Parallel Resonator Research Articles

Design of Parallel Resonant Switched-Capacitor Equalizer for Series-Connected Battery Strings

The traditional pure switched-capacitor equalizer suffers from a large inrush current and low balance speed. An automatic parallel resonant switched-capacitor equalizer (PReSCE) for series-connected battery strings is proposed, which utilizes resonant switched-capacitor to eliminate the inrush current. The parallel ReSC converters not only minimizes output impedance at the low switching frequency, but delivers the excess energy to the low-voltage battery directly from the high-voltage battery in one cycle. Both of the two functions increase the balance speed. All of the switches are controlled by a pair of complementary pulsewidth modulation signals at a fixed operational frequency. Both simulation and experiment are used to verify the theoretical analysis and system feasibility of the proposed circuit. The results show that the PReSCE circuit eliminates the inrush current and increases the balance speed three times than the parallel pure switched-capacitor equalizer.

A SVPWM Method for Parallel Resonant DC Link Inverter With the Smallest Loss in the Auxiliary Commutation Circuit

In order to reduce the operating frequency and loss of the auxiliary commutation circuit (ACC) and current stress of auxiliary switches of a parallel resonant dc-link inverter (PRDCLI), this article proposes a novel space vector pulsewidth modulation (SVPWM) method. The novel SVPWM method can reduce the number of operations of the ACC to once in every PWM cycle on the premise of realizing soft switching of all switches, thereby reducing the operating frequency and loss of the ACC. At the same time, by adding the shunt dead time, the novel SVPWM method can avoid the superposition of the resonant current and load current, thereby minimizing the current stress of auxiliary switches. In addition, the novel SVPWM method can apply to any PRDCLI with the ability of variable zero voltage durations. Under the novel SVPWM method, according to the equivalent circuits of different operation modes, the operation principle, soft switching realization conditions and parameter design methods of the inverter are analyzed. Finally, a 10-kW/16-kHz prototype is built using insulated gate bipolar transistors to verify the validity of the novel SVPWM method.

0.7-1.0-GHz Switchable Dual-/Single-Band Tunable Bandpass Filter Using a Switchable J-Inverter

Cognitive radios require tunable band-switchable bandpass filters to respond to the dynamically changing operating frequencies in cognitive systems. This study presents a novel switchable dual-/single-band tunable bandpass filter using a single switchable J -inverter. The proposed filter configuration can be easily converted from a two-pole dual-passband mode to a four-pole single-passband mode using the single J-inverter with switches. This is achieved through a novel dual-band bandpass filter configuration using hybrid resonators that consist of two parallel resonators and one J-inverter. In addition, two bandwidths and two center frequencies of the dual-passband mode are designed, and a high stopband attenuation level is achieved due to a transmission zero between the two passbands. The proposed filter is built on a Duroid substrate with a dielectric constant of 3.48 and a thickness of 30 mil. The tuning of the center frequency and the passband number change are carried out using silicon varactors and PIN diodes. In the four-pole single-passband mode, a center frequency tuning of 0.75-1.08 GHz is achieved with 1-dB bandwidths of 105-158 MHz. The two-pole dual-band bandpass filter mode has a center frequency tuning of 0.69-0.9 GHz (low-band) and 0.85-1.07 GHz (high-band). It has potential for application in wideband cognitive radios.

Real-Time Abnormal-Signal Detection Under a Noisy Environment Using a Resonance Filter

In this article, we present improved short-time Fourier transform for fault detection of field coils, among the most important parts in rotating machinery. It is generally difficult to detect a fault signal of a field coil due to the low signal-to-noise ratio (SNR) associated with these signals. To solve this problem, we constructed a parallel resonance circuit using the inductance of the field coil and improved the SNR of the fault detection signal by using the bandpass filter characteristics of the resonance circuit. The transfer function curve upon parameter changes of the proposed resonance circuit is presented, and the governing equation is derived so that the resonance frequency can be calculated. We also carried out a fault detection test to verify the feasibility of the proposed method. As a result, we demonstrated that the proposed method can enhance the SNR and enable fault detection using the extracted abnormal signal. Also, it was confirmed that the proposed system responds instantaneously to an abnormal signal for fault detection. Therefore, it is proved that the methodology presented in this article is efficient for fault detection in rotating machinery.

A Method for Designing Multi-Band Rasorbers for Wideband Applications

Rasorbers with a single passband (narrow or wide) or multiple narrow passbands have been reported for stealth applications over the past few years. In this work, a method of designing the multi-band rasorber with wide passband(s) is proposed for the stealth of wideband antennas. Firstly, the method of designing multi-band FSS is proposed based on the theory of N-band resonator, in which all the passbands exhibit second-order response. Secondly, a parallel resonator combining spiral inductor and interdigital capacitor is proposed to satisfy wide passband requirements at lower frequency of the operating band. Finally, to verify the proposed method, a dual-band rasorber consisting of FSS and resistive layer is fabricated and measured. The measured results illustrate two passbands within 4.9-6 GHz (20.0%) and 8.6-9 GHz (6.3%), respectively. Three absorption bands with 48.4%, 25.7%, and 22.0% fractional bandwidths are also achieved.

Approach to Choose of Optimal Number of Turns in Planar Spiral Coils for Systems of Wireless Power Transmission

Correct choice of coil parameters for resonant circuits in inductive power transmission systems is a relevant problem, as it significantly influences the efficiency and transmitted power in the systems and provides for optimization of these parameters. This paper presents a methodology of calculation of geometrical and electrical parameters and approach to choose the optimal number of turns in planar coils used in the wireless power transmission (WPT) system with parallel resonant circuit. Formulas are derived for calculation of active resistance and inductance of the coil, normalized to the specified design parameters of the coil. Connection is made between the design and electrical parameters of the coil, which allows choosing the optimal number of turns according to different criteria and guard conditions. The examples of practical use of the chosen approach with transmitting and receiving coils of WPT system are presented. The obtained results show that efficiency and transmitted power in the system are higher when using the coils with the calculated number of turns. The proposed approach may be used in selection of optimal design of loop coils in systems with fixed frequency, and in systems, whose operational frequency depends on the parameters of the resonant circuit.

Impact of inverter digital time delay on the harmonic characteristics of grid‐connected large‐scale photovoltaic system

The digitally controlled inverter is widely applied to the photovoltaic (PV) plant, however, the effects of inverter digital time delay on the harmonic characteristic of PV system which directly influences the power quality and even the stability of the system, have not been investigated yet. This study investigates the harmonic characteristic of a grid-connected large-scale PV system based on the equivalent Norton model of the system with considering the digital time delay of the inverter. According to the system equivalent model, the series harmonic resonance circuit and the parallel harmonic resonance circuit are divided to study the impacts of digital time delay in the cases of the inverter output harmonic exist and the grid voltage harmonic exit, respectively. Then, the harmonic resonance mechanism of a grid-connected large-scale PV system is studied and the effects of digital time delay on the harmonic characteristic of system output current is quantitatively analysed by defining the harmonic magnification coefficient. It turns out that frequency and magnitude of harmonic magnification points in the grid-side current of the system are increased as the digital time delay increases. Reference to the actual 20 MWp grid-connected PV system, a simulation model is built to verify the theoretical analysis results.

Kv11 (ether-à-go-go-related gene) voltage-dependent K+ channels promote resonance and oscillation of subthreshold membrane potentials.

Key points Some ion channels are known to behave as inductors and make up the parallel resonant circuit in the plasma membrane of neurons, which enables neurons to respond to current inputs with a specific frequency (so‐called ‘resonant properties’).Here, we report that heterologous expression of mouse Kv11 voltage‐dependent K+ channels generate resonance and oscillation at depolarized membrane potentials in HEK293 cells; expressions of individual Kv11 subtypes generate resonance and oscillation with different frequency properties.Kv11.3‐expressing HEK293 cells exhibited transient conductance changes that opposed the current changes induced by voltage steps; this probably enables Kv11 channels to behave like an inductor.The resonance and oscillation of inferior olivary neurons were impaired at the resting membrane potential in Kv11.3 knockout mice.This study helps to elucidate basic ion channel properties that are crucial for the frequency responses of neurons. The plasma membranes of some neurons preferentially respond to current inputs with a specific frequency, and output as large voltage changes. This property is called resonance, and is thought to be mediated by ion channels that show inductor‐like behaviour. However, details of the candidate ion channels remain unclear. In this study, we mainly focused on the functional roles of Kv11 potassium (K+) channels, encoded by ether‐á‐go‐go‐related genes, in resonance in mouse inferior olivary (IO) neurons. We transfected HEK293 cells with long or short splice variants of Kv11.1 (Merg1a and Merg1b) or Kv11.3, and examined membrane properties using whole‐cell recording. Transfection with Kv11 channels reproduced resonance at membrane potentials depolarized from the resting state. Frequency ranges of Kv11.3‐, Kv11.1(Merg1b)‐ and Kv11.1(Merg1a)‐expressing cells were 2–6 Hz, 2–4 Hz, and 0.6–0.8 Hz, respectively. Responses of Kv11.3 currents to step voltage changes were essentially similar to those of inductor currents in the resistor–inductor–capacitor circuit. Furthermore, Kv11 transfections generated membrane potential oscillations. We also confirmed the contribution of HCN1 channels as a major mediator of resonance at more hyperpolarized potentials by transfection into HEK293 cells. The Kv11 current kinetics and properties of Kv11‐dependent resonance suggested that Kv11.3 mediated resonance in IO neurons. This finding was confirmed by the impairment of resonance and oscillation at –30 to –60 mV in Kcnh7 (Kv11.3) knockout mice. These results suggest that Kv11 channels have important roles in inducing frequency‐dependent responses in a subtype‐dependent manner from resting to depolarized membrane potentials.

Measurement Technique for Microwave Surface Resistance of Additive Manufactured Metals

Additive manufactured (AM) metals are a subject of much interest for their performance in passive microwave applications. However, limitations could arise due to artifacts, such as surface texture and/or roughness resulting from the manufacturing process. We have, therefore, adopted a parallel plate microwave resonator for the accurate measurement of the surface resistance of flat metal plates, allowing for microwave current flow in two orthogonal directions by simply exciting a different resonant mode (at 5.3 and 6.4 GHz), without the need to remove and refix the sample. The systematic and random errors associated with the measurement of surface resistance are very small, less than 1% and 0.1%, respectively. The technique is demonstrated with measurements on a range of samples of the alloys, AlSi10Mg and Ti6Al4V, manufactured by laser powder bed fusion, in addition to traditionally machined samples of bulk metal alloys of aluminum and brass. For AM samples of AlSi10Mg, we have studied the effect on the surface resistance of directional roughness features, generated by the laser raster paths, in directions transverse or parallel to microwave current flow. Importantly for passive microwave device applications, we demonstrate that these samples exhibit no systematic anisotropy of surface resistance associated with such surface features.

Low-Loss Dual-Polarized Frequency-Selective Rasorber With Graphene-Based Planar Resistor

A novel dual-polarized frequency-selective rasorber (FSR) using an omnidirectional planar resistor based on graphene flake is presented in this article. The FSR exhibits a low-loss transmission window above an absorption band. It consists of a lossy layer and a lossless bandpass frequency-selective surface (FSS). In the lossy layer, a central symmetric graphene-metal hybrid structure is formed by connecting four metal strip-based resonant circuits with a square graphene flake. A low insertion loss transmission band is obtained by removing the resistance out of the parallel resonant circuits. Moreover, equivalent circuits are utilized to demonstrate the working mechanism. The proposed FSR exhibits a good absorption performance from 8.15 to 13.8 GHz, and a low insertion loss of 0.15 dB obtained at 16 GHz. Finally, a prototype FSR is fabricated and good agreement between the simulated and the measured results is obtained. The FSR has further advantages of avoiding the process of welding multiple lumped resistors per unit, thereby greatly reducing the number of lumped components and improving the planar integration of the structure.

Impact of Frequency Mismatch on the Quality Factor of Large Arrays of X-Cut Lithium Niobate MEMS Resonators

This paper investigates the impact of resonant frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ) mismatch on the quality factor (Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">as</sub> ) of large arrays of X-cut Lithium Niobate (LN) Laterally Vibrating Resonators (LVRs) operating around 50 MHz and 400 MHz. The statistical distributions of key device parameters, including resonant frequency, quality factor (Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ), electromechanical coupling (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), and static capacitance (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ), are collected from replicas of identical resonators. A Monte Carlo approach is later implemented to simulate the impact of statistical variability on the quality factor of arrays of resonators. By including the effect of interconnects series resistance on the arrays, an excellent agreement between experimental and simulated Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">as</sub> is achieved, demonstrating that frequency mismatch is the major mechanism of quality factor degradation in arrays of parallel resonators. The experimental validation of the model confirms that it can be used as a predictive tool to establish the frequency tolerance requirements in order to attain high Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">as</sub> in arrays.

Multi‐resonators, microwave microfluidic sensor for liquid characterization

AbstractIn this paper, a new type of microwave microfluidic sensor is presented, using three separate half wave microstrip resonators with a common junction. The sensor comprises three parallel resonators with resonant frequencies of 2.5, 3.5, and 4.5 GHz. This sensor exhibits all the usual advantages of microwave resonant methods for dielectric liquid characterization, such as high precision, accuracy, and sensitivity, but here also over a wideband of frequencies. The resonators have common input and output ports. The sensor was tested using several types of liquids, including water, methanol, ethanol, and chloroform, and experimental results are in excellent agreement with the simulation results.

CMOS series-shunt single-pole double-throw transmit/receive switch and low noise amplifier design for internet of things based radio frequency identification devices

The incompatibility between current RFID standards has led to the need for universal and Wi-Fi compatible RFID for IoT applications. Such a universal RFID requires an SPDT and an LNA to direct and amplify the received raw signal by the antenna. The SPDT suffers from low isolation, high insertion loss and low power handling capacity whereas the LNA suffers from bulky die area, lesser Q factor, limited tuning flexibility etc. because of passive inductor usage in current generation of devices. In this research, nano-CMOS inductorless SPDT and LNA designs are proposed. The SPDT adopts a series-shunt topology along with parallel resonant circuits and resistive body floating in order to achieve improved insertion loss and isolation performance whereas the LNA design is implemented with the gyrator concept in which the frequency selective tank circuit is formed with an active inductor accompanied by the buffer circuits. The post-layout simulation results, utilizing 90nm CMOS process of cadence virtuoso, exhibit that our SPDT design accomplishes 0.83dB insertion loss, a 45.3dB isolation, and a 11.3dBm power-handling capacity whereas the LNA achieves a peak gain of 33dB, bandwidth of 30MHz and NF of 6.6dB at 2.45GHz center frequency. Both the SPDT and LNA have very compact layout which are 0.003mm 2 and 127.7 μm 2 , respectively. Such SPDT and LNA design will boost the widespread adaptation of Wi-Fi-compatible IoT RFID technology.

Resonant Frequency and Load Voltage in Voltage-Source Type Wireless Power Transfer Circuits using Series and Parallel Resonant Capacitors

Resonant Frequency and Load Voltage in Voltage-Source Type Wireless Power Transfer Circuits using Series and Parallel Resonant Capacitors

Lumped element balanced multi‐band bandstop filter for ultra high frequency applications

An ultra-compact multi-band balanced (differential) bandstop filter (BSF) topology with all lumped elements has been introduced for the first time in this study. The proposed filter is a four-port structure where each symmetrical bisection is a series cascade of K N -band cells. Each N -band cell comprises of N parallel resonant circuits connected to the same node, through capacitors. K series-coupled N -band filter sections in the symmetrical bisection exhibit a K th order N -band BSF response in differential mode (DM) whereas common mode (CM) signal is minimally affected and maintains a high CM rejection ratio (CMRR). The advantages associated with this engineered structure can be summarised as follows: (i) it can be extrapolated to realise an arbitrary number of DM stopbands; (ii) it does not need any additional component in the symmetry plane to suppress the CM noise; and (iii) it occupies a very small area. For demonstration, a second-order dual-band differential BSF with resonant frequencies 1.15 and 1.36 GHz is designed and fabricated. It offers a rejection level of about 25 dB for each DM stopband and maintains a CMRR value of about 25 dB for both bands. Moreover, it covers an area of only 0.003, where is the guided wavelength at the centre frequency between the two bands.

LC resonant circuits based matching networks for continuous mode MMIC power amplifiers

AbstractThis article presents a practical design methodology to construct output matching networks for broadband continuous mode monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). Unlike conventional harmonic manipulation approaches, combinations of parallel and series LC resonant circuits are utilized to build the matching networks as it can generate frequency‐dependent components and locate the varying impedance of continuous mode. With a proper design, the impedance variation in frequency domain can be mapped to the frequency response of the matching network at the fundamental frequency and the second harmonic simultaneously. Matching network design procedures are demonstrated and results show that the frequency response of the network has very good approximation with the desired continuous mode conditions. A prototype PA is implemented on 0.25‐μm gallium nitride (GaN) MMIC process, and tested with both continuous‐wave and modulated signals. Measurement results show 50.82% maximum drain efficiency and 8.5 dB gain can be achieved across the operation bandwidth of 5.4 to 6.4 GHz.

Tracking Control of Nanopositioning Stages Using Parallel Resonant Controllers for High-Speed Nonraster Sequential Scanning

The resonant controller (RC), as a promising candidate for high-speed nonraster nanopositioning applications, can track the sinusoidal reference with zero steady-state error. This article presents a controller composed of several RCs in parallel for tracking nonraster sequential scanning trajectories. The selection for each RC in the parallel array is based on two considerations: one is the spectrum of the reference signal and the other is the harmonics caused by the nonlinearities of the nanopositioning stage. The performance of RC is highly dependent on the accurate placement of the resonant poles, but unfortunately, many existing digital implementation methods could cause a deviation of the resonant poles from their initial locations. To address this problem, a modified Tustin (MTus) method is proposed in this article to implement the controller with better accuracy. Furthermore, the fractional-order (FO) calculus is introduced to improve the transient performance of the RCs. To validate the proposed methods, a comprehensive examination of several types of the nonraster sequential scanning trajectories with a wide frequency range has been carried out on a nanopositioning stage. The results have been compared with other methods, showing that the tracking errors are reduced significantly under the controller implemented by the MTus method especially in high-frequency conditions and that the application of the FO calculus reduces the settling time of the controller by more than 30% in most cases. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The demand for high-speed atomic force microscope (AFM) increases rapidly. However, the commonly used raster trajectory limits the achievable scan speed of the AFM. An effective way to improve the scanning and imaging speed of the AFM is the application of the sequential nonraster scanning methods. The trajectories of sequential nonraster scanning patterns mainly composed of few sinusoid signals with different frequencies. Therefore, the resonant controller (RC) is introduced in this article as it is capable to track the sinusoidal reference with zero steady-state error. Several RCs are selected first based on the spectrum analysis of the reference and the consideration of the harmonics caused by the system nonlinearities, and then, they are connected in parallel to form the controller for precise tracking of the reference. In order to realize the digital implementation of the designed controller, a modified Tustin discretization method is proposed, which ensures the accurate resonant pole placement of the RC and thus maintains the tracking performance of the RC. In addition, the fractional-order (FO) calculus is introduced to speed up the convergence of the designed controller while preserving the tracking accuracy, and this parallel-structure FO RC (PSFORC) design can be implemented to other systems that require high-speed and high-accuracy tracking of the periodic signals.

An inline pseudoelliptic self‐packaging substrate integrated suspended line filter with mixed electric and magnetic coupling

A novel compact and self-packaging inline pseudoelliptic filter is proposed. The proposed filter exploits controllable mixed electric and magnetic coupling using substrate integrated suspended line (SISL) technology. Based on a synchronously tuned coupled resonator circuit with parallel LC resonant tank and admittance inverters, general formulas for extracting electric and magnetic coupling coefficients are derived. Meanwhile, a basic mixed coupled SISL resonator pair is investigated and a systematic design procedure of a second-order mixed coupled SISL filter is also given. Two prototypes of the second-order filter with one transmission zero (TZ) at either upper or lower stopband are designed, which is corresponding to either magnetic or electric coupling dominant case. Furthermore, for asynchronously tuned coupled resonator cases, an inline third-order pseudoelliptic SISL filter characterized by symmetric TZs is designed, fabricated, and measured for validation. The simulated and measured results show a good agreement with the synthesized ones.

Spectrally broadband electro-optic modulation with nanoelectromechanical string resonators.

In this paper, we present a shutter-based electro-optical modulator made of two parallel nanoelectromechanical silicon nitride string resonators. These strings are covered with electrically connected gold electrodes and actuated either by Lorentz or electrostatic forces. The in-plane string vibrations modulate the width of the gap between the strings. The gold electrodes on both sides of the gap act as a mobile mirror that modulate the laser light that is focused in the middle of this gap. These electro-optical modulators can achieve an optical modulation depth of almost 100% for a driving voltage lower than 1 mV at a frequency of 314 kHz. The frequency range is determined by the string resonance frequency, which can take values of the order of a few hundred kilohertz to several megahertz. The strings are driven in the strongly nonlinear regime, which allows a frequency tuning of several kilohertz without significant effect on the optical modulation depth.

Inverse design of all-dielectric parallel-plane mirror optical resonator

Inverse-design algorithms can be used to design compact and high-performance complex photonic structures. In this study, we propose the design of an all-dielectric optical resonator based on the concept of the parallel mirror resonator by using the objective-first inverse design algorithm. Light is strongly confined using a predefined objective function that creates symmetric mirror regions acting as reflective layers for the fundamental transverse-electric polarization mode. Thanks to the flexibility of the algorithm, segments of the cavity and dielectric mirror are designed in a simulation region by choosing a cavity of an appropriate length. A time-domain analysis of the proposed structure was carried out using the two-dimensional finite-difference time-domain method. The proposed structure has a configuration with a footprint of 13.394 × 0.592 μm2. The algorithm generates an inverse-designed structure to obtain a resonance peak at the target wavelength without any intuitive scanning of the complete parameter space. As a result, the first-order mode is strongly localized in the region of the cavity for the defined design wavelength. Moreover, the application of the inversely designed resonator as refractive index sensor is examined to show that the proposed structure has the potential for use in integrated photonic devices. Thus, the objective-first inverse design algorithm is promising for use in the design of a variety of photonic structures.