Parallel Resonator Research Articles

Current Sharing for a Multiphase Inverter Based on Coupled External Parallel Resonant Branches for Wireless Power Transfer System

Current Sharing for a Multiphase Inverter Based on Coupled External Parallel Resonant Branches for Wireless Power Transfer System

Reconfigurable bandpass filter with flexible tuning of both center frequency and bandwidth

This paper proposes a novel reconfigurable filter that can flexibly tune both the center frequency and bandwidth simultaneously. This reconfigurable filter consists of a filter network with Chebyshev properties and a parallel resonator. These two structures are symmetrical and can be analyzed using the odd-even mode analysis method for the filtering network. With the addition of a tuning factor, the Chebyshev filter network provides a shift in passband and coupling coefficients that can be adjusted to maintain a stable bandwidth; the parallel resonators will produce adjustable transmission zeros on either side of the passband, providing good out-of-band rejection when adjusting the bandwidth and center frequency. By using the transformation of the resonant frequency of two filtering networks, filters of different orders can also be achieved. This reconfigurable filter can achieve continuous bandwidth and center frequency adjustment and can maintain a constant absolute bandwidth during the center frequency adjustment process, with flexible tuning methods. Through simulation and experiments, it has been proven that this reconfigurable filter has a tunable frequency coverage range of 0.4GHz to 2GHz, with a large tunable range.

A simple, flexible technique for RF cavity wake-field calculations

It is typical in the accelerator field to model machine components, especially RF cavities, as parallel RLC resonators. To properly model wake-fields, knowledge of the time-domain voltage resulting from beam excitation is often necessary. While analytical and quasi-analytical expressions are available to accomplish this for common bunch distributions such as the Gaussian, analogous results for less standard distributions can be difficult or computationally-taxing to obtain using direct methods, which opens the door for the development of a more generalized technique. In this paper, a formulation is created that allows for the simple computation of the time-domain voltage waveform of an RLC resonator. The formulation uses the Cauchy Residue Theorem to extract the convolution result from the Fourier Domain, and if current distribution Fourier Transform has no poles, knowledge of its value is only required at one specific evaluation point. This greatly simplifies the computation of the time domain voltage for a large amount of bunch distributions both common and uncommon. Accuracy considerations for this technique and the approximation of accelerator components as RLC resonators are also discussed, resulting the development of a figure of merit for quantifying the robustness of this type of approximation.

Advancing frequency fine-tuning: a theoretical approach to a novel metamaterial-inspired Bi-layer resonator

This study presents a novel adjustable device designed for precise frequency tuning within the S-band of the microwave spectra. In addition to the geometrical design and dielectric behavior of the resonator, this study identifies an influential governing factor that affects the resonant frequency. The proposed method utilizes a bi-layer split ring resonator configuration implemented on a FR4 epoxy substrate with a dielectric constant of 4.4. The substrate is coated with a 35 μm- thick layer of copper and patterned as split ring resonator. Frequency tuning was achieved by spatially separating the two parallel split ring resonators in increments of 800 μm. This innovative approach allows for a shift in the resonant frequency range from 2.36 GHz to 2.61 GHz, covering the desired frequencies in the S-band for applications such as biomedical and wireless communications. This study demonstrates that the alteration in the frequency domain is dependent on the distance between the two layers of split ring resonators. Compared to existing frequency tuning mechanisms, this adjustable bi-layer split ring resonator offers numerous advantages including simplicity, cost-effectiveness, and high sensitivity. The research employs a combination of finite-element simulations and theoretical analysis to validate the findings.

A Parallel Resonant DC Link Inverter With Low Current Stress on Main Switch

A Parallel Resonant DC Link Inverter With Low Current Stress on Main Switch

Equivalent circuit of a planar microwave liquid sensor based on metamaterial complementary split ring resonator

Abstract In the present work, a study of a metamaterial complementary split ring resonator (CSRR) microwave planar sensor for dielectric liquid characterization is carried out using HFSS software. The design consists in a CSRR-loaded two ports rectangular patch microstrip-fed grounded planar structure. The investigated liquid sample is put in a capillary glass tube lying parallel to the surface of the sensor. The liquid test tube is deposited horizontally parallel to the surface of the planar sensor. The advantage of the design lies on the fact that it allows different orientations and multiple size possibilities of the test tube. This makes it possible to explore different resonant frequencies in the 2.1 GHz frequency band. Moreover, an optimization study is carried out to achieve a high sensitivity and a high-quality factor of the proposed sensor. To better understand the operation and to further verify the feasibility of the equivalent circuit, a parallel RLC resonant circuit is used to obtain the desired Z parameter responses Z 11, Z 22, Z 21. A T-shaped electrical model of the proposed sensing structure is established using Advanced Design System (ADS) software. This latter constitutes one of the principal novelties of this work, which has never been addressed so far.

The effect of electrical parameters of eddy current sensor on metal film thickness measurement performance and the optimization method.

Eddy current sensors have been widely used in the field of micro- and nano-measurements. The detection circuit is a key part of eddy current sensors. In particular, the electrical parameters in the signal conversion circuit have an important effect on the measurement performance. It is necessary to study the effect of the electrical parameters on the measurement performance and propose an optimization method. In this study, a simulation model of the eddy current sensor is established by coupling a magnetic field and a circuit field. The circuits include the LC parallel resonance, the AC bridge, and three combination circuits of the LC resonant and AC bridge. The output voltage variation with the thickness of copper film is calculated, and the effect of the electrical parameters on sensitivity Ki is obtained. In the LC parallel resonant circuit, it' is revealed that K1 is maximum when the parallel capacitance CP is equal to the resonant capacitance C0. An optimization method of adjusting resistance RS in different thickness intervals is proposed. In the AC bridge circuit, it' is revealed that there exists an optimal RS, which makes K2 maximum. In three combination circuits, K3, K4, and K5 are the maximum when the capacitances (C1, C2, and C3) reach the resonant capacitance C0. In addition, the sensitivity of each combination circuit is improved compared with that of the AC bridge. The relevant analysis results are further verified by a series of experiments. According to the calculation results and the experimental analysis, the optimization method for electrical parameters is further proposed.

Research on Multiple-Band Terahertz Metamaterial Absorbers Having Narrow Discrete Spacing Enabled by Multiple Parallel Metallic Strip Resonators

Research on Multiple-Band Terahertz Metamaterial Absorbers Having Narrow Discrete Spacing Enabled by Multiple Parallel Metallic Strip Resonators

Discrete-Time Frequency-Domain Disturbance Observer to Mitigate Harmonic Current in PMSM Drives and the Implementation With Reduced Delay

The disturbance observer (DOB) can be employed in electric drives to improve disturbance rejection. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -filter of classical frequency-domain DOBs to attenuate multiple harmonic disturbances is high-order and faces issues including discretization, numerical precision, and frequency adaption, thus its realization in variable-speed drives would be challengeable. This paper proposes a discrete-time multi-frequency DOB (MFDOB) to address these issues. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> -filter of the proposed design is constructed with an integrator and several parallel resonators in a closed-loop structure. It uses a single parameter per harmonic to control the disturbance rejection bandwidth and the performance is guaranteed under various fundamental frequencies. The impact of the computation delay on the MFDOB-based current control is studied, and the system with less computation delay exhibits a higher stability margin and a wider range of low sensitivity. To eliminate the computation delay, a real-time pulse-width-modulation (PWM) update scheme is also developed for the DOB-based two-degree-of-freedom (2DOF) controller. The proposed method is evaluated on a laboratory permanent magnet synchronous machine platform.

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°.

Research on an Adaptive Compound Control Strategy of a Hybrid Compensation System

This paper investigates the parallel harmonic resonance problem for hybrid compensation systems, consisting of active power filters and thyristor-switched capacitors, and proposes an adaptive composite control strategy for solving the parallel harmonic resonance problem that may arise in practical applications of hybrid compensation systems. In practice, a hybrid compensation system can effectively solve harmonic and reactive power problems, but the equivalent reactance of the thyristor-switched capacitor and the supply line may form a parallel resonant circuit, which may generate parallel harmonic resonance when excited by a harmonic source at the non-linear load side, affecting the quality and stable operation of the system. The adaptive composite control strategy employs a second-order generalized integrator-frequency-locked loop (SOGI-FLL) to extract the harmonic voltage at the point of common coupling (PCC) and generate an adaptive damping current command using an adaptive algorithm, which adaptively adjusts the parameters of the resonance suppression controller through harmonic content limitation. Matlab/Simulink simulations show that the method effectively achieves harmonic resonance suppression of the power supply system under complex operating conditions, thus ensuring the stable operation and power quality of the power supply system. Therefore, the proposed control strategy is feasible and effective.

Design Consideration of ZVS Single-Ended Parallel Resonant DC-DC Converter, Based on Application of Optimization Techniques

The paper presents the design of a single-ended transistor zero-voltage switch (ZVS) parallel resonant DC-DC converter. Due to the use of a resonant inverter in the structure of the DC-DC converter, it is characterized by high efficiency and improved performance. On the other hand, due to the specifics of the power circuit operation, in the work, it is proposed to find the values of some of the elements of the circuit of the electronic converter to be carried out based on the application of optimization. To solve this task, various tools available in Matlab/Simulink have been applied, as well as author’s programs specially developed for the purpose. The use of a hybrid method for the design of power electronic converters, which combines analytical and optimization approaches, is justified in cases where there is no adequate design procedure. With the increase in the complexity of the power topologies and their possible modes of operation, difficulties arise related to their design such as: assumptions and limitations in conducting the analysis and the corresponding methodologies based on this analysis; high order of the differential equations composing the mathematical models; need for highly qualified specialists in the field of design. The proposed approach does not negate the classical design methods based only on analytical ratios determined by analysis of power circuits, but complements and develops them with innovative ones based on the application of computational mathematics and information and communication technologies.

Compact and Efficient Dual-Band Rectifier Using Modified T-Section Matching Network

In this letter, a compact and efficient dual-band rectifier for radio frequency (RF) energy harvesting is presented. The proposed design utilizes a modified T-section comprising a parallel resonance circuit combination of LC in the shunt arm, which plays a key role in obtaining the resultant dual-band rectifier. The shunt arm provides a shift of the high-frequency point in the clockwise direction on the impedance trace (Smith chart) while maintaining an insignificant shift at the lower frequency. The proposed design is verified through theoretical and simulation studies for different Schottky diodes. The circuit is optimized and fabricated to compensate for undesired parasitic effects and achieve the required rectifier performance. For validation, a dual-band rectifier working at 1.4 and 2.45 GHz is fabricated. The measured results show that with a 3.02 k <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $</tex-math> </inline-formula> load, the maximum efficiencies of the rectifier achieve 65.0% and 57.0% at 1.4 and 2.45 GHz, respectively with 0 dBm input power.

Research on LC parallel resonant circuit

This paper introduces the resonant condition of LC parallel resonant circuit and the resonant condition under ideal condition. Through the combination of calculation and simulation, the analysis of the actual resonant circuit, which makes the waveform sine is affected, the distortion of the parameters. Combined with the full-response resonant circuit with sinusoidal excitation source of the same frequency, the parameters that affect the optimal resonant state when the circuit is at a fixed resonant frequency are derived. Finally, the above theory is verified by experiment, and the characteristics of LC parallel resonant circuit are obtained.

A Wide Tuning Range Dual-Core Quad-Mode Orthogonal-Coupled VCO With Concurrently Dual-Output Using Parallel 8-Shaped Resonator

This article presents a dual-core quad-mode orthogonal-coupled wide frequency tuning range voltage-controlled oscillator (VCO) using mode control switches to realize the even/odd mode selection. Each core of the VCO adopts a parallel 8-shaped coil structure to avoid the influence of the other orthogonal-coupled one. Together with capacitor banks and varactors, the combination of orthogonal-coupled VCO cores demonstrates an extremely wide frequency tuning range on the basis of the existing range expanding from the dual-mode. The proposed VCO can be classified into two cases with different applications. One is that only one oscillation frequency is required; thus, four modes together show a wide frequency range. The other is that two different oscillation signals can be provided at the same time. The VCO has a measured tuning range of 8.3–21.7 GHz for the combination of low-and high-band cores. It consumes 4–6 mW with a measured phase noise 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> 127 dBc/Hz at a 10-MHz offset from a carrier of 9.6 GHz, and the FoM and FoM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm{T}}$</tex-math> </inline-formula> are <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> 179 and <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> 199 dBc/Hz, respectively. The VCO is designed and implemented in the 65-nm complementary metal-oxide-semiconductor (CMOS) technology with a die area of 0.4 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> .

Power Generation Control Method of Fixed-power Parallel Resonant PMSG System for Series Hybrid Vehicle

Power Generation Control Method of Fixed-power Parallel Resonant PMSG System for Series Hybrid Vehicle

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.

Ternary RCS reduction metasurface based on a parallel resonance circuit

Ternary RCS reduction metasurface based on a parallel resonance circuit

Bidirectional Gain Enhancement of Folded Dipole Antenna Using Midstrips Array

A novel low-profile method to improve the bidirectional gain of a dual-element folded dipole antenna (DFDA) is presented. The proposed technique employs surface current distribution conditioning using integrated parasitic elements while preserving the radiators. We introduce a middle layer consisting of a 1-D array of metal strips embedded between the upper and lower surfaces of the dipole, called midstrips. The midstrips are designed as parallel resonators and play the key role of current polarizing of the dipole currents. At the presence of the midstrips, the cross currents on the dipole surface are polarized out of phase and cancel each other, improving radiation-polarization purity consequently. The co- components are changed from a distributed form to a triple current form, which leads to the excitation of a new resonance. The geometric-progression-based array factor is extracted to model the gain enhancement mathematically. Two DFDA prototypes with and without midstrips are fabricated with identical thickness ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.014\lambda _{0}$ </tex-math></inline-formula> at 2.7 GHz) and 10 dB-S11 bandwidth of over 18.5%, which shows a bidirectional-gain enhancement of more than 2.9 dB and an efficiency of over 84% at the presence of the midstrips.

Low-Profile Higher-Order Narrowband Bandpass Miniaturized-Element Frequency-Selective Surface

We present a low-profile miniaturized-element frequency-selective surface (MEFSS) with narrowband, second-order bandpass response. The miniaturized-element unit cell comprises a capacitively loaded parallel LC unit cell resulting in a narrowband bandpass response. A higher-order filtering response is obtained by implementing five metallic layers FSS formed by two layers of parallel LC resonators with an inductive impedance inverter layer in between them. The proposed design offers a very thin profile and an insensitive frequency response to the polarization of the incident electromagnetic wave. A design procedure is developed for the proposed FSS structure based on an equivalent circuit model analysis. Using this model, a prototype of MEFSS with the second-order bandpass response at 3.34 GHz and a fractional bandwidth of 3.7% is designed, realized, and characterized experimentally. The measurement results of the FSS verify the effectiveness of the FSS design procedure and the stability of its frequency response up to 60° oblique incidence angles.