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In this paper, a grounded meminductor emulator has been proposed using six MOSFETs (3NMOS and 3PMOS) only. Three transconductance stages and two capacitors are generally required to realize a meminductor emulator. Meminductor is considered as an inductor having memory. In the proposed design of meminductor emulator, the gyrator circuit is realized using common-source and common-gate amplifiers with one capacitor. The first capacitor is used to obtain the behaviour of inductance while the second capacitor is used for charge storage which acts as a memory element. In the proposed design of meminductor emulator, the gate-to-source capacitor of MOSFET is utilized in place of external capacitor for memory element. Therefore, the proposed design is free from the requirement of passive components as the required capacitor is formed by MOSFET. Also, the frequency characteristics of proposed meminductor are found to be satisfactory up to 100 MHz. The other essential characteristics such as non-volatility test, temperature analysis, tunability, Monte Carlo, and corner analysis are also found to be satisfactory. The proposed design of meminductor emulator is compared with other existing meminductor emulators. The performance of the emulator is successfully verified through the realization of chaotic oscillator circuit. [ABSTRACT FROM AUTHOR]

The transformer is an important component of electrical engineering for many applications including those for integrated circuits. For integrated circuit applications, the use of a synthetic transformer has been recognised to be a viable option for a number of applications. This paper presents two new designs of electronically-controllable CMOS active transformers. The first preposition is based upon a capacitive T-network embedded between two active CMOS gyrators each of which has been obtained by a parallel back-to-back connection of one non-inverting and other inverting electronically-controllable CMOS transconductor. This circuit requires thirty-two MOSFETs, all operating in saturation region. The second design simulates an inductive T-network using two CMOS electronically-controllable floating inductors and one electronically-controllable CMOS grounded inductor thereby employing eighty MOSFETs. The first design offers the advantage of realising a step up as well as step down transformer by appropriate selections of the transconductances of two transconductors. The second design although uses a larger number of MOSFETs than the former but has the advantage of using three grounded capacitors which is a desirable from the view point of IC implementation. It may also be mentioned that using more MOSFETs does not increase layout area significantly since the capacitors require more layout area than all the MOSFETs put together. The workability of both the designs, along with their various performance characteristics and non-ideal analysis, has been well corroborated by computer simulations using SPICE software using 0.18 µm CMOS technology parameters. The application of the proposed circuits in the design of double tunned band pass filter has also been shown and its workability too has been validated by computer simulations using SPICE software. [ABSTRACT FROM AUTHOR]

A new CMOS implementation of active inductor circuit based on the gyrator-C which is suitable for low-voltage and RF applications is presented in this paper. One of the critical features of active inductors which directly affect their quality factor is their series-loss resistance. In this regard, a multi-regulated cascade stage is employed in the new structure which decreases loss. Moreover, by cascading input transistor, the transistors which determine the self-resonance frequency and quality factor will be separated from each other. This results in arranging properties of designed active inductor independently. The configuration of two-stage conventional gyrators is improved which gives the proposed design more opportunities in determining and tuning its characteristics. Also by employing common-source configuration, low conductance nodes are achieved which decrease the ohm-loss of AI. Furthermore, main properties of design can be tuned without affecting each other. The power consumption of the circuit remains as low as 0.62 mW, then the circuit is suitable for low power applications. The results showed that AI is suitable for RF applications over 0.2–11.8 GHz frequency range. In order to verify theoretical calculations, simulations are carried out using HSPICE and level 49 parameters (BSIM3v3) in 130 nm CMOS technology. In addition, Corner and Monte Carlo analyses are considered to prove the efficiency of the circuit against the process variation. [ABSTRACT FROM AUTHOR]

A novel nonlinear encryption–decryption system based on a joint transform correlator (JTC) and the Gyrator transform (GT) for the simultaneous encryption and decryption of multiple images in grayscale is proposed. This security system features a high level of security for the single real-valued encrypted image and a high image quality for the multiple decrypted images. The multispectral or color images are considered as a special case, taking each color component as a grayscale image. All multiple grayscale images (original images) to encrypt are encoded in phase and placed in the input plane of the JTC at the same time without overlapping. We introduce two random-phase masks (RPMs) keys for each image to encrypt at the input plane of the JTC-based encryption system. The total number of the RPM keys is given by the double of the total number of the grayscale images to be encrypted. The use of several RPMs as keys improves the security of the encrypted image. The joint Gyrator power distribution (JGPD) is the intensity of the GT of the input plane of the JTC. We obtain only a single real-valued encrypted image with a high level of security for all the multiple grayscale images to encrypt by introducing two new suitable nonlinear modifications on the JGPD. The security keys are given by the RPMs and the rotation angle of the GT. The decryption system is implemented by two successive GTs applied to the encrypted image and the security keys given by the RPMs and considering the rotation angle of the GT. We can simultaneously retrieve the various information of the original images at the output plane of the decryption system when all the security keys are correct. Another result due to the appropriate definition of the two nonlinear operations applied on the JGPD is the retrieval of the multiple decrypted images with a high image quality. The numerical simulations are computed with the purpose of demonstrating the validity and performance of the novel encryption–decryption system. [ABSTRACT FROM AUTHOR]

