standard deviation of the LAM, IOM, and EAS was 0.758±0.151, 0.716±0.173, and 0.810±0.147, respectively. The average HD was 22.41, 19.00, and 36.01 mm, respectively; and the average ASSD was 3.66, 3.80, and 5.23 mm, respectively. The average DSC and standard deviation of the normal group and POP group was 0.779±0.166 and 0.757±0.154, respectively. There was no significant difference between the muscle volume of the improved DenseUnet and manual segmentation (all P values >0.05). The average total segmentation time for 1 case was 10.18 s on our setup, which is much lower than the manual segmentation time of 45 minutes. The improved DenseUnet segments the pelvic floor muscles in MRI quickly and efficiently, with good precision and faster speed than those of manual segmentation. This can assist doctors in quickly segmenting pelvic floor muscles, calculating muscle volume, and further evaluating pelvic floor function.

선박용 연료전지 시스템을 위한 대전류 전력변환기 개발

Several basic components of the fuel cell system for ships include a fuel cell stack, a power conversion system, a battery, and a control device. Polymer electrolyte membrane fuel cell(PEMFC) is considered the most important component in this system as it has a variety of advantages such as high-power density, fast response speed, and low operating temperature. However, a stable, high-efficiency boost converter must be manufactured to utilize it as a power source for ships due to several drawbacks like low voltage and a wide range of fluctuation and high currents. This paper aims to study the design and implementation of a high-current power conversion system utilizing an insulated resonance converter for the fuel cell system for ships. The proposed power converter in this study consists of a two-stage conversion structure, which incorporates a two-phase interleaved boost converter and a series resonance converter(SRC). The performance of the structure is verified by testing a 30 kW class unit module manufactured.

Refinement of the environmental and chronological context of the archeological site El Harhoura 2 (Rabat, Morocco) using paleoclimatic simulations

Abstract. This study illustrates the strong potential of combining paleoenvironmental reconstructions and paleoclimate modeling to refine the paleoenvironmental and chronological context of archeological and paleontological sites. We focus on the El Harhoura 2 cave (EH), an archeological site located on the North Atlantic coast of Morocco that covers a period from the Late Pleistocene to the mid-Holocene. In several stratigraphic layers, inconsistencies are observed between species presence and isotope-based inferences used to reconstruct paleoenvironmental conditions. The stratigraphy of EH also shows chronological inconsistencies in older layers between age estimated by optically stimulated luminescence (OSL) and a combination of uranium series and electron spin resonance methods (combined US–ESR). To infer global paleoclimate variation over the EH sequence in the area, we produced an ensemble of atmosphere-only simulations using the LMDZOR6A model, using boundary conditions and forcings from pre-existing climate simulations performed with the IPSL Earth system climate model to match the different key periods. We conducted a consistency approach between paleoclimatic simulations and paleoenvironmental inferences available from EH. Our main results show that the climate sequence based on combined US–ESR ages is more consistent with paleoenvironmental inferences than the climate sequence based on OSL ages. We also evidence that isotope-based inferences are more consistent with the paleoclimate sequence than species-based inferences. These results highlight the difference in scale between the information provided by each of these paleoenvironmental proxies. Our approach is transferable to other sites due to the increasing number of available paleoclimate simulations.

Dual-Functional Energy Harvesting and Low-Frequency Vibration Attenuation: Electromagnetic Resonant Shunt Series Quasi-Zero-Stiffness Isolators

