Loop Resonator Research Articles

Nonlinear dynamics of MEMS resonator in PLL-AGC self-oscillation loop

Nonlinear dynamics of MEMS resonator in PLL-AGC self-oscillation loop

Design of Microstrip Dual-Mode Wideband Bandpass Filter with Controlled Center Frequency and Bandwidth Using Bandstop Filter Topology

ABSTRACT This paper discusses a new method for designing a microstrip dual-mode, sharp skirt, wideband bandpass filter with controlled center frequency and bandwidth from bandstop filter topology. A meander closed loop resonator with directly connected orthogonal feed lines provides a Bandstop filter (BSF) with reduced size. A pair of L-shaped open stubs introduced along the diagonal axis D-D1 realizes a wide passband within the rejection band (0.93–4.13 GHz) of the bandstop filter with sharp stopbands on either side of the passband. Furthermore, the effect of L-shaped open stubs susceptance on passband edges is demonstrated. A quarter wavelength stepped impedance shunt stub (SISS) connected at is proposed to achieve additional transmission zeros in the upper and lower rejection bands to improve the sharpness of filter response. Both center frequency and bandwidth of the proposed filter are controlled by the impedance ratio (R) of the SISS element. The proposed filter is simulated using ADS, fabricated and measured using Vector Network Analyzer (VNA). A good agreement is achieved between simulated and measured results.

An Analytical Approach for the Estimation of the Far-Field Reduction Obtained by Placing Closed Conductor Loops in Proximity to a Chip

A recent study proposed a technique to mitigate the far-field emission and susceptibility of printed circuit boards (PCBs) with the use of a suspended metal loop. This article provides, with the help of the small-loop theory, a methodology to analytically predict and further estimate the electromagnetic field (EMF) distribution and level at very large distances from the emitting PCB (as is the case for CISPR radiated emission measurements up to 10 m test distances), where full-wave simulations and experiments are very challenging (if not impossible as a practical matter). The suitability of the methodology was assessed for various radiator size and frequency as well as the loop radius and configuration with respect to the emitting PCB. As proof-of-concept, full-wave simulations and measurements have been performed. The root-mean-squared error (RMSE) was considered as the measure of the accuracy between the analytical and full-wave numerical results. It has been demonstrated that, whatever the loop radius and/or position with respect to the radiating integrated circuit (IC), the proposed methodology can approximate the far-field EMFs with low RMSE values. Moreover, as far as the emitting IC is concerned, independently of its size and radiating frequency (except near the loop resonance), a good precision was achieved with the analytical model compared to the full-wave numerical analysis. Furthermore, the approach was found to be effective not only on-axis but also off-axis of the suspended conductor loop. Apart from the required computational power for full-wave simulations, thanks to the proposed methodology, it is possible to significantly reduce the huge difference in computational time for numerical ( $\gg$ 30 min, depending on the distance) and analytical ( $ few seconds, independently of distance) analyses.

Investigation of supersonic twin-jet coupling using spatial linear stability analysis

Abstract

A Cuk Converter and Resonant LLC Converter Based E-Bike Charger for Wide Output Voltage Variations

In this article, an e-bike charging solution for two wheelers, is presented. This e-bike charger is realized by a Cuk converter followed by a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter with an improved power quality (PQ) input current indices. The pulsewidth modulated Cuk converter is operated in discontinuous conduction mode of its output side inductor, which leads to a voltage follower approach for input current shaping. Thus, the control loop is greatly simplified as it consists of a single voltage loop. The e-bike battery charging algorithm is implemented in variable frequency controlled HB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter followed by a diode rectification at its output stage. Furthermore, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{550}\;\text{W}$</tex-math></inline-formula> , constant current/constant voltage charger with a maximum current rating of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{10}\;\text{A}$</tex-math></inline-formula> is developed to charge a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$20AH$</tex-math></inline-formula> e-bike battery. A variable dc link reference voltage estimator is presented, which varies the dc link voltage and extends the output voltage range for charging e-bike battery of varying voltage rating from 42– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{80}\;\text{V}$</tex-math></inline-formula> . Moreover, a resonant frequency optimizer loop is also proposed, which reduces the turn-off losses during charging a deeply discharged battery. The behavior of this charger is exhaustively analyzed under steady state and transient conditions and the PQ at the input, is found to comply the international standard of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$IEC-61\,000-3-2$</tex-math></inline-formula> .

Dual‐Band Filtering Dielectric Antenna Using High‐Quality‐Factor Y3Al5O12 Transparent Dielectric Ceramic

The Y3Al5O12 transparent dielectric ceramic is of permittivity εr ≈10.53 and Q × f ≈ 95219 GHz (Q = quality factor = 1/tanδ and f = 7.37 GHz), which is excellent to be applied for the dielectric resonator antenna (DRA). A dual‐band filtering DRA (FDRA) is proposed to verify the special dielectric properties of Y3Al5O12 transparent dielectric ceramic. The FDRA is designed by seamlessly integrating a dual‐band DRA based on rectangular Y3Al5O12 transparent ceramic with a quadruple‐mode stub‐loaded loop resonator (SLLR). The DRA operates at the and modes excited by a common coupling slot. The SLLR serves as a feeding network, whereas the DRA works as a dual‐mode resonator as well as the radiating element. The reflection coefficient, realized gain, and the radiation pattern of the dual‐band FDRA are examined. It is observed that the proposed FDRA operates at 3.42 and 5.28 GHz with impedance bandwidths of 5.8% and 4.0%, respectively, which are used for the fifth‐generation (5G) network and applications. Good dual‐band filtering performance is achieved while realizing radiation efficiency above 84.1% and 85.4% at two bands.

Compact high‐selectivity high‐temperature superconducting wideband bandpass filter using triple‐mode stub‐loaded loop resonator

A triangle triple-mode stub-loaded loop resonator (SLLR) is proposed in this letter and used for wideband filter design. Also, this SLLR can produce multiple transmission zeros for high-selectivity bandpass filter (BPF) design without adding extra circuit unit. To verify the unique characteristics of the proposed SLLR, a compact wideband BPF is designed and fabricated using high-temperature superconducting YBCO thin films on a MgO substrate. Furthermore, a novel meander structure is introduced to realize compact size and strong input/output coupling design. The measured results show that the 3-dB fractional bandwidth is of 50.6% (2.55-4.28 GHz), and the selectivity factor of the passband is 0.87 with a maximum insertion loss of 0.07 dB, indicating good agreement with the theoretical expectation.

Uncooled CMOS 2.5THz detector comprising a metamaterial absorber loaded with resistors and a PTAT sensor

Terahertz (THz) detectors have shown a multitude of important prospects in the fields of THz technology. This paper presents an innovative metamaterial (MM) absorber combined with a temperature sensor, leading to a new type of room-temperature CMOS THz thermal detector. The innovative MM absorber implemented in the 55 nm CMOS process is presented across the THz frequency range for the first time. It is based on a loop resonator loaded with four polysilicon resistors for higher responsivity. The theoretical analysis, multi-physics simulations and experimental validations of the detector are presented in detail. Experimental results of detectors loaded with polysilicon resistors and without polysilicon resistors are obtained at 2.5 THz for comparison. The proposed detector loaded with resistors shows a DC responsivity of 57.1 V/W and a noise equivalent power (NEP) of 0.21 μW/√Hz. The detector without resistors achieves a DC responsivity of 20.18 V/W with a NEP of 0.59 μW/√Hz at 30 Hz. The presented novel detector could be easily scaled to array formats, showing significant potentials toward room-temperature, compact, inexpensive, easy-integration and high-yield THz detection systems.

Performance enhanced folded multiband MIMO antenna for mobile terminals

A novel compact folded antenna for 4G and 5G application in handheld devices such as mobile phones is proposed in this paper. The radiator comprises of meandered monopole, dual L-Shaped monopole, square radiator, asymmetric U-Shaped monopole, Closed Loop resonator, F-Shaped stub for providing the desired operating bands. The size reduction is achieved using folding technique. The antenna can be easily folded and integrated at the top right corner within the metal casing of the devices. Folded structure with the foot print of 50 × 6 mm2 covers multiband operation such as LTE700 / GSM850 / 900 / LTE 2300 / WLAN 2400 / LTE 2500 / Wi-MAX 3500 / Wi-Fi 5200/5800 MHz corresponds to 2G/3G/4G/5G services. To provide high data rate and throughput, MIMO concept is exploited with the folded radiators at the top left and right corners of the printed circuit board. The realized gain and radiation efficiency of the proposed antenna are 2.45/4.12/4.54/5.03/6.58 dBi and 82/85/87/89/90% respectively at the design frequencies 0.7/2.3/2.5/3.5/5.8 GHz. The SAR values of the folded antenna is computed and found to be less than 1.6 W/Kg.

Listening to NFC at higher harmonic frequencies

The widespread use of the NFC technology (Near Field Communication) arouses interest to various security aspects. There are known examples of information exchange with card at a distance greater than standard 5-10 cm. It is also interesting to use signals of higher harmonics, which potentially may be radiated in the form of electromagnetic waves, rather than exists as a magnetic field of scattering. In this work, the radiation of third harmonic by card of standard ISO 14443-3А with the fundamental frequency 13.56 MHZ for various excitation modes using the RFID-RC522 reader, smartphone Sony Xperia Z5 Premium, and continuous 10% amplitude modulated 13.56 MHz signal from generator with the subcarrier of imitated smart card response 847.5 kHz was investigated. The card response at third harmonic was simulated in circuit analysis software. Both simulation and experiment proved, that the third harmonic with its side frequencies 40,68 ± 0,8475 MHz have the highest level after the fundamental. To receive the third harmonic signal, the resonant loop antenna in the form of ring vibrator loaded on capacitor was used. This allows the sizes of the received system to be reduced, but the problem of complex field structure in the near-field zone remains. Due to narrow bandwidth of the receiver antenna, the registration of card response signal was complicated. The experiments with three methods of signal generation proved, that third-harmonic signal is registered at the distance more than 1.5m, which may pose a threat for contactless smart-cards transactions security. At the same time, the influence of high level of noise at such a distance may cause difficulties to decode the short-duration signals, which requires further study.

Wearable Planar Magnetoinductive Waveguide: A Low-Loss Approach to WBANs

We introduce an alternative approach for wireless body area networks (WBANs) that rely on wearable planar magnetoinductive waveguides (MIWs) placed upon the body to reduce loss by 50–60 dB versus the conventional state of the art. Compared to our recently reported MIW WBANs that rely on axial rather than planar electrically small resonant loops, this approach: 1) overcomes the inherent constraints of anatomical geometry; 2) provides uniform WBAN implementations across the entire human body or different human bodies; 3) allows for frequency scalability over a wide frequency range; 4) exhibits more degrees of freedom for design optimization; and 5) provides significantly better performance (28.92 dB loss improvement for an example 5-loop design). In this work, we discuss the operating principle and validate the idea via a theoretical dispersion model. Numerical full-wave simulations are then presented and further validated via <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vitro</i> experimental results on a canonical torso model. Design optimization is subsequently performed for performance (loss and bandwidth), accompanied by a reasoning analysis based on the theoretical dispersion model. Specific absorption rate (SAR) studies confirm electromagnetic safety, while frequency scalability and tolerance to anatomical curvature further highlight its potential. Overall, the reported approach significantly advances the state of the art and shows promise for low-loss WBANs of the future.

JET ILA full array and polychromatic operation

The JET ILA is an Ion Cyclotron Resonance Heating (ICRH) antenna composed of four resonant double loops (RDLs) arranged in a 2 toroidal by 2 poloidal compact array. It has been operated in a range of frequencies from 29 to 51 MHz, but mostly on half array. Some full array pulses were achieved but without all control loops implemented.All control algorithms (first and second stage matching, toroidal and poloidal phasing, totalling 22 feedback loops) have now been implemented and recently allowed to operate the full array at 33 MHz and 42 MHz up to 4 MW. It also allowed for the first time to perform a poloidal phase scan of the antenna at 37 MHz, with dipole toroidal phasing.Although full array operation has mostly proven reliable at 33 MHz, it has proven unstable at 42 MHz in several occasions due to the high level of mutual coupling between the different RDLs inherent to a compact array. To decouple the control of the top and bottom halves, first tests were successfully performed with polychromatic – or dual frequency – operation of the ILA (operation at 2 different frequencies around a central frequency).

Synthesis approach to design a compact printed monopole filtenna for 2.4 GHz Wi‐Fi application

This communication presents a compact low cost filtenna (35 mm × 30 mm) operating in 2.31 to 2.49 GHz spectrum for possible applications pertaining to 2.4 GHz Wi-Fi standards 802.11b, 802.11g, and 802.11n. Initially, two microstrip square open loop resonators are designed to serve as band-pass filters with resonant frequency of 2.4 GHz. Adapting the synthesis approach, the second resonator is replaced by inverted L-shaped monopole antenna designed at 2.4 GHz. The antenna is integrated to filter through coupled line admittance inverter to form a compact module with near zero insertion loss within the proposed operating frequency band, filtenna possess uniform omnidirectional radiation pattern in H-plane and monopole pattern in E-plane, steep skirt at both edges, 7.5% fractional bandwidth, good return loss and low cross polarization characteristics. The simulated design is validated by measurements of parameters of prototype fabricated on FR4 substrate, slight acceptable discrepancy is experienced which can be attributed to fabrication tolerances and variation in material characteristics.

Analisa Elemen Multiarms Resonator Open Loop Pada Band-Pass Filter Mikrostrip Yang Bekerja Di Frekuensi EHF

The use of bandpass filters is commonly used but the use of specifications varies depending on needs, in this case the microstrip bandpass filter is expected to observe the multiarms characteristics of the open loop resonator on the performance of the bandpass filter for EHF frequencies. The design of this microstrip bandpass filter uses a multiarms open loop resonator design where at the beginning of the simulation stage uses only 1 arm with patch width, arm spacing, feeder line width and patch length based on trial and error. The final simulation results are obtained with a connector distance of 2 mm and a distance of 1 mm between arms with a value of S11 = -13.8 dB and S21 = -2.8 dB at a frequency of 30.8 GHz based on the simulation results. The filter has been successfully fabricated but cannot be measured because the frequency is too high and the measuring instrument cannot measure the frequency

Multi-Inverter Phase-Shifted Control for IPT With Overlapped Transmitters

A high-power inductive power transfer system with overlapped transmitters driven by a multi-inverter topology is proposed in this article. Each inverter drives an independent primary coil to transfer energy to the common secondary coil. A phase-shifted control strategy at inverter-level is proposed to regulate the output of the system. A dynamic model based on virtual resonant loop is proposed to describe the system with the phase-shift angle and the output voltage as the input and output variables, respectively. With the introduction of virtual resonant loop, n practical resonant loops at the primary side can be expressed by two equations, which greatly reduce the scale and order of the model. A PI controller is developed to evaluate the system regulating performance. A laboratory prototype driven by three inverters connected in parallel was built to verify the theoretical analysis. Experiments have shown that the setting times were within 13 ms under load resistance and reference disturbances, which verified the validity of the model and the controller.

Design and Validification of Trilateral Censored Resonator Structure with Patch Antenna Intended for WLAN Purposes

Background: Recently the vast improvement in wireless communications has occurred that satisfies the IEEE standard Wireless LAN (WLAN) ideograms in the range of 2.4~2.5 GHz. WLAN is usually used in the wireless applications and devices such as tab, PCs, and iPhones. Among the various techniques and proposed structure for better execution, Imitation Magnetic Electrode (IME), Electromagnetic Band Cavity (EBC), divided Loop Resonator (VLR), Photonic Group Cavity (PGC), etc. have been used. Objective: This research explores the effect of a proposed Completing Equilateral Trilateral Censored Separated Roar Resonator (CETCSRR) antenna at 2.4 GHz for better coverage in WLAN application. Methods: The dual ETCSRR and single CETCSRR structure has been cut from the top of the patch. The performance has been study in terms of twelve rotational TCSRR pair, number of TCSRR, size of TCSRR and distance between DTCSRRs structures. Finally proof the RL design and its equivalent circuit by using CST and ADS software. Results: Simulated results for dual CETCSRR at resonant frequency 2.441 GHz show RL of - 36.084 dB and gain of 7.75 dB has been obtained. The antenna split gap stores, charges, and works as a capacitor that accelerates gain, radiation pattern with radio frequency Tx and Rx to use as a WLAN scheme. Conclusion: The ETCSRR designed antenna reverberates between 2.43GHz to 2.45 GHz ISM bands along with the alignment and addition of ETCSRR cell. The proposed design is helpful for frequency harmonic explanation as well as predictable upgrade in bandwidth and impression of gain and directivity.

Frequency-Selective Planar Coil Architecture Modeling for WPT Access Control

In this paper, an approach to access control in wireless power transfer (WPT) systems via frequency-selective architecture is proposed. We perform modeling of planar square loop resonance behavior in GHz range using Ansys HFSS®. Power transfer efficiency is found from the accepted power and radiated power. Using a multi-coil design, where the transmitter and receiver switch between coils of different resonance frequencies in sync, can provide for effective access control.

A Self-Powered Hybrid SSHI Circuit with a Wide Operation Range for Piezoelectric Energy Harvesting.

This paper presents a piezoelectric (PE) energy harvesting circuit, which integrates a Synchronized Switch Harvesting on Inductor (SSHI) circuit and a diode bridge rectifier. A typical SSHI circuit cannot transfer the power from a PE cantilever into the load when the rectified voltage is higher than a certain voltage. The proposed circuit addresses this problem. It uses the two resonant loops for flipping the capacitor voltage and energy transfer in each half cycle. One resonant loop is typically used for the parallel SSHI scheme, and the other for the series SSHI scheme. The hybrid SSHI circuit using the two resonant loops enables the proposed circuit’s output voltage to no longer be limited. The circuit is self-powered and has the capability of starting without the help of an external battery. Eleven simple discrete components prototyped the circuit. The experimental results show that, compared with the full-bridge (FB) circuit, the amount of power harvested from a PE cantilever and the Voltage Range of Interest (VRI) of the proposed circuit is increased by 2.9 times and by 4.4 times, respectively. A power conversion efficiency of 83.2% is achieved.

Power Decoupling Control for V2G/G2V/PV2G Operation Modes in Single-Phase PV/Battery Hybrid Energy System With Low DC-Link Capacitance

Three-port intelligent conversion systems, interfacing photovoltaic (PV) arrays and electric vehicles (EVs), with an electrical grid, are a promising flexible infrastructure for future smart grids. In this system, multi-energy, direct current (DC), and alternating current (AC) power are decoupled by a larger DC-link capacitor. However, bulk capacitors prevent the achievement of high power density and high reliability of this system. To address this issue, active power decoupling control for a single-phase three-port conversion system is proposed in this paper. Owing to its low internal impedance, the inherent double-line-frequency ripple power in a single-phase system can be actively absorbed by a Li-ion battery pack, with a sinusoidal charging/discharging technique, in the proposed control strategy. Therefore, the capacitance of the DC-link capacitors can be significantly reduced. Further, a DC-link voltage ripple resonant compensation control loop was developed to ensure single-phase ac power quality on the grid side. Finally, the experimental results obtained from a 2.5 kVA single-phase three port power conversion prototype verify the feasibility and performance of the proposed control strategies.

Discrete-Time Modeling of High Power Asymmetric Half-Bridge LED Constant-Current Driver Controlled by Digital Current Mode

The high-power Asymmetric half-bridge Converter (AHBC) LED constant current driver controlled by digital current mode is a fourth-order system. Static operating point, parasitic resistance, load characteristics, sampling effect, modulation mode and loop delay will have great influence on its dynamic performance. In this paper, the small-signal pulse transfer function of the driver is established by the discrete-time modeling method for two operating points with three modulation modes of trailing-edge, leading-edge and double-edge. And, the effects of parasitic parameters, delay, sampling and load etc. are fully considered in modeling. For a large number of complex exponential matrix operations, the first order Taylor formula is used for approximate calculation after the coefficient matrix is obtained by substituting the data. Then, the designed average current mode compensators based on state-space averaging small-signal model(SSA) are used for analog and digital control, and the loop characteristics and control performance are analyzed. Simulation and experimental comparison results show that the proposed discrete-time model(DTM) can more accurately describe the characteristics of resonant peak, high-frequency dynamic and loop delay, and is very suitable for the design of high frequency digital controller.