A scalable, passive galvanic isolator, consisting of a ferrite/piezoelectric magnetoelectric (ME) composite with a coil wound round it, was fabricated and developed. In this scheme, the two ports of the isolator exhibit corresponding inductive/capacitive behaviors, and an induced impedance difference facilitates a high isolation realization for signal transferring/blocking. Non-reciprocity of the device was characterized and verified by its mutual transfer impedance. In addition, a key parameter defined by the self-impedance transfer ratio of |Z22|/|Z11| was introduced to quantitatively describe the isolating performance, and the measured |Z22|/|Z11| reached as high as 1220 at the optimum bias of H = 190 Oe. The proposed ferrite/piezoelectric ME isolator exhibiting significant desired properties is of importance for signal propagation/blocking due to its impedance difference and non-reciprocity. [ABSTRACT FROM AUTHOR]

A novel optical signature and authentication cryptosystem is proposed by applying triangular association encryption algorithm (TAEA) and 3D Arnold transform in Gyrator domains. Firstly, a triangular association encryption algorithm (TAEA) is designed, which makes it possible to turn the diffusion of pixel values within bands into the diffusion within and between bands. Besides, the image signature function is considered and utilized in the proposed cryptosystem. Without the image signature, the original image cannot be restored even if all of the keys are obtained. Moreover, the image integrity authentication function is provided to prevent pixel values from being tampered with. Through the numerical simulation of various types of attacks, the effectiveness and capability of the proposed hyperspectral data signature and authentication cryptosystem is verified. [ABSTRACT FROM AUTHOR]

New methods and apparatuses for information security have evolved as a result of the rapid expansion of optical information processing. Security is one of the major issues in digital image transmission because it can deliver very secret information to any corresponding agency such as the military, biomedical, and security agencies. Previously, various techniques are proposed to perform optical image encryption techniques using different transformation and pixel-level techniques. Each work has its advantages and disadvantages in terms of computational complexity, security level, flexibility, quality, and so on. To overcome the security issues present in the previous works, a novel optical image encryption standard is proposed in this paper. This work uses information hiding followed by image encryption using Gyrator Transform (GT) using mean gradient key-based block swapping techniques. The main advantage of this work is that the key generation is dynamic and it depends upon the pixel intensity of 8 × 8 blocks. Secret information hiding is performed in the Discrete Cosine Transform (DCT) domain to protect the data against noise attacks. To analyze the performance, various evaluation metrics are used to measure the quality of the decrypted image under various distortions such as cropping and rotation. The robustness of information hiding is analyzed using a noise attack on the received image. This work achieved 45.6 dB of Peak Signal-to-Noise Ratio (PSNR) and 0.965 of Structural Similarity Index (SSIM), which is the best when compared to the conventional image encryption standards. [ABSTRACT FROM AUTHOR]

The Hannay geometric phase is the classical analog of the well-known Berry phase. Its most familiar example is the effect of the latitude λ on the motion of a Foucault pendulum. We describe an electronic network whose behavior is exactly equivalent to that of the pendulum. The circuit can be constructed from off-the-shelf components using two matched transconductance amplifiers that comprise a gyrator to introduce the non-reciprocal behavior needed to mimic the pendulum. One may precisely measure the dependence of the Hannay phase on λ by circuit simulation and by laboratory measurements on a constructed circuit. [ABSTRACT FROM AUTHOR]

A beneficial methodology of heavy rare earth dysprosium doping in spinel nickel-zinc ferrites host lattice for improving the gyration effects of magnetoelectric (ME) gyrators was presented, and the physical and magnetic properties of synthesized ferrites, dynamic magneto-mechanical responses, and non-reciprocal current–voltage conversions and power conversion efficiency were systematically characterized. Taking advantage of the strong magneto-crystalline anisotropy of dysprosium-induced large lattice distortions, piezo-magnetic coefficient can be improved effectively and eventually the PE. Experimental results demonstrated that the maximum $V/I$ and $I/V$ coefficients are 1609 V/A and 4.2 mA/V at optimum dysprosium concentration of $x = 0.4$ , which are 165% and 122% times higher than that in samples without rare earth doping, respectively. These finding provided great possibilities to advance this presented method and optimized ME gyrators into actual applications as energy efficient $I$ – $V$ converters for power electronics. [ABSTRACT FROM AUTHOR]

This paper presents the design of gyrator-C active inductor. Current reuse technique reduces the noise of transconductor in gyrator. Bandpass filter and voltage-controlled oscillator (VCO) are designed based on the proposed active inductor. Post-layout simulations and PVT analysis are carried out using 180 nm RFCMOS technology at 1.8 V supply voltage. Bandpass filter with center frequency 2.45 GHz attains a noise figure of 6 dB. VCO with a tuning range of 1.5 GHz–2.8 GHz attains a phase noise of −99.86 dBc/Hz. The active area occupied by bandpass filter and VCO are 150 μm × 150 μm and 145 μm × 145 μm respectively. • Current reuse technique is used to realize the negative transconductor in gyrator-C to reduce the noise contribution. • An additional design freedom to tune self-resonant frequency and Q factor of the active inductor an active resistor is used. • A bandpass filter with tuning range 1.6 GHz-2.9 GHz is designed based on the proposed active inductor that occupies less area. • VCO is designed based on the proposed active inductor with a tuning range and phase noise on a par existing designs. [ABSTRACT FROM AUTHOR]