In recent times, there has been a significant focus on electromagnetic resonant shunt damping (ERSD) and quasi-zero-stiffness vibration isolators (QZS VI) as prominent solutions for vibration mitigation or energy harvesting. In this paper, an innovative retrofittable model is proposed for dual-functional energy harvesting and low-frequency vibration attenuation by combining the ERSD and two-stage quasi-zero-stiffness vibration isolator (TQZS VI). The viscous dissipative element between the TQZS VI upper and lower layers is implemented using an electromagnetic shunt transducer that is connected in parallel with a resonant RLC (resistor–inductor–capacitor) circuit. Firstly, the mathematical model of the electromagnetic resonant shunt series quasi-zero-stiffness isolator (ERS-TQZS VI) is developed. Then, the magnitude-frequency response equations of the ERS-TQZS VI system are approximately solved using the harmonic balance method (HBM) in combination with the pseudo-arc-length method (PLM). The analytical approach is validated using numerical simulations. Moreover, the force transmissibility and output power of the ERS-TQZS VI are defined, and detailed parametric analysis for energy harvesting and low-frequency vibration attenuation is performed to assess the critical design parameters that result in optimal performance of the ERS-TQZS VI. The results demonstrate that the ERS-TQZS VI exhibits a significant reduction in resonance peaks of low-frequency vibration while simultaneously enabling effective vibration energy harvesting.

Coplanar Stripline Single Pole Single Throw Switch

Coplanar stripline (CPS) series-connected spurline resonators are terminated with diodes, which can have a voltage applied to them, creating either a short circuit or open circuit. By connecting two spurline resonators in series separated by a quarter-wavelength transmission line, and when the diodes are reverse biased, the total circuit passes the RF power unimpeded. When the diodes are forward-biased, the circuit is a bandstop filter. This creates a CPS RF series switch with an insertion loss of 0.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm$</tex-math> </inline-formula> 0.1 dB, a reflection coefficient of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 30 dB, and an isolation of 20 dB. The switch was simulated, fabricated, and measured for both single-element and two-element configurations.

High-Frequency Modeling of the High-Voltage Electric Drive System for Conducted EMI Simulation in Electric Vehicles

To address the problems of the existing motor behavioral models, which are not suitable for time-domain simulation, difficult to parameterize, cannot capture multiple resonances, and neglect the low-impedance antiresonance phenomenon, a motor behavioral modeling approach based on series and parallel resonances in common-mode and differential-mode impedance is first proposed. Compared with the measured results and existing models, the presented motor model indicates significant improvements in terms of accuracy, universality, and convenience. Secondly, a high-frequency model of the high-voltage electric drive system (EDS) is developed based on the cable model, the inverter model, and the novel motor behavioral model, which considers various parasitics at high frequencies. Comparison with experimental results depicts that the novel EDS model can effectively predict system-level conducted electromagnetic interference up to 100 MHz with an error of 5 dB or less at most frequencies. Finally, compared with the existing frequency modeling technique, it further demonstrates that the proposed EDS modeling method displays significant superiority in respect of improving prediction precision and applicable frequency range.

A Novel High-Voltage-Gain Quasi-Resonant DC–DC Converter With Active-Clamp and Switched-Capacitor Techniques

We propose an isolated high-voltage-gain quasi-resonant dc-dc converter with a bi-functional circuit for the renewable energy applications. The proposed converter adopts an interleaved connection in the primary side, reducing input current ripple, and includes the bi-functional circuit operating as the switched-capacitor cells and two active-clamped circuits simultaneously. The converter realizes high voltage conversion ratio without using extreme duty ratio, and the voltage spike due to the leakage inductance of the isolation transformer is clamped. In addition, an output voltage doubler in the secondary side comprises a series resonant circuit and then obtains zero current switching (ZCS) turn-off of rectifying diodes; the diode reverse recovery problems are also alleviated. A 320W laboratory prototype that operates at input of 26 V-34 V and output of 400 V is fabricated to verify the effectiveness of the proposed converter.

Scale-invariant resonance characteristics in magnetized capacitive radio frequency plasmas

Resonance mechanisms have been found to be essential for the generation of high-density rf plasmas at low pressures, in which electrons can be continuously accelerated through multiple interactions with the oscillating rf sheaths. In this work, we report the scale-invariant resonance mechanisms, such as bounce resonance heating and plasma series resonance, in low-pressure capacitive rf plasmas in the presence of an external magnetic field. The generation conditions for the resonance mechanisms are determined via fully kinetic simulations. It is found that the resonance dynamical properties of single-frequency plasmas (e.g., a double-peak electron density vs magnetic field curve) can be exactly replicated at different scales when three combined control parameters, i.e., the reduced gap distance pd (pressure × distance), reduced driving frequency f/p (frequency divided by pressure), and reduced magnetic field B/p (magnetic field divided by pressure), are kept constant. The similarity relations for the electron density and electron power absorption in magnetized rf plasmas are numerically confirmed. Furthermore, the similarity and scale-invariant resonance characteristics are elucidated through the scaling of the Boltzmann equation with collisional terms for weakly ionized rf plasmas with a magnetic field, which is proven to be theoretically exact.

Voltage balance control for a hybrid dual-bridge series resonance converter with wide soft-switching region and reduced tank current

Voltage balance control for a hybrid dual-bridge series resonance converter with wide soft-switching region and reduced tank current

Wideband Circularly Polarized Reflectarray Antenna Using Rotational Symmetrical Crossed Dipoles

A wideband circularly polarized (CP) reflectarray (RA) antenna using rotational symmetrical crossed dipoles is presented. This is the first time investigating coupled crossed dipoles as the unit cell for wideband reflection bandwidth in the CP RA design. Equivalent circuit analysis shows that when a CP wave impinges on the designed unit cell, two series resonances and two parallel resonances are simultaneously excited on the crossed dipoles. Owing to these four different resonances, the CP reflection bandwidth is greatly improved and elaborately adjusted by controlling the coupling between the crossed dipoles. The CP reflection bandwidth ratio of the unit cell is enhanced up to 2:1 for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S_x</i> <-15 dB with a thin thickness of 0.12λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Based on this unit cell, a wideband -20° collimated CP RA antenna with a circular aperture of 316 unit cells was designed, fabricated, and measured for final performance verification. The measured results show that a wide CP bandwidth of 7.6-15.9 GHz is achieved with the axial ratio <3 dB. In addition, the measured 3dB gain bandwidth is better than 43.7% with the peak realized gain of 26.3 dBic and the maximum aperture efficiency of 58.3%.

An equivalent circuit for magnetoelectric composites operating in a longitudinal mode resonance: BAW-actuated mechanical antenna

It brings new design perspectives to study mechanical antenna in the view of circuit rather than the electromagnetic field. In this paper, an equivalent circuit of bulk acoustic wave (BAW) antenna is constructed by using constitutive relation of magnetoelectric composites and Newton’s governing equation. Based on this circuit, series and parallel resonant frequencies of two phases for BAW antenna are simulated in advanced design system (ADS) and magnetoelectric coupling coefficient is calculated. The results show that the electromechanical coupling coefficient is about 6%, the magnetomechanical coupling coefficient is about 86%, and the magnetoelectric coupling coefficient is about 5.2% under the existing material system (AlN and FeGaB). The magnetoelectric voltage gain is derived based on Kirchhoff’s Current Law, which contributes to studying the influence of the two phases thickness ratio on the performance of BAW antenna. The results show that BAW antenna has the optimal energy coupling and conversion when the thickness ratio of the two phases is 1:1. The input and the output impedances of BAW antenna are calculated by T-parameter matrix, which are perfectly matched with the results in ADS simulation. Relevant experiments have been carried out by preparing the magnetoelectric antenna based on PZT and Terfenol-D materials to verify the universality of the model.

Glycan Stability and Flexibility: Thermodynamic and Kinetic Characterization of Nonconventional Hydrogen Bonding in Lewis Antigens.

We provide evidence for CH-based nonconventional hydrogen bonds (H-bonds) for 10 Lewis antigens and two of their rhamnose analogues. We also characterize the thermodynamics and kinetics of the H-bonds in these molecules and present a plausible explanation for the presence of nonconventional H-bonds in Lewis antigens. Using an alternative method to simultaneously fit a series of temperature-dependent fast exchange nuclear magnetic resonance (NMR) spectra, we determined that the H-bonded conformation is favored by ∼1 kcal/mol over the non-H-bonded conformation. Additionally, a comparison of temperature-dependent 13C linewidths in various Lewis antigens and the two rhamnose analogues reveals H-bonds between the carbonyl oxygen of the N-acetyl group of N-acetylglucosamine and the OH2 group of galactose/fucose. The data presented herein provide insight into the contribution of nonconventional H-bonding to molecular structure and could therefore be used for the rational design of therapeutics.

Adaptation of Inductive Power Transfer to Small Household Appliances That Can Operate on Induction Heating Cooktops: Wireless Electric Kettle

In this paper, an inductive power transfer (IPT) system without compensation elements is presented for small house appliances. The proposed system’s transmitter side is an independent induction heating cooktop. IPT can be achieved when the kettle with the receiving coils is placed on the transmitter coil. The coils are designed with a high coupling coefficient. The magnetic system model consisting of aligned transmitter and receiver coils is created in the Maxwell program. In the created model, the analysis depends on the air gap and frequency, which are the variables that affect the wireless power transfer. The electronic circuit simulation uses the coil model to examine the system’s dynamic behavior. The design of the transmitter/receiver coils of the IPT system is made with a cylindrical coil with a diameter of 145 mm, taking into account that it is compatible with the dimensions of the existing kettle and induction heating cooktops coil. A half-bridge series resonant converter circuit is used to adjust the power transferred to the load. To verify the simulation results and test the designed system, an experimental circuit using a 2200 W kettle is carried out. In the experiments, the air gap between the coils is kept constant at 7 mm, and measurements are taken for different powers. Experimental results confirm the magnetic model and simulation results. As a result, wireless power transfer is realized in a wide range without loss of performance in the kettle. System efficiency is greater than the 90% specified in the Ki cordless kitchen standard, and the harmonic currents drawn from the mains are lower than the values determined by the IEC 61000-3-2 standard.

Rydberg Excitons and Trions in Monolayer MoTe2.

Monolayer transition metal dichalcogenide (TMDC) semiconductors exhibit strong excitonic optical resonances, which serve as a microscopic, noninvasive probe into their fundamental properties. Like the hydrogen atom, such excitons can exhibit an entire Rydberg series of resonances. Excitons have been extensively studied in most TMDCs (MoS2, MoSe2, WS2, and WSe2), but detailed exploration of excitonic phenomena has been lacking in the important TMDC material molybdenum ditelluride (MoTe2). Here, we report an experimental investigation of excitonic luminescence properties of monolayer MoTe2 to understand the excitonic Rydberg series, up to 3s. We report a significant modification of emission energies with temperature (4 to 300 K), thereby quantifying the exciton-phonon coupling. Furthermore, we observe a strongly gate-tunable exciton-trion interplay for all the Rydberg states governed mainly by free-carrier screening, Pauli blocking, and band gap renormalization in agreement with the results of first-principles GW plus Bethe-Salpeter equation approach calculations. Our results help bring monolayer MoTe2 closer to its potential applications in near-infrared optoelectronics and photonic devices.

Topology Assessment for Dual-Band Filters Based on Acoustic Wave Resonators

This work assesses three different approaches to the design of dual-band filters with single-ended input and output based on acoustic wave (AW) technology together with the filter synthesis methodology behind each structure. First, the straightforward option, already on the market, is to connect two standalone ladder filters in parallel. This work provides a synthesis view to this option and also describes its strong limitations regarding achievable isolation. Nonetheless, departing from the classical ladder, an innovative topology is proposed in which series and shunt resonators of different sub-bands are concatenated forming a double-ladder topology. Although this latter structure is able to achieve better isolation levels, this work describes the particular constraints arising from this innovative solution in terms of response and technology requirements. Finally, the conventional ladder structure with a single signal path is proposed as a strong candidate to accommodate dual-band filtering responses for the first time. All three structures are discussed from a filter synthesis perspective, describing the particular constraints behind each topology. Also, each structure is reviewed and compared in technological terms to highlight its main advantages and disadvantages.