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Wireless, passive, and cost-efficient monitoring of moisture within packaged food and medicine is important to ensure their safety and freshness. This paper presents paper-based single spiral inductance–capacitance (LC) sensors and a distance-insensitive readout system. The parasitic capacitance of the single-spiral coil is used to form an LC resonant circuit with its inductance. The printing paper is utilized as a humidity sensing material. A model for the LC sensor is analyzed and compared with HFSS simulation, showing the relative error within 6.3%. Nano-silver paste for the single-spiral coil was screen printed on the printing paper. The LC sensors with 4, 6, and 8-turns coils were characterized at relative humidity levels of 15%-90%RH by a readout coil at a fixed position. Comparison shows that the 8-turn sensor has the best linearity with respect to humidity. The sensitivity and response time were measured to be 120 kHz/%RH and 60 minutes, respectively, with the hysteresis errors less than 0.9%. During the practical monitoring, the tested signal frequency will have a shift if the coil’s relative position alters. To weaken the influence of the coil’s position, a readout coil, working at the quasi-resonant with the LC sensor was utilized to enhance the readout, resulting in more stable signal. According to the experimental results, the improved readout system can restrain the frequency shift within 1.1% at a readout distance from 2–50 mm when the ambient humidity is 60%RH. [ABSTRACT FROM AUTHOR]

This letter describes a single-transistor oscillator implemented on a paper substrate at the operating frequency of 24 GHz, based on a design procedure that makes it possible to overcome the limitations caused by thin high-loss substrates and package parasitics of commercial components. The commercial transistor adopted in the oscillator is led to instability by exploiting its parasitic gate inductance. The drain network compensates for the parasitic inductance of the transistor package and connects the oscillator circuit to a 50- $\Omega $ load resistance. Finally, an external inductor at the source terminal is used to resonate out the capacitive contribution of the circuit at the oscillation frequency. Overall, the active device appears in a quasi-common-drain stage. Experimental results on prototype show that the oscillator exhibits an output power of +6.2 dBm at 24 GHz, with a dc power consumption of 72.5 mW. [ABSTRACT FROM AUTHOR]

This paper presents a digital gyroscope interface system for high-frequency bulk-acoustic-wave (BAW) gyroscopes with in-run automatic mode-matching (AMM) capability. The presented work demonstrates the design and implementation of the dual-mode (DM) operation architecture on a flexible digital platform, which allows for low-cost rapid development and evaluation of new functions and architectures. Two prototype silicon BAW gyroscopes are tested on this platform using the proposed system to verify the advantages of the DM architecture. The AMM in DM showed below 4-ppb mode split accuracy and fast converge time without overshoot or oscillation. The DM operation with in-run AMM substantially reduced the bias drift of the gyros, leading to significantly lower rate random walk (RRW) compared to conventional single-mode (SM) operation. The performance repeatability and stability over the temperature of the DM gyro system are characterized, showing as high as $50\times $ improvement compared to the SM architecture. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate for the first time that a 19-bit chipless tag based on a paper substrate can be realized using the flexography technique, which is an industrial high-speed printing process. The chipless tag is able to operate within the ultra-wide band (UWB) and has a reasonable size (7\times 3 cm^2) compared to state-of-the-art versions. Thus, it is possible to use this design for various identification applications that require a low unit cost of tags. Both the simulation and measurement results are shown, and performance comparisons are provided between several realization processes, such as classical chemical etching, flexography printing, and catalyst inkjet printing. [ABSTRACT FROM PUBLISHER]

In this letter, a chipless radio frequency identification (chipless-RFID) system with erasable/programmable 40-bit tags inkjet printed on paper substrates, where tag reading proceeds sequentially through near-field coupling, is presented for the first time. The tags consist of a linear chain of identical split ring resonators (SRRs) printed at predefined and equidistant positions on a paper substrate, and each resonant element provides a bit of information. Tag programming is achieved by cutting certain resonant elements, providing the logic state “0” to the corresponding bit. Conversely, tags can be erased (all bits set to “1”) by short circuiting those previously cut resonant elements through inkjet. An important feature of the proposed system is the fact that tag reading is possible either with the SRR chain faced up or faced down (with regard to the reader). To this end, two pairs of header bits (resonators), with different sequences, have been added at the beginning and at the end of the tag identification chain. Moreover, tag data storage capacity (number of bits) is only limited by the space occupied by the linear chain. The implementation of tags on paper substrates demonstrates the potential of the proposed chipless-RFID system in secure paper applications, where the necessary proximity between the reader and the tag, inherent to near-field reading, is not an issue. [ABSTRACT FROM PUBLISHER]

The impedance expansion method (IEM), which has been previously proposed by the authors of this paper, is a circuit modeling technique for electrically very small devices. This paper describes a circuit modeling procedure that utilizes the IEM and eigenmode analysis for a wireless power transfer system. First, a multimode circuit model that can represent the higher order resonances in a broadband frequency range is presented. Subsequently, a single-mode circuit model—consisting only of passive elements—that can represent both the radiated and conduction loss powers at approximately its operating frequency band is presented. [ABSTRACT FROM AUTHOR]

In this paper, an inkjet-printed electromagnet-based touchpad employing spiral resonators is proposed. The proposed touchpad is fabricated by a direct patterning method using an inkjet printer with a conductive silver nanoparticle ink. The conductive patterns are easily printed on a paper substrate and sintered for achieving good conductivity. The proposed touchpad is composed of two spiral resonators that resonate at 0.94 GHz ( f1 ) and 1.83 GHz ( f2 ), respectively. When the first resonator is touched, f1 decreases from 0.94 to 0.81 GHz because of electromagnetic (EM) coupling between the finger and the spiral resonator. Similarly, when the second resonator is touched, f2 decreases from 1.83 to 1.55 GHz. Owing to the EM coupling distance between the spiral resonator and the finger, the frequency changes although the finger does not reach beyond a height of 1.27 mm on the spiral resonator. The performance of the proposed touchpad is validated using simulation and measurement results. [2016-0035] [ABSTRACT FROM AUTHOR]

Copyright of Journal of Synthetic Crystals is the property of Journal of Synthetic Crystals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a metamaterial inspired radio frequency touchpad sensor system based on two split ring resonators (SRRs) realized on a Rogers/Duroid 5870 with 2.33 dielectric constant = 2.33, loss tangent = 0.0012, and thickness = 0.8 mm. The touchpad consists of two SRRs resonating at $f_{1} = 2.74$ GHz and $f_{2} = 3.86$ GHz. When a finger is placed on SRR 1, $f_{1}$ changes from 2.74 to 2.57 GHz due to electromagnetic coupling between the SRR and the finger, and similarly, $f_{2}$ changes from 3.86 to 3.76 GHz. The proposed touchpad system can detect a finger wearing a glove, in contrast to capacitive touchpads utilized in contemporary smart phones. We demonstrated 56- and 49-MHz frequency shifts for $f_{1}$ and $f_{2}$ , respectively, with 1.66-mm total thickness (0.69-mm-thick photo paper and 0.97-mm-thick glass slide). [ABSTRACT FROM AUTHOR]

This paper presents a measurement-based method for real-time determination of the wind farms or wind turbines that contribute most significantly to a subsynchronous resonance (SSR) event. The method is based on the concept of subsynchronous power (SSP). This paper has shown that it is the SSP that drives the SSR. By monitoring the direction and amount of SSPs produced by different wind farms or turbines, the most critical wind farms or turbines can be identified and quantified. A dq0 transform-based algorithm is developed to calculate the SSP in real time. The method overcomes the interference of fundamental frequency components and non-steady-state SSR components on the extraction of the SSP component. Several test cases have demonstrated the usefulness of the proposed concept and method. [ABSTRACT FROM AUTHOR]

This research paper presents experimental investigations conducted on electromechanical systems with distributed parameters in their mechanical parts, exploring their behavior in both the frequency and time domains. The study emphasizes the significance of considering parameter distribution in such systems and identifies the most influential element responsible for their distributed characteristics. The experiments were performed across various technological fields, illustrating the relevance and broad applicability of the findings. To conduct the experimental research, a comprehensive setup was developed, utilizing a range of measuring devices to capture relevant data. The paper outlines the design and implementation of a software and hardware complex, integrating StrimServer and CANMonitor programs, which played a crucial role in data acquisition and analysis. Additionally, the research delves into the development of a control system, detailing the process of creating the simplest corrective device. The study elucidates the element responsible for processing information as part of a module and highlights the programming environment utilized for developing the control program. A set of programs for programming a controller is also presented. The obtained results from the experiments in the frequency domain demonstrate valuable insights into the behavior of electromechanical systems with distributed parameters. Furthermore, the study presents experiments conducted with and without the developed methodology for synthesizing the control system, showcasing the effectiveness of the proposed approach. The accuracy of the experimental results is validated through a careful comparison with theoretical calculations. The maximum relative error between theoretical and experimental outcomes is found to be within 10%, affirming the reliability of the theoretical calculations for engineering purposes. In the time domain analysis, the paper showcases current graphs obtained using the CANMonitor program at different oscillation frequencies. Notably, the study reveals a significant increase in current amplitude at the resonant frequency, providing crucial information for understanding and designing electromechanical systems with distributed parameters. The results presented in this paper can provide a strong foundation for further advances and applications in the mining and material handling industries. [ABSTRACT FROM AUTHOR]

This paper discusses a recent event in the western American power system when a forced oscillation was observed at a frequency that was close to a well-known 0.38-Hz inter-area electromechanical mode frequency of the western system. The event motivates a systematic investigation in this paper on the possibility of resonant interactions between forced oscillations and electromechanical inter-area oscillatory modes in power systems. When the natural oscillatory mode of a power system is poorly damped, and the forced oscillation occurs at a frequency close to system mode frequency at critical locations for the mode, resonance is observed in simulation test cases of the paper. It is shown that the MW oscillations on tie-lines can be as high as 477 MW from a 10-MW forced oscillation in Kundur test system because of resonance. This paper discusses the underlying system conditions and effects as related to resonance in power systems caused by forced oscillations and discusses ways to detect such scenarios using synchrophasors. Simulated data from Kundur two-area test power system as well as measurement data from western American power system are used to study the effect of forced oscillations in power systems. [ABSTRACT FROM AUTHOR]

Studying the electromechanical response behavior of piezoelectric thin films under different loading conditions is of great value for the development and optimization of piezoelectric sensors and flexible portable electronic devices. This paper establishes the theory of large deflection vibration of rectangular four-edge simply supported piezoelectric thin films using the energy method, and analyzes the electromechanical response characteristics of vibration force (including resonant frequency and nonlinear vibration). Meanwhile, the electromechanical response behavior of Poly(vinylidene fluoride) (PVDF) films under different loading conditions (static and harmonic vibration) is analyzed. The study investigates the nonlinear vibration characteristics and resonance frequency variations under different film sizes and thickness conditions in the case of various loading conditions. The developed model can predict the resonance frequency associated with the plate dimensions. This study is of great significance for the research and application of laminated piezoelectric film sensors. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents abstracts on applied psychopathology and biofeedback, presented at the 36th Annual Meeting of the Association for Applied Psychophysiology and Biofeedback. These include "The Use of Biofeedback and Relaxation Model of Costochrondritis in Childhood: A Clinical Case Examination," "The Effects of Ampliture Training on Measures of Coherence in QEEG," "Paradoxes in Biofeedback and Neurofeedback," and "Biofeedbak Treatment of Severe Psychogenic Cough."

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Compared to traditional antennas, microstrip antennas offer numerous advantages, such as low prices, low weight, ease of feeding, and attractive radiation characteristics. A microstrip antenna is a radiator covered with a dielectric cover layer for protection from rain, snow, and other environmental conditions. When placing the dielectric cover layer on the microstrip patch antenna, it effects the antenna parameters. In particular, the resonant frequency is lowered, causing tuning problems and severely degrading the antenna performance. This paper discussed the effect of cover layer thickness on antenna parameters such as resonant frequency, gain, bandwidth, beam-width, VSWR, return loss, and radiation patterns. The proposed patch antenna is designed for an S-band frequency of 2.4 GHz. The proposed antenna is used in wireless and bluetooth applications. This paper experimentally studies the effects of cover layer thickness on microstrip patch antennas. [ABSTRACT FROM AUTHOR]

This paper aims at comparing micromachined cantilever structures with the purpose of providing design guidelines towards high performance energy harvesters such that they provide a good output power, resonant frequency and volume tradeoff, while considering microfabrication process limitations. Increasing the power output of piezoelectric energy harvesters by tapering the beams has been presented as promising solution in the literature. This paper investigates the power output of several geometric variations of cantilever beams, and examines the advantages of balancing the strain distribution throughout the beam. A comparison of the impact of different geometries is presented, and recommendations are given. Namely, eight rectangular and trapezoidal T-shaped designs are fabricated and benchmarked. Their resonant frequencies and power outputs are compared for the same available area ($1800\,\,\mu \text{m}\times 800\,\,\mu \text{m}$). Measurements show that the trapezoidal designs can have a higher output power depending on the beam length to mass length ratio, in comparison to the rectangular T-designs that have lower frequencies. Resonant frequencies ranging from 2.9 to 7.2 kHz and power outputs ranging from 2.2 to 7.1 nW are reported. [ABSTRACT FROM AUTHOR]

This letter proposes a frequency-reconfigurable dipole antenna using an origami flasher. The dipole antenna is designed on flat paper in the unfolded state, and the paper can then be folded into a cube inspired by the origami flasher. Dipole length is extended in the folded state due to the patch pole, which acts as a dummy in the unfolded state. The proposed origami antenna can switch resonance frequency from 1.23 to 0.77 GHz by folding the paper. Measured return losses are 11.6 and 13.9 dB, peak gains are −0.48 and −3.41 dBi, and efficiencies are 90% and 20% at each resonance frequency in the unfolded and folded states, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we describe the implementation and test of a biaxial optical accelerometer based on fiber Bragg gratings using ultra-high numerical aperture (UHNA) optical fiber. The characteristics of the UHNA optical fiber, such as the decrease of the fiber Bragg gratings reflectivity after the sensor mounting, were compared with the GF1 photosensitive one. The proposed sensor enables to measure acceleration in two orthogonal directions, making it suitable for vibration analysis in electrical machines and structural health monitoring. The initial project was based on finite-element analysis, experimental test, and analytical response, where it was possible to predict the resonant frequency of the mechanical system of approximately 650.00 Hz. After mounting with the optical fiber, the system was characterized allowing the determination of the resonant frequencies in both sensitive directions; the values of 1232.50 Hz and 1272.50 Hz were estimated for the $x$ -axis and the $y$ -axis. This paper enabled to validate the application of the UHNA optical fiber in the development of small sensors and high radius of curvatures, thus providing the motivation for future applications. [ABSTRACT FROM AUTHOR]

This paper presents a new bandwidth tuning theory for Butterworth-response resonator filters. The presented theory shows that the bandwidth of odd-order Butterworth filters can be varied by adjusting only two interresonator coupling structures while maintaining a perfect impedance matching at the center frequency. In other words, this paper presents an analytic approach to reduce the number of tunable coupling structures when designing a bandwidth-tunable resonator filter. Theories for third- and fifth-order direct-coupled filters are discussed in detail, and it is shown that only two interresonator coupling structures are required to be tunable. In addition, for verifying the new bandwidth tuning method, a fifth-order cylindrical cavity filter has been designed, fabricated, and measured. The fabricated filter has an 11:1 bandwidth tuning range. [ABSTRACT FROM AUTHOR]

This paper is focused on using plasma as element of a frequency selective surface (FSS). FSSs have been used for filtering electromagnetic waves for many years. Conventional FSSs use metal patch pattern as periodic element. This paper takes the plasma tube as a substitution for metal patch. The 3-D finite-difference time-domain method with periodic boundary condition is utilized to simulate the interaction of incident wave and plasma FSS. Numerical calculation results in that electron number density of plasma can dominate the resonance frequency obviously. The resonance frequency increases as the increasing of electron number density of plasma to the limit of that of perfectly electric conductor. Thus, the FSS can be designed to be tunable by changing the ionized electron number density. Both of the noncollision and collisional plasma model are introduced to study the FSS characteristics. The numerical calculation results show that the collision frequency only influences the reflectivity while has no effect on the resonant frequency. The resonant frequency and transmitted power ratio can be tuned by assigning the plasma’s electron number density and collision frequency. Thus, plasma elements offer the possibility of improved shielding effect along with reconfigurability. Plasma FSS can also be made transparent by tuning the plasma off which makes the use of FSS more versatile. [ABSTRACT FROM AUTHOR]

The latest developments in dc transformer technology are enabling larger and more complex dc power distribution systems. However, the literature is scarce regarding the investigation and quantification of its impact on the dc grid. Therefore, this paper analyses the impact of the dc transformer location on the system’s characteristics to provide enough information to predict the system performances for future dc grids. To determine the critical resonant frequencies of the system, the power converters outer control loop dynamic are included to provide a better representation in frequency domain, and enable its evaluation for the addition of new equipment to the power distribution network. The proposed solution has an expansible methodology, allowing its application in large systems and easy impedance response assessment. Moreover, the proposed solution is independent of the ac grid backup solutions, allowing the dc power distribution network planning to deal only with the dc variables. Finally, theoretical developments are validated using simulations, and the steady-state and impedance identification process is described in detail. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study, implemented for the equivalent circuit model (ECM), concerning the bandwidth in square-loop frequency-selective surfaces (FSSs). For the square-loop ECM, there is no formulation to quantify the effects of dielectric supporting layers, geometric features, and incident wave properties on the FSS bandwidth. Hence, it is not possible to control or evaluate the bandwidth of the FSS in the design from the knowledge of these parameters. In this paper, we addressed this issue using the ECM as an analysis method. In the first part of this study, we considered the square-loop FSS with thin dielectric supporting layers, where the bandwidth was expressed as a function of geometric parameters, incidence angle, and polarization of the incident wave as well as a factor that takes into account the effective permittivity of the dielectric support. Particle swarm optimization method was used to synthesize square-loop FSSs via the ECM with a specific resonant frequency and bandwidth requirements. In the second part, the behavior of bandwidth as a function of dielectric thickness was obtained by using a matrix cascading technique (MCT), implemented with ECM and a model for the dielectric effective permittivity. This approach takes into account the modifications on bandwidth due to multiple reflections on dielectric boundaries and allows calculating its value for any dielectric thickness and configuration. It is remarkable the low computational cost and acceptable accuracy obtained with the proposed approaches. All simulation results using ECM and MCT were compared with Ansys-HFSS commercial software simulations. [ABSTRACT FROM AUTHOR]

This paper presents a fully-printed chipless radio frequency identification sensor tag for short-range item identification and humidity monitoring applications. The tag consists of two planar inductor–capacitor resonators operating wirelessly through inductive coupling. One resonator is used to encode ID data based on frequency spectrum signature, and another one works as a humidity sensor, utilizing a paper substrate as a sensing material. The sensing performances of three paper substrates, including commercial packaging paper, are investigated. The use of paper provides excellent sensitivity and reasonable response time to humidity. The cheap and robust packaging paper, particularly, exhibits the largest sensitivity over the relative humidity range from 20% to 70%, which offers the possibility of directly printing the sensor tag on traditional packages to make the package intelligent at ultralow cost. [ABSTRACT FROM PUBLISHER]

This paper presents a detailed review of the design aspects and performance analysis of high-frequency inverters used in inductive power transfer application (IPT) for electric vehicles. The paper's main scope is focused on the design of inverters used explicitly for wireless charging with misalignment variations and coil dimensions. The research articles in the literature focus on the high-power transfer and coil structures for the existing topologies. The magnetic resonance coupling in the IPT system depends on the resonance phenomenon. The operating frequency of the inverter must be the same as the resonant frequency in the compensation network. On complete assessments, the paper emphases on suitable inverter specifications for wireless charging and its related issues. In addition, the resonant inverters can be replaced with H-bridge inverters in consideration of voltage stress and harmonic control. Investigations on harmonic elimination strategies for H-bridge and resonant inverters are also discussed in the paper. [ABSTRACT FROM AUTHOR]

Filter capacitors are among the most serious noise sources in HVDC converter stations, and there are still no satisfactory noise reduction measures. This paper proposes the use of the mass tuning (MT) method to adjust the vibration frequency response characteristics and to realize vibration control and noise reduction. First, the theoretical model of the MT structure is developed based on continuum mechanics. Based on the theoretical model, it is revealed that inserting an MT component into the capacitor element package will cause a decrease in the resonant frequencies and antiresonant frequencies. Furthermore, the movement degree of the resonant frequencies increases as the position of the MT component becomes closer to the package end, while the movement degree of the antiresonant frequency is the largest when the MT component is located in the middle of the package model. The vibrations and the noise levels of an example MT capacitor are then compared with the results of an original capacitor. The comparison results show that the MT scheme designed in this paper can achieve a noise reduction effect of 12–15 dB(A). The proposed reduction method is proven to be both effective and efficient. [ABSTRACT FROM AUTHOR]

Conveyor belt-type checkweigher is a widely used industrial system, whose periodic disturbances generated by the mechanical vibration parts (such as the operating motors, the gears, and the rollers) deteriorate the measurement accuracy of the weighing signal. The conventional way of suppressing these disturbances is using low-pass filters, which cannot meet the requirement if the conveyor belt is operating at a high speed (usually higher than 1.0 m/s). In this paper, the digital multiple IIR notch filter-based on a novel design method is proposed to remove these periodical noises. And the conventional low-pass filters and the wavelet signal denoising method are compared with the method proposed in this paper, the results show that the new method can achieve greater performance. Finally, an experimental platform of checkweigher is built and the mean errors and the standard deviations of the error about the tests in-field can meet the requirements of category XIII(1) in OIML R 51 with the conveyor belt running speed up to 2.0 m/s. [ABSTRACT FROM AUTHOR]

This paper proposes miniaturized, lightweight and high sensitivity planar metamaterial based sensors for relative permittivity measurement within [0.9–10.9] GHz band. Each proposed sensor is designed using a thin-substrate microstrip line loaded with a single complementary split ring resonator (CSRR). The loaded resonator is excited using maximum electric/magnetic (cross polarization) excitation to maximize the sensors’ sensitivity. Each proposed sensor operates at different frequency range within [0.9–10.9] GHz band based on the size of the loaded resonator. Compared to similar state-of-the-art sensors, the proposed ones are at least 30% more sensitive. The minimum transmission frequency shifts (50)% as the sample’s relative permittivity changes from 1 to 10. The paper proposes a condition of sensitivity uniformity to maintain a uniform sensitivity over the specified band irrespective of the resonator size. Utilizing the proposed condition, the sensitivity of all sensors remains uniform throughout [0.9–10.9] GHz band for all dielectric samples with relative permittivity between 1 and 10. This vital feature allows the practical realization of resonant probes with less computational operations and consistent measurements over a wide dynamic range of the sensing-related frequency. Experimental measurements are in good agreement with the numerical findings. The paper includes a comprehensive sensitivity analysis which investigates the effect of resonator’s excitation scheme, resonator’s order (i.e. single or double CSRR) and substrate thickness on the sensitivity of CSRR based sensors. The proposed sensing platforms are recommended for the development of highly sensitive, consistent and reliable planar sensors such as microfluidics, displacement, nondestructive and biomedical sensors. [ABSTRACT FROM AUTHOR]

Power grids have recently become more susceptible to sub-synchronous control interactions (SSCI) due to the increasing penetration of renewable resources and series-compensated lines. SSCI is a purely electrical and fast-growing phenomenon. Therefore, without an expeditious detection and mitigation solution, it can cause serious damage to renewable and transmission facilities, consequently leading to cascading outages. This paper proposes an effective algorithm to detect SSCI within 45 ms and reliably send a trip signal within 95 ms. First, a comprehensive SSCI analysis is suggested to improve the preprocessing of the measured signal. Then, the proposed algorithm utilizes mode identification approaches in conjunction with a moving fast fourier transform (FFT) to capture and process the frequency and magnitude of oscillations to issue a reliable trip command in the case of an SSCI event. To evaluate the algorithm, a portion of the Electric Reliability Council of Texas (ERCOT) grid with relatively high penetration of renewable generation resources is utilized. The proposed detection algorithm is implemented on a real-time target device and is tested with an SSCI signal from the ERCOT grid under real-time operating conditions. The results indicate the efficiency and accuracy of the method with successful detection within the acceptable time frame. [ABSTRACT FROM AUTHOR]

An intrinsically switchable and frequency reconfigurable bulk acoustic wave filter bank based on ferroelectric barium strontium titanate (BST) is presented. Ferroelectric BST possesses electric-field-induced piezoelectricity, enabling the design of voltage-controlled acoustic devices, including thin-film bulk acoustic resonators and solidly mounted resonators. In this paper, a triple-band switchable filter bank, consisting of three 2.5-stage filters based on BST FBARs, is designed, simulated, and fabricated for the first time. The bandpass filters have center frequencies at 1.85, 1.96, and 2.04 GHz and are selectively turned on based upon the external dc bias voltage applied to each filter. Turning off all the filters provide an isolation of more than 27 dB between the input and output ports. The presented intrinsically switchable ferroelectric filter bank potentially simplifies future radio frequency front ends by integrating both switching and filtering functionalities onto a single device and reduces the overall circuit area. [ABSTRACT FROM AUTHOR]

In this paper, a compact log-periodic dipole array (LPDA) antenna is developed at 0.5–10 GHz. This LPDA structure constitutes fewer dipole elements than a conventional LPDA antenna that exhibits similar resonant frequencies. In the design of a miniaturized LPDA antenna, various size-reduction techniques have been proposed in the open literature to decrease the lateral size of a conventional LPDA. However, little or no attention has been focused on reducing the size of the LPDA antenna by shortening the boom or axial length. In pursuit of reducing the total length of a conventional LPDA, a dual-band dipole antenna is proposed as the radiating elements for the LPDA antenna in this paper. The proposed dipole structure is a printed half-wave principal dipole loaded with a pair of resistive structures via subfeeding lines. A pair of resistive loads forms the auxiliary (secondary) dipole of the proposed dipole antenna. The structure of the proposed dual-band dipole is achieved without a ground plane as opposed to many existing dual-band antenna types. As a result, the dipole antenna has a simple geometry with omnidirectional characteristics. Also, the feeding structure of this dipole can provide an extra degree of freedom to tune the antenna for matching purposes. A 25-element LPDA antenna is designed with a much reduced boom length compared with existing LPDA structures. To confirm the feasibility of the technique, the experimental results of the proposed LPDA prototype were analyzed and juxtaposed with a benchmark LPDA. [ABSTRACT FROM AUTHOR]

This paper describes a highly sensitive sensing system for remote sensing applications. Typically, a resonant sensor based on film bulk acoustic resonator (FBAR) requires a frequency counter, impedance analyzer, or network analyzer to measure the shift of the resonant frequency. This paper presents a hand-held, low-cost but highly sensitive sensing system built with an FBAR-based oscillator and a phase-locked-loop for ppm-level detection of frequency shift as well as signal processing. The achieved voltage-frequency sensitivity is 1.035 V/kHz with the minimum detectable frequency shift of 4.81 ppm (5.21 kHz) and the dynamic range of 134 ppm (145 kHz). Also, the output of the sensing system is purposely designed to be a DC voltage that is linearly related to the frequency shift. To our knowledge, it is the first FBAR-based sensing system that converts the frequency shift to DC voltage. [ABSTRACT FROM AUTHOR]

This paper offers a new approach for far-field high-resolution imaging of conducting obstacles based on arrays of frequency-multiplexed subwavelength resonant elements. Each resonator is a circular aperture in a metallic screen that is strongly miniaturized by means of loading by a thin epsilon-negative and near-zero metamaterial (MTM) liner. Each MTM-lined aperture exhibits a fano-shape transmission profile, i.e., a peak followed by a minimum, and the resonance frequencies of different apertures are chosen such that the resonance of one lies within/very close to the antiresonance of the other to ensure strong decoupling. This paper shows that blocking an aperture using a conducting disc removes the corresponding resonance peak/minimum from the transmission/far-field amplitude spectrum, enabling far-field detection of any distribution of such obstacles with a spatial resolution determined by the aperture sizes, which measure less than one-sixth of free-space wavelength at their respective resonance frequencies. The proposed imaging mechanism is verified through full-wave HFSS simulations as well as far-field measurements. Some challenges associated with this approach are then discussed. [ABSTRACT FROM AUTHOR]

This paper addresses an efficient way of conversion of ambient vibrational energy to electrical by structure optimization of piezoelectric film. Polyvinylidene fluoride has been used for this study. The effects of shape variations of cantilever beam with multilayer configuration based on Euler–Bernoulli theorem without considering the proof mass attached at the free end has been investigated in this paper. Most of piezoelectric vibrational energy harvesters are designed considering the presence of proof mass and in this paper it has been tried to convey the idea, that with the new optimized shape, the cantilever itself can behave as a flexible proof mass for energy enhancement. The possibility of harvesting energy from three different geometries: 1) near edge width quadratic (NEWQ), 2) half quadratic (HQ), and 3) Trapezoidal has been presented. Scanning electron microscopy is used to measure the thickness of the various layers. The NEWQ design shows the best performance in terms of power and resonance frequency ( $\text{f}_{\text {r}}<200~\text {Hz}$ ) compared with the others. Here, the study of the piezo-film models using finite element method simulation software (COMSOL Multiphysics optimization module) and experimental validation are also presented. Using the models, the generation of voltage/power has been analyzed under various excitation frequency and load resistance. Moreover, stress/strain distribution and the displacement have also been highlighted in this paper. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of a novel class of substrate-integrated waveguide (SIW) filters, based on partially air-filled cavity resonators. Removing the dielectric in a portion of the SIW cavity allows obtaining dual-mode cavities: such cavities represent a doublet, used as the building blocks in the design of filters. A thorough modal analysis of the air-filled resonant cavity based on transmission lines’ representation and a detailed study of the doublet permit to demonstrate a full control of the operation frequency, pass bandwidth, spurious-free region, and position of the transmission zeros of the filter. This paper presents the design, fabrication, and measurement of several two-pole filters based on this concept, with the aim to show the capabilities of the proposed structure and of the design technique. A five-pole filter is also presented, to describe the extension of the proposed approach to higher order filters. [ABSTRACT FROM PUBLISHER]