Exceptional points of degeneracy (EPD) can enhance the sensitivity of circuits by orders of magnitude. We show various configurations of coupled LC resonators via a gyrator that support EPDs of second and third-order. Each resonator includes a capacitor and inductor with a positive or negative value, and the corresponding EPD frequency could be real or imaginary. When a perturbation occurs in the second-order EPD gyrator-based circuit, we show that there are two real-valued frequencies shifted from the EPD one, following a square root law. This is contrary to what happens in a Parity-Time (PT) symmetric circuits where the two perturbed resonances are complex valued. We show how to get a stable EPD by coupling two unstable resonators, how to get an unstable EPD with an imaginary frequency, and how to get an EPD with a real frequency using an asymmetric gyrator. The relevant Puiseux fractional power series expansion shows the EPD occurrence and the circuit's sensitivity to perturbations. Our findings pave the way for new types of high-sensitive devices that can be used to sense physical, chemical, or biological changes. [ABSTRACT FROM AUTHOR]

We study the rise of exceptional points of degeneracy (EPD) in various distinct circuit configurations such as gyrator-based coupled resonators, coupled resonators with PT-symmetry, and in a single resonator with a time-varying component. In particular, we analyze their high sensitivity to changes in resistance, capacitance, and inductance and show the high sensitivity of the resonance frequency to perturbations. We also investigate stability and instability conditions for these configurations; for example, the effect of losses in the gyrator-based circuit leads to instability, and it may break the symmetry in the PT-symmetry-based circuit, also resulting in instabilities. Instability in the PT-symmetry circuit is also generated by breaking PT-symmetry when one element (e.g., a capacitor) is perturbed due to sensing. We have turned this instability "inconvenience" to an advantage, and we investigate the effect of nonlinear gain in the PT-symmetry coupled-resonator circuit and how this leads to an oscillator with oscillation frequency very sensitive to perturbation. The circuits studied in this paper have the potential to lead the way for a more efficient generation of high-sensitivity sensors that can detect very small changes in chemical, biological, or physical quantities. [ABSTRACT FROM AUTHOR]

This work introduces a new low‐noise current‐reused CMOS active inductor (AI) based on Gyrator‐C configuration. In the proposed AI, a simple common‐source amplifier is utilised for boosting effective Gm and improving noise performance of the AI. While the Gm‐boosting technique improves the noise performance as well as the quality factor of the inductor, a resistor is also added to the feedback path for more quality factor improvement. Rigorous analysis of the proposed circuit shows a significant noise performance and quality factor enhancement. In order to verify the concept and confirm the mathematical analysis, the AI is designed and simulated in a commercial 0.18 μm RF‐CMOS technology. The simulation results show that the proposed inductor operates in 1 to 7.2 GHz frequency range, has a 9 nH inductance at 2.864 GHz frequency and 650 μW total power dissipation at 1.8‐V supply voltage. Maximum quality factor of 90 is achieved at 2.864 GHz frequency and a quality factor greater than 40 is obtained from 2.4 to 3.3 GHz. The input‐referred current noise of the proposed inductor is as low as 22 pA/√Hz showing 30.5% improvement compared to the conventional AI. The proposed AI is also tunable and sweeping the tuning voltage results in changing extracted inductance from 4.35 to 15.2 nH with only a chip area of 0.003 mm2. Post‐layout and different Monte Carlo simulation results also confirm the robust operation of the proposed AI against different process non‐idealities. [ABSTRACT FROM AUTHOR]

The encryption and privacy protection of multimedia image resources are of great value in the information age. The utilization of the gyrator transform domain model in multimedia image encryption can select parameters more accurately, so it has a wider scope of utilization and further ameliorates the stability of the whole system. On account of this, this paper first analyzes the concept and connotation of gyrator transform, then studies the image encryption algorithm on account of gyrator transform, and verifies the robustness of the gyrator transform algorithm under the influence of noise interference, shear attack, and other factors through the high robust multimedia image encryption and result analysis of gyrator transform. [ABSTRACT FROM AUTHOR]

An asymmetric cryptosystem is presented for encrypting multiple images in gyrator transform domains. In the encryption approach, the devil's spiral Fresnel lens variable pure phase mask is first designed for each image band to be encrypted by using devil' mask, random spiral phase and Fresnel mask, respectively. Subsequently, a novel random devil' spiral Fresnel transform in optical gyrator transform is implemented to achieved the intermediate output. Then, the intermediate data is divided into two masks by employing random modulus decomposition in the asymmetric process. Finally, a random permutation matrix is utilized to obtain the ciphertext of the intact algorithm. For the decryption approach, two divided masks (private key and ciphertext) need to be imported into the optical gyrator input plane simultaneously. Some numerical experiments are given to verify the effectiveness and capability of this asymmetric cryptosystem. [ABSTRACT FROM AUTHOR]

In this work, we propose, develop, and demonstrate a fundamental and comprehensive theoretical foundation for the first time to formulate and devise known and unknown reciprocal and/or nonreciprocal ferrite components with arbitrarily concurrent multimode features based on the substrate-integrated waveguide (SIW) technology. To achieve such a universal design, a nonreciprocal unit cell (NRUC) is first defined and characterized. Then, an approach is proposed and investigated to deploy a sufficient number of NRUCs next to each other as a kernel multimode SIW topology. The kernel configuration transforms the incident guided-wave into several separate segments, propagating in parallels independently and along each NRUC, which can be manipulated separately. This methodology grants a general solution to forge ferrite components in a multimode configuration, discussed in detail to corroborate the proposed generalized theory. Finally, two multimode components are studied and demonstrated for the first time as application examples for the proposed theory. Namely, a dual-mode circulator and a triple-mode gyrator are prototyped, fabricated, and measured, exhibiting an excellent agreement with simulation results that effectively validate the presented theoretical foundation in this work. [ABSTRACT FROM AUTHOR]

This paper presents a class of active non-reciprocal metamaterials (ANMMs) in an attempt to control the flow of acoustic waves along a one-dimensional acoustic duct. The proposed method distinguishes itself from the available approaches where the non-reciprocities are generated either actively or passively by various sources of nonlinearities, circulators and gyroscopic/gyrator components, and/or spatiotemporal modulation. The proposed method relies in its operation on a controller that is designed by simultaneous allocation of both the eigenvalues and eigenvectors. In other words, the entire eigen-structure of the closed-loop system is assigned as deemed necessary. Conventionally, the placement of the eigenvalues has been employed to enhance both the damping and response of the system. However, in this study, the focus is placed on adjusting the eigenvectors in a way that enables the spatial control and redistribution of the wave propagation along the acoustic duct in order to produce any desirable non-reciprocal behavior. During this entire process, the system continues to behave in a linear fashion. The theory governing the operation of this proposed approach is introduced, and a comprehensive experimental validation effort is presented to demonstrate the basic features, non-reciprocal behavior, and control characteristics. Generalization of the presented strategies to two-dimensional acoustic systems is a natural extension of the present work. [ABSTRACT FROM AUTHOR]

In this paper, a multi-image encryption scheme based on compressed sensing (CS) and deep learning in the optical gyrator domain is proposed. Firstly, multiple plaintext images are compressed by CS to obtain multiple measurements, and then the pixels of each measurement are scrambled by using a chaotic system. Secondly, the scrambled measurements are combined into a matrix and diffused by XOR operation with a chaotic matrix. Finally, the diffused matrix is encoded with a random phase and an optical gyrator transform to obtain a complex-valued matrix, and the amplitude of the complex-valued matrix is taken as the ciphertext. In decrypt, plaintext images are reconstructed from the CS measurements by a neural network, which achieves high reconstruction speed and quality compared with the traditional algorithm. Especially, the data amount of plaintext images can be compressed by up to 8 times while achieving high decryption quality. To our best knowledge, CS reconstruction algorithms based on deep learning is firstly used for image encryption. Moreover, the proposed scheme is highly robust against occlusion, noise, and chosen-plaintext attack. [ABSTRACT FROM AUTHOR]

An active inductor (AI) based on a cascade gyrator for 30 GHz applications implemented with a 0.25 μ m in SiGe technology is presented. The gyrator converts not only a key capacitor into an inductor, but also an added resistor, into a negative resistor. This gyrator-RC has its losses compensated by the negative resistor improving the active inductor Q factor. Changing the bias voltage and current allows to obtain a variable AI. A study of a cascade gyrator AI topology is done to understand the circuit behavior and key elements. For this purpose, an AI impedance model is introduced and discussed. An improved AI with the added resistor replaced by a voltage controlled mosfet resistor is proposed. This extra control voltage allows the variable AI quality factor fine tuning. Schematic and circuit extracted from layout simulations are presented, and compared with the measured results of two prototypes of the AIs (one with a fixed resistor and other with a voltage controlled resistor). A prototype of a high pass filter using the AI with fine Q control was fabricated. Non-linear simulations for different input signal levels were performed and compared with measurements. Also discussion on the non-linear models accuracy is performed. [ABSTRACT FROM AUTHOR]

Tunability in magnetoelectric (ME) gyrators is of importance for realizing controllable energy-efficient electronics. Here, we investigated a novel passive control method that exhibits a high frequency tunability of up to 370 Hz using a non-power-consuming (passive) capacitor approach. The method requires zero external controllable power as the frequency is changed. This tuning does not decrease the power conversion efficiency (86%) of the gyrator. Our results indicate that the internal mechanical reactive components need to be changed by passive external capacitors, which proves to be an effective way by which gyrators can achieve high tunability and retain high power conversion efficiency. This article opens an approach toward the design of new tunable circuit components. [ABSTRACT FROM AUTHOR]

A detailed analysis of an operational transconductance amplifier based gyrator implementing a fractional-order inductance simulator is presented. The influence of active element non-ideal properties on the gyrator operation is investigated and demonstrated by admittance characteristics and formulas for important values and cut-off frequencies in these characteristics. Recommendations to optimize the performance of the gyrator in terms of operation bandwidth, the range of obtainable admittance magnitude, and signal dynamic range are proposed. The theoretical observations are verified by PSpice simulations of the gyrator with LT1228 integrated circuit. [ABSTRACT FROM AUTHOR]

The effect of an external constant magnetic field on the dielectric properties and magnetodielectric (MD) coupling in La0.4Eu0.1Ca0.5MnO3 polycrystalline manganite at room temperature (RT) has been investigated. This sample exhibits negative colossal MD values under low applied magnetic fields (− 30% and − 45% under applied fields of 0.6 T and 1.2 T, respectively). The colossal MD values as well as the relatively low dielectric loss values suggest that the La0.4Eu0.1Ca0.5MnO3 sample can be a suitable␣candidate for technological applications at RT, like magnetic field sensing and gyrators. [ABSTRACT FROM AUTHOR]

A multiple cascode flipped active inductor (MCASFAI) is proposed to determine the degrees of freedom in cascode flipped active inductor (CASFAI). The inductance value of CASFAI is dependent on negative transconductor in gyrator network. This finding is in contrast to the finding that has been reported in the literature, on the degrees of freedom in CASFAI. As the transconductance of negative transconductor increases, inductance decreases, and quality factor increases. The MCASFAI proposed in this study is designed to enhance both inductance and quality factor of CASFAIs. Analytical modelling is done to determine the design parameters that affect inductance and quality factor in CASFAI. Verification is done using Cadence Virtuoso in 180 nm process. Bandpass filter based on the proposed MCASFAI is designed to operate at 2.45 GHz centre frequency with a bandwidth of 80 MHz. The designed filter attains a dynamic range of 162 dB‐Hz and figure of merit of 153 dB‐HZ/mW, which is comparable to the bandpass filter designs reported in the literature. [ABSTRACT FROM AUTHOR]

A control strategy based on matching the source and load changes of the order of milliseconds, called peer-to-peer energy transfer, is introduced. This energy transfer enables a decoupled energy transfer system in common bus networks. To realize the transfer with a pair of two-port circuits, a power gyrator is derived from the phasor-based model of a bidirectional ac/dc converter, based on the concept of a time-variable transformer. Power-gyrator timing synchronization is achieved by communication, and a peer-to-peer energy transfer system is developed. Experimental and simulation results are compared, and it is demonstrated that peer-to-peer energy transfer can be used for decoupling common bus voltage networks. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) gyrators are unique circuit elements capable of direct conversion of the current to voltage or vice versa. In order to understand the power conversion and loss processes in the gyrators, an equivalent input loss factor has been developed in this paper based on Mason's model (equivalent circuit model). This factor serves to understand the loss transferring mechanism and to evaluate the conversion efficiency for the electric power in ME gyrators. Studies have been carried out for modeling the power conversion in both the solenoid and the ME core. Several important factors have been proposed and discussed to enhance the conversion efficiencies in the electric–magnetic–mechanical three-phase conversion process. A simplification of our equations reveals that the efficiency of the ME gyrator is related to the product of the effective coupling (k2 $_{\text{eff, m}}$) and mechanical quality (Qmech). According to our model, magnetic and electric materials with highk $_{\text{eff, m}}$ andQmechvalues are the key ingredients to enhance the efficiency of ME gyrators. We have successfully realized a power efficiency of 92% based on a Metglas/hard-PZT ME gyrator, which showed a good correlation to the predicted values. [ABSTRACT FROM AUTHOR]

Magnetoelectric (ME) gyrators consisting of system of Sm-doped NiZn ferrites (Ni1-xZnxSm0.02Fe1.98O4, 0.2≤x≤0.5) and piezoelectric ceramics [Pb(Zr, Ti)O3] with coil wound around have been developed. Distinct hysteresis behaviors were observed in off-resonance ME couplings and power conversion efficiency (PE) characterizations, resulting in a non-zero ME response and anticipating a higher remanent PE at zero bias. Consequently, light samarium doping facilitates the enhancement of PE, which reaches its maximum of 81.5% under optimum bias and self-biasing value of 58.5% under zero bias in the composite of Ni0.8Zn0.2Sm0.02Fe1.98O4/PZT trilayer respectively, exhibiting approximately 2.2 times higher than the counterpart without any samarium doping. These findings provide great possibilities of ME gyrators for miniaturized devices deployed in power electronics, converters and wireless energy harvesters without a sacrifice in magneto-mechanical efficiency. [ABSTRACT FROM AUTHOR]

A novel tuning principle for simple gyrator-based CMOS active inductor (AI) circuit is presented. The method makes use of Widlar current source to enhance the quality factor. The simulation of the proposed AI provides a maximum quality factor of 1819 at 2.88 GHz. The AI shows the inductive bandwidth of 1.66 GHz to 3.16 GHz and power consumption of 6.87 mW. The other characterization factors such as linearity, supply voltage sensitivity and noise analysis are discussed. The performance of the tunable AI using Widlar current source are compared with the same using a simple current mirror. An AI using a conventional current mirror (CCM) and Widlar current source have been implemented in the 0.18 μ m CMOS technology. [ABSTRACT FROM AUTHOR]

Objective(s): Regarding the global burden of uropathogenic Escherichia coli (UPEC) infections, prevention and treatment of such infections play a significant role in healthcare management. The inordinate use of fluoroquinolones led to a worldwide spread of quinolone-resistant strains. Therefore, this study aimed to investigate mutations in codons 83 and 106 of gyrA gene in UPEC isolates in the north of Iran. Materials and Methods: This cross-sectional study performed on a total of 223 UPEC isolates which were recovered within 6 months in 2017. Isolates were identified and confirmed by standard microbiologic tests, and antimicrobial susceptibility testing was carried out by disk diffusion and E-test methods. PCR reaction was performed to amplify gyrA gene, and PCR-RFLP was performed using BsiEI and BstUI restriction enzymes to investigate mutations in gyrA gene. Results: The nalidixic acid, ciprofloxacin, ofloxacin, and norfloxacin resistance rates were 61.9%, 50.2%, 48.25, and 45.3%, respectively. Overall, 55.2% of E. coli isolates had a mutation in gyrA gene in codon 83, and 20.2% in codon 106. Also, 15.2% of isolates had simultaneously mutation. Moreover, a significant association was found between mutations in gyrA gene and quinolone and fluoroquinolones resistance pattern of UPEC isolates. Conclusion: Our results revealed a high level of quinolone resistance associated with the mutations in gyrA among the clinical isolates of UPEC in our region. To the best of our knowledge, this study is the first investigation on the role of gyrA alteration in quinolone resistance among UPEC isolates from the north of Iran. [ABSTRACT FROM AUTHOR]

Nonreciprocal components, such as isolators and circulators, are critical to wireless communication and radar applications. Traditionally, nonreciprocal components have been implemented using ferrite materials, which exhibit nonreciprocity under the influence of an external magnetic field. However, ferrite materials cannot be integrated into IC fabrication processes and, consequently, are bulky and expensive. In the recent past, there has been strong interest in achieving nonreciprocity in a nonmagnetic IC-compatible fashion using spatio-temporal modulation. In this paper, we present a general approach to nonreciprocity based on switched transmission lines. Switched transmission lines enable broadband, lossless, and compact nonreciprocity and a wide range of nonreciprocal functionalities, including nonreciprocal phase shifters, ultra-broadband gyrators and isolators, frequency-conversion isolators, and high-linearity/high-frequency/ultra-broadband circulators. We present a detailed theoretical analysis of the various nonidealities that impact insertion loss and provide design guidelines. The theory is validated by experimental results from discrete-component-based gyrators and isolators and a 25-GHz circulator fabricated in a 45-nm SOI CMOS technology. [ABSTRACT FROM AUTHOR]

This paper presents a volume integral equation (VIE) solver for the forward electromagnetic scattering of 3-D inhomogeneous biaxial anisotropic objects embedded in uniaxial anisotropic media. The optical axes of the objects can be rotated with arbitrary angles. The mixed-order basis functions are employed to discretize the VIE, i.e., the flux densities $(D, B)$ are expanded by the volumetric rooftop basis functions and the vector potentials $(A, F)$ are expanded by the second-order curl conforming basis functions. The weak form of the VIE is formulated by testing it using the same volumetric rooftop basis function and solved by the biconjugate gradient stabilized fast Fourier transform (BCGS-FFT) method. Several numerical simulations of different shapes anisotropic objects are performed and the results are compared with commercial software simulations to validate the accuracy and efficiency of the proposed solver based on different discretization schemes. The major new contribution of this paper is that not only the scatterer but also the background medium is magnetodielectrically anisotropic. Therefore, the dyadic Green’s function for the uniaxial anisotropic background medium is evaluated before solving the VIE. [ABSTRACT FROM AUTHOR]

The structural, electrical and magnetic properties of nickel substituted zinc ferrites (NixZn1−xFe2O4, x = 0.3, 0.4, 0.5, 0.6 and 0.7) have been investigated. The phase purity of these samples is characterized by X-ray diffraction method, which indicates that all the samples are single phase in nature. The elements compositions analyzed by EDS are well matched with the expected stoichiometric ratio and are homogenous distributed in samples. The frequency dependence of dielectric constant curve displays a normal dielectric behavior, while the dielectric loss is found to be abnormal, exhibiting a loss peak at certain frequency for some of the Ni-Zn ferrites. The M-H curves for all samples exhibit typical soft ferromagnetic characteristics. The saturation magnetization as a function of Ni2+ concentration is firstly strengthened and then weakened, reaching a maximum value of 80.23 emu/g at x = 0.5. The Ni2+ concentration dependence magnetization can be understood by the enhancement of magnetic exchange interaction for low substitution content and the decrease of net magnetic moment for high substitution content. [ABSTRACT FROM AUTHOR]

A series of cobalt substituted nickel ferrite nanoparticles with nominal compositions, Ni(1−x)Co(x)Fe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) have been synthesized by gel process. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer. The XRD spectra revealed that all the samples are of single phase spinel structure and the average size of nanocrystallite was calculated for a sample by the full width at half maximum (FWHM) of the strongest XRD peak. These sizes are small enough to achieve the suitable signal to noise ratio for the high density recording media. The lattice constant (a), X-ray density (ρx) and cell volume (V) are also calculated from XRD data. Experimental, theoretical lattice constant (aexp, ath), tetrahedral and octahedral radii (rA and rB), tetrahedral and octahedral bond length (dAx and dBx), tetrahedral edge (dAxE), shared octahedral edge (dBxE) and unshared octahedral edge (dBxEU) of the annealed Ni-Co ferrite nanoparticles increase with the increase in Co doping. Morphology of the samples was investigated by a FE-SEM. The FTIR spectra of the spinel phase calcinated at 600 °C exhibit two prominent fundamental absorption bands in the range of 350-610 cm−1 assigned to the intrinsic stretching vibrations of the metal at the tetrahedral and octahedral sites. The specific saturation magnetization (Ms), remanent magnetization (Mr) and the coercivity (Hc) of the spinel ferrites are further improved by the substitutions of Co+2 ions. The values of Ms for NiFe2O4 and CoFe2O4 are found to be 60.92 and 70.59 emu/g, respectively and Hc are in the range of 452.12-1026 Oe. The process is investigated with simultaneous thermogravimetric-differential thermal analysis (TG-DTA). The role played by the Co ions in improving the structural and magnetic properties are analyzed and understood. Our simple, economic and environmental friendly preparation method may contribute towards the controlled growth of high quality ferrite nanopowders and a potential candidate for recording media application. [ABSTRACT FROM AUTHOR]

Non-reciprocal phase shifters have been attracting a great deal of attention due to their important applications in filtering, isolation, modulation, and mode locking. Here, we demonstrate a non-reciprocal acoustic phase shifter using a simple acoustic waveguide. We show, both analytically and numerically, that when the fluid within the waveguide is biased by a time-independent velocity, the sound waves travelling in forward and backward directions experience different amounts of phase shifts. We further show that the differential phase shift between the forward and backward waves can be conveniently adjusted by changing the imparted bias velocity. Setting the corresponding differential phase shift to 180 degrees, we then realize an acoustic gyrator, which is of paramount importance not only for the network realization of two port components, but also as the building block for the construction of different non-reciprocal devices like isolators and circulators. [ABSTRACT FROM AUTHOR]

There is no standard accepted by highway authorities on the compaction procedures of 100 mm diameter gyratory compactor specimens. In previous studies on gyratory compaction, the utilisation of either coring from 150 mm specimens or preparing taller specimens than the usual 63.5 mm long Marshall specimens has been undertaken. The utilisation of 150 mm mould sizes introduces an important amount of mechanical disturbance during the coring process of 100 mm diameter specimens out of them. The novelty of the present study is that a new standard for preparing gyratory compactor specimens with a diameter of 100 mm and length of approximately 63.5 mm by utilising polypropylene fibers of 3 mm multifilament for the modification has been proposed for the first time. To achieve optimal conditions, in addition to gyratory compaction, modified bitumen samples’ physical properties, especially rotational viscosities, were also investigated in a detailed manner. Physical and mechanical tests have been carried out using the specimens prepared by changing the main testing parameter of gyration number from 30 to 70. The design gyration number of 100 mm polypropylene fiber reinforced dense bituminous mixtures has been determined as 33 under medium traffic conditions. [ABSTRACT FROM AUTHOR]

A digital scheme based on singular value decomposition (SVD) encrypted using Gyrator transform is proposed to enhance the security of the system. In this technique, plain input image is multiplied with another image and is then masked with random phase mask (RPM) along with Double random Phase Encoding (DRPE) in gyrator domain. Then obtained image is decomposed into segments [U, S, V] using SVD and is then each decomposed segment is randomized to get three encrypted image. It will increases the key space and also increases the number of parameters which makes it difficult for an attacker to find exact key to recover original image. The robustness of the proposed cryptosystem has been analysed on the basis of different parameters by simulating on MATLAB 8.1.0 (R2012b). The experimental results are provided to highlight the effectiveness, robustness and suitability of the proposed cryptosystem and to prove the feasibility and validity of the proposal. [ABSTRACT FROM AUTHOR]

This paper deals with application of simple synthetic inductor with series resistance (non-ideal gyrator). Those inductors are seldom used. However, if we use this inductor in the arm of bridge, the circuit is able to achieve high performance. In this way we can get band stop filter with good performance. In the paper we solve influence of real OPA properties. Theoretical considerations are verified by means of simulations (MicroCap) and experiments. Based on theoretical considerations, simulations and experiments are finally determined by criteria that must meet real operational amplifier to make the circuit performed well. [ABSTRACT FROM AUTHOR]

The dynamics of a simple autonomous jerk circuit previously introduced by Sprott in 2011 are investigated. In this paper, the model is described by a three-time continuous dimensional autonomous system with an exponential nonlinearity. Using standard nonlinear techniques such as time series, bifurcation diagrams, Lyapunov exponent plots, and Poincaré sections, the dynamics of the system are characterized with respect to its parameters. Period-doubling bifurcations, periodic windows, and coexisting bifurcations are reported. As a major result of this work, it is found that the system experiences the unusual phenomenon of asymmetric bistability marked by the presence of two different attractors (e.g., screw-like Shilnikov attractor with a spiralling-like Feigenbaum attractor) for the same parameters setting, depending solely on the choice of initial states. Among few cases of lower dimensional systems capable of such type of behavior reported to date (e.g., Colpitts oscillator, Newton–Leipnik system, and hyperchaotic oscillator with gyrators), the jerk circuit/system considered in this work represents the simplest prototype. Results of theoretical analysis are perfectly reproduced by laboratory experimental measurements. [ABSTRACT FROM AUTHOR]

A generic algebraic model of switched-resonator converters is developed and demonstrated by published and new converter configurations data. The model hinges on a newly introduced multiport global-gyrator matrix, of which the classical two-port gyrator is a private case. The main attribute of the skew-symmetrical as well as a Toeplitz global-gyrator matrix is that it expresses the magnitude and directions of the currents as a linear function of the port voltages with a constant gyration factor. The model is verified by previously published data, as well as new experimental and simulation results. [ABSTRACT FROM AUTHOR]

This paper introduces a new voltage regulator module (VRM) that merges a highly efficient switched-inductor converter as the main unit with a load-side switched-capacitor-based converter to assist during load transient events. The resulting hybrid-VRM exhibits improved dynamic performance for both loading and unloading transient events, while maintaining a compact design with reduced output capacitance and lower components stress. The hybrid controller that has been developed allows operation that is based on output voltage measurement alone, further reducing the circuit complexity. A power processing efficiency analysis that has been carried out shows efficiency improvement in favor of the hybrid-VRM when compared to time-optimal control under varying load conditions. The operation of the VRM is verified on a 20-W, 12V-to-1.5-V prototype with peak power conversion efficiency of 93%, demonstrating near-ideal transient recovery. [ABSTRACT FROM AUTHOR]

Non-reciprocal phase shifters have been attracting a great deal of attention due to their important applications in filtering, isolation, modulation, and mode locking. Here, we demonstrate a non-reciprocal acoustic phase shifter using a simple acoustic waveguide. We show, both analytically and numerically, that when the fluid within the waveguide is biased by a time-independent velocity, the sound waves travelling in forward and backward directions experience different amounts of phase shifts. We further show that the differential phase shift between the forward and backward waves can be conveniently adjusted by changing the imparted bias velocity. Setting the corresponding differential phase shift to 180 degrees, we then realize an acoustic gyrator, which is of paramount importance not only for the network realization of two port components, but also as the building block for the construction of different non-reciprocal devices like isolators and circulators.

The paper analyses two main types ofgyrator-like dc-dc switched converters encounteredin dc power management. The first type consists of areactive reciprocal two-port network insertedbetween two bridges of ideal switches. The powertransfer from source to load is controlled bymodifying the delay between the switching bridges.The second type is a buck converter with anappropriate sliding mode control, suitable forparalleling multiple converters.

The paper introduces and analyses the results of an experimental trial on the fatigue resistance of recycled hot mix asphalt for road pavements. Based on the gyratory compaction and the indirect tensile strength test, the mix design procedure has optimized nine different mixes, considering both conventional limestone and Reclaimed Asphalt Pavement (RAP), the latter used at different quantities, up to 40% by weight of the aggregate. A standard bitumen and two polymer modified binders were used for the production of the mixes. The fatigue study was carried out with four-point bending tests, each one performed at 20°C and 10 Hz. The empirical stiffness reduction method, along with the energy ratio approach, based on the dissipated energy concept, was adopted to elaborate the experimental data. Unaged and aged specimens were checked, to analyse the ageing effects on the fatigue performance. In comparison with the control mixes, produced only with limestone, improved fatigue performance was noticed for the mixtures prepared with RAP, especially when made with polymer modified binders, under both aged and unaged conditions. Both the approaches adopted for the experimental data analysis have outlined the same ranking of the mixes. [ABSTRACT FROM AUTHOR]

A systematic synthesis approach for floating gyrators employing single z‐copy current‐controlled current conveyor trans‐conductance amplifier (CCCCTA) is presented in this work. Initially, the pathological models of two types of the CCCCTA, namely z‐copy z+‐output CCCCTA (CCCCTA+) and z‐copy z−‐output CCCCTA (z‐copy CCCCTA−), are derived by virtue of the nodal admittance matrix (NAM) expansion method. Moreover, these models are then used in the synthesis of floating gyrator using single z‐copy CCCCTA. Two floating gyrators are acquired by expanding the NAM of floating gyrator. The synthesised gyrators employ one z‐copy CCCCTA and a grounded admittance. Adjusting bias currents of the CCCCTA can tune the parameter of the gyrators. The hand analysis and PSPICE simulation show that the used synthesis method is simple, systematic and valid. [ABSTRACT FROM AUTHOR]

SEM analyses of W-Ti and W-V alloys produced by a powder metallurgy route have revealed the presence of Ti or V pools with different sizes and shapes. The larger pools have sizes between ~ 0.3 and several microns and are embedded between the matrix grains. The smaller Ti-rich (V-rich) particles, with sizes below ~ 0.3 μm, are spherical and are dispersed inside the matrix grains. The characteristics of the second phase nanoparticles have been studied using the SANS technique. The scattering curves have been analyzed in terms of a polydisperse particle system following the Beaucage approach, and the maximum entropy method to obtain the particle size distributions. Beaucage analyses suggest the presence of two particle populations, characterized by radii of gyration from 50 to 80 Å (population I) and between 650 and 760 Å (population II). The volume distribution obtained by the maximum entropy approach reveals a prominent peak with particle diameter of 60 Å and ~ 70 Å for the W-Ti and W-V alloys, respectively. Secondary peaks in the size range 100–300 Å could be associated with the particle population with the larger radius of gyration. [ABSTRACT FROM AUTHOR]

In this paper, first, it is found that not only the magnetically coupled inductors but also all inductive power transfer systems (IPTSs) inherently have the nature of a gyrator. Widely known characteristics of IPTSs such as impedance inversion and source-type conversion are proved to be the nature of the gyrator. A graphical approach that utilizes the gyrator is proposed for the modeling of IPTSs in general. The proposed graphical technique enables manipulations on the circuit diagram instead of on the circuit equations, which are difficult to handle when the system order is higher than 4. Hence, the equivalent model can be obtained almost by inspection conveniently, giving fruitful physical insights that are limitedly achieved with the equation manipulations. Steady-state analyses at any frequency are possible, and equivalent series resistances can also be included in the proposed model. Five selected electrical characteristics, i.e., source-to-load gain, load-independent output voltage/current characteristics, power factor at the source, sign of the source phase angle, and allowances of open/short loads are evaluated for three widely used IPTS topologies. Also, this technique is extended to the mistuned case for verