RLC Resonator Research Articles

Atmospheric Pressure Plasmas in Resonant Circuits

This paper attempts to give a short overview of atmospheric pressure plasmas generated in very non-uniform radiofrequency electric fields. All these forms of gas discharges have a common characteristic: they are generated based on the possibility to obtain very high voltages in resonant series RLC circuits. The paper presents both the radiofrequency generators designed in this aim and some applications of generated plasmas, especially as spectral source for analyzing of liquid and solid samples and as bacterial deactivation agent. Thus, this paper is meant for both laboratory plasma gen- erators designers and plasma spectroscopists.

APPLICATION OF RESONANT CONVERTER IN OZONE GENERATOR MODEL

Ozone is one of the favorable oxidant to use in home appliance and industry as disinfectant for food processing, food storage, odor abatement, groundwater remediation, and drinking water purification. The common and previous technical method for generating ozone uses a high voltage and low frequency. This kind of method has disadvantage of energy efficiency, size and weight. This paper proposed the use power electronics in the inverter resonant circuit to produce alternating current with high frequency. The basic RLC resonance circuit is used for early study to determine resonance frequency for inverter. As the result, the ozone chamber terminal voltage had been achieved for initiation by using resonance frequency.

THE QUANTUM FLUCTUATIONS OF MESOSCOPIC DAMPED MUTUAL INDUCTANCE COUPLED DOUBLE RESONANCE RLC CIRCUIT AT FINITE TEMPERATURE

Mesoscopic damped mutual inductance coupled double resonance RLC circuit is quantized by the method of damped harmonic oscillator quantization and linear transformation. The energy levels of this circuit are given. By thermo-field dynamics (TFD), the quantum fluctuations of the current and voltage of each loop are researched in the thermal vacuum state, thermal coherent state and thermal squeezed state. It is shown that the quantum fluctuations of the current and voltage are related not only to the circuit inherent parameter and coupled magnitude of mutual inductance, but also squeezed coefficients, squeezed angle, environmental temperature and damped resistance. Furthermore, because of environmental temperature and damped resistance, the quantum fluctuations increase with the increase of temperature and decay along with time.

Quantum fluctuations of mesoscopic damped double resonance RLC circuit with mutual capacitance–inductance coupling in thermal excitation state

Based on the scheme of damped harmonic oscillator quantization and thermo-field dynamics (TFD), the quantization of mesoscopic damped double resonance RLC circuit with mutual capacitance–inductance coupling is proposed. The quantum fluctuations of charge and current of each loop in a squeezed vacuum state are studied in the thermal excitation case. It is shown that the fluctuations not only depend on circuit inherent parameters, but also rely on excitation quantum number and squeezing parameter. Moreover, due to the finite environmental temperature and damped resistance, the fluctuations increase with the temperature rising, and decay with time.

Quantum fluctuations of mesoscopic damped mutual capacitance coupled double resonance RLC circuit in thermal excitation state

Mesoscopic damped mutual capacitance coupled double resonance circuit is quantized by the method of damped harmonic oscillator quantization. Hamiltonian is diagonalized by the method of unitary transformation. The energy spectra of this circuit are given. The quantum fluctuations of the charge and current of each loop are investigated by the method of thermofield dynamics (TFD) in thermal excitation state, thermal squeezed vacuum state, thermal vacuum state and vacuum state. It is shown that the quantum fluctuations of the charge and current are related to not only circuit inherent parameter and coupled magnitude, but also quantum number of excitation, squeezed coefficients, squeezed angle and environmental temperature. And the quantum fluctuations increase with the increase of temperature and decay with time.

The Quantum Fluctuations of Mesoscopic Damped Mutual Capacitance Coupled Double Resonance RLC Circuit in Excitation State of the Squeezed Vacuum State

Mesoscopic damped double resonance mutual capacitance coupled RLC circuit is quantized by the method of damped harmonic oscillator quantization. The Hamiltonian is diagonalized by unitary transformation. The eigenenergy spectra of this circuit are given. The quantum fluctuations of the charges and current of each loop are researched in excitation state of the squeezed vacuum state, the squeezed vacuum state and in vacuum state. It is show that, the quantum fluctuations of the charges and current are related to not only circuit inherent parameter and coupled magnitude, but also quantum number of excitation, squeezed coefficients, squeezed angle and damped resistance. And, because of damped resistance, the quantum fluctuation decay along with time.

Spurious suppression of a dual-mode bandpass filter using simple C-shaped electromagnetic bandgap cells

This article proposes a dual-mode microstrip bandpass filter (BPF) with C-shaped electromagnetic bandgap (EBG) cells etched on the ground plane for spurious suppression. The C-shaped EBG cell is modeled as a parallel RLC resonator and the equivalent circuit pa- rameters are extracted. The relationship between bandgap characteristic and dimension parameters of C-shaped EBG cell is discussed and the bandgap characteristic of C-shaped EBG cells on the filter performance is also investigated. The C-shaped EBG cells add a good stopband-re- jection mode to the second harmonics of the dual-mode microstrip BPF with suppression of over 40 dB, without affecting the center frequency

Improved Formulas for the Q of Antennas With Highly Lossy Dispersive Materials

Formulas obtained by Yaghjian and Best [ IEEE Trans. Antennas Propagat., vol. 53, pp. 1298-1324, Apr. 2005] for the quality factor (Q) of antennas containing linear passive media that is not too highly lossy and dispersive are generalized to hold in highly lossy dispersive media as well. The generalization is obtained by means of a straightforward, though ad hoc, definition of nonnegative energy densities that determine a Q which is approximately equal to twice the inverse of the matched VSWR half-power fractional impedance bandwidth of the antenna. The Q for a straight-wire antenna embedded in highly lossy dispersive media is computed using the generalized energy densities and is shown to agree closely with twice the inverse of the half-power fractional bandwidth of the antenna. Other antennas modeled by resonant RLC series and parallel circuits with the inductors and capacitors filled with lossy dispersive material further confirm the improvement in the inverse-bandwidth accuracy of the Q computed from the generalized energy densities

Signatures of quantum chaos in complex wavefunctions describing open billiards

We discuss signatures of quantum chaos in open chaotic billiards. Solutions for such a system are given by complex scattering wavefunctions ψ = u + iv when a steady current flows through the billiard. For slightly opened chaotic billiards the current distributions are simple and universal. It is remarkable that the resonant transmission through integrable billiards also gives the universal current distribution. Currents induced by the Rashba spin–orbit interaction can flow even in closed billiards. Wavefunction and current distributions for a chaotic billiard with weak and strong spin–orbit interactions have been derived and compared with numerics. Similarities with classical waves are considered. In particular we propose that the networks of electric resonance RLC circuits may be used to study wave chaos. However, being different from quantum billiards, there is a resistance from the inductors which gives rise to heat power and decoherence.

Suppression of harmonics in Wilkinson power divider using dual-band rejection by asymmetric DGS

In this paper, we present an effective technique of second and third harmonic suppression for a Wilkinson power divider by using an asymmetric spiral defected ground structure (DGS). With the proposed technique, a single asymmetric DGS provides two different resonance frequencies because of the different sizes of spiral-shaped defects on the ground plane. The transfer function of the asymmetric DGS shows signal rejection characteristics at two different resonance frequencies and the characteristics of asymmetric DGS is modeled by two parallel RLC resonance circuits in cascade. With the insertion of asymmetric spiral DGS into a quarter-wave line of the Wilkinson power divider, the second and third harmonics are suppressed simultaneously. In experimental results, 18-dB suppression for the second harmonic and 15-dB suppression for the third harmonic, respectively, are achieved. Using asymmetric DGS, the size of a quarter-wave line is reduced by 9.1% compared to that of the conventional divider without a DGS.

Electric circuit networks equivalent to chaotic quantum billiards

We consider two electric RLC resonance networks that are equivalent to quantum billiards. In a network of inductors grounded by capacitors, the eigenvalues of the quantum billiard correspond to the squared resonant frequencies. In a network of capacitors grounded by inductors, the eigenvalues of the billiard are given by the inverse of the squared resonant frequencies. In both cases, the local voltages play the role of the wave function of the quantum billiard. However, unlike for quantum billiards, there is a heat power because of the resistance of the inductors. In the equivalent chaotic billiards, we derive a distribution of the heat power which describes well the numerical statistics.

Design and fabrication of a direction sensitive MEMS shear stress sensor with high spatial and temporal resolution

Shear stress at the fluid–wall interface is one of the most frequently studied parameters in fluid dynamics. It is also a parameter of very small magnitude and calls for high resolution force sensors. Macroscopic sensors compromise dynamic bandwidth for the required high resolution and therefore cannot resolve shear stress data in space and/or time, which is very important for fundamental understanding in non-laminar fluid dynamics. We exploit the linear reduction in stiffness accompanied by cubic reduction in mass by miniaturization to design and fabricate a novel micro-electro-mechanical sensor (MEMS) for direct measurement of shear stress along and across the direction of fluid flow, with 0.01 Pa resolution and 50 kHz bandwidth along the flow. The mechanical component of the sensor is a floating beam element and capacitive comb drives supported by an in-plane torsional spring. A resonant RLC circuit, capable of sub-femtofarad capacitive sensing, is used to sense the displacement in the floating beam under shear. Fabrication of the sensor is demonstrated using silicon-on wafer (SOI) technology. The small overall size of the sensor, wide range of measurement, large bandwidth and high spatial and temporal resolution will make it useful in a wide variety of civil and military applications such as aerospace, automotive, marine and biomedical.

Analytical Studies Supplementing the Smith Chart

The study of transmission lines is basic in undergraduate electrical engineering education. In relevant courses, a key subject is the Smith chart (SC), which is a graphical device providing insight. This paper develops certain formulas that can further enhance students' understanding, including an unconventional set of conductance/susceptance transformation equations, as well as simplified versions useful for highly mismatched lines, where it is sometimes difficult to use the SC. All formulas are developed from well-known facts of transmission-line theory. SC interpretations of many of the analytical results are provided. The analytical investigations thus supplement the SC. For highly mismatched lines, the formulas bring out certain resemblances to the resonant series RLC circuit, thus providing an interesting connection to the familiar subject of ordinary circuit theory. Lastly, students can also benefit from the mathematical tools used herein; these include simple ideas of asymptotic analysis.

A Birdcage Model for the Chinese Meridian System Part I: A Channel as a Transmission Line

The concept of Qi and the concept of channel are so closely related that they must be defined and comprehended simultaneously in a coordinated fashion. Once the nature of Qi is established in terms of physics, we may be able to explain the functional role that the channels play, as well as explain other Chinese medical terminology with a language of modem science. Based on the low electrical impedance characteristics of acupoints, we propose that the meridian channel is equivalent to an electromagnetic transmission line and the Qi is the electromagnetic (EM) standing wave riding on the line, with acupoints as its nodes. The standing wave within each segment of the channel separated by acupoints is in natural oscillation thus the segment may be analyzed as a lambda/4 open circuit that behaves like a series RLC resonator. Acupuncture until De Qi is effectively equivalent to charging the capacitor Ceq of the RLC resonator in the transmission line. The mechanism of bu and xie are charging or discharging the capacitor to bring the capacititive (or inductive) behavior of the segment back to that of the resonant state. Kirlian photograph may serve as a visual observation of the EM waves on channels.

Broad-Band Dual-Frequency Microstrip Patch Antenna With Modified Sierpinski Fractal Geometry

A dual-frequency antenna based on the Sierpinski fractal with two parasitic patches to enhance the impedance bandwidth is presented. An electrical circuit model formed by RLC resonators is proposed to learn about the antenna physical behavior and to achieve the dual band operation minimizing a trial-and-error numerical/measurement proofs. The antenna has been designed using a method of moment commercial code and has been experimentally tested, obtaining two bands with a broad bandwidth and similar radiation patterns.

Periodically loaded transmission line with effective negative refractive index and negative group velocity

We present the design and implementation of a periodically loaded transmission line, which simultaneously exhibits negative refractive index (NRI) and negative group delay (and, hence, negative group velocity). This is achieved by loading the transmission line in series with capacitors and RLC resonators and in shunt with inductors. We discuss the dispersion characteristics of such a medium and identify the frequency bands of NRI and negative group delay. The structures are theoretically studied using S-parameters simulations on truncated loaded transmission lines of different lengths, and the predicted results are compared to the measured scattering parameters of such lines printed on circuit boards using coplanar waveguide technology.

Response of a simple dependent switched capacitor circuit to a pulse-train input

This paper studies a simple nonautonomous circuit consisting of an RLC resonator, a dependent switch and a periodic pulse-train input. The circuit can exhibit chaotic behavior if an equidistant pulse-train input is applied. The dynamics can be analyzed by a mapping procedure based on a one-dimensional (1-D) return map focusing on the moments when the input is applied. If the periodic pulse-train input is nonequidistant, the dynamics can be analyzed by a composite of different 1-D return maps corresponding to different pulse intervals. We show typical chaotic and periodic phenomena in this case. Using a simple test circuit, we can verify typical phenomena in the laboratory.

BSCCO SUPERCONDUCTING RESONATORS IN THE RADIOFREQUENCY DOMAIN

BSCCO/Ag-based RLC resonators have been assembled and characterized with the aim of studying the behaviour of such conductors when subjected to a radiofrequency current flow. The inductive part of the circuits is constituted by several turns of a multifilamentary BSCCO/Ag tape fabricated by the Powder-In-Tube method, and treated in such a way that the outer silver sheath is completely removed. A high-Q multilayer capacitor is directly soldered between the extremities of the superconducting tape, its value being chosen in order to tune the resonance frequency around 10 MHz. The quality factor of the assembled RLC circuits has been characterized as a function of the induced current, in order to relate the observed dissipative behaviour to the current penetration mechanism occurring in the superconducting tape.

P‐17: Low Power RLC‐Resonant Method for Driving Liquid‐Crystal Displays

AbstractIn this paper we focus on a novel method to drive the set of pixels in a LCD with lowered power dissipation. By simply adding an (surface mount) inductor to the driver IC, RLC resonant circuits can be constructed to charge and discharge the pixels periodically, hence recycling energy.

Frequency and Power Control of Induction Heater using an Adjustable Frequency Quasi-Resonant Inverter

It is to be desired that the operating frequency of a resonant inverter for induction heating is adjustable when various parts or uneven parts are treated by heating. In order to respond the demand, we reported a novel adjustable frequency quasi-resonant inverter and clarified the basic characteristics. However, the output current contained many harmonics and there was the possibility that the heat-treated depth in the uneven surface of the work did not become uniform unless the operating condition was optimum. The heat-treated depth depends on not only output frequency of the inverter but supplied power into the work coil. If the frequency and the supplied power can be controlled independently, the degree of freedom of the heat treated depth control increases. Therefor, we propose a frequency and power control method using the reported inverter. In the present method, the inverter and the induction heater are considered as a series RLC resonant circuit which includes an equivalent loss resistor and an equivalent output resistor. The input DC voltage of the inverter is so manipulated that the output power generated in the output resistor may be equal to the desired value after the operating frequency was controlled to the target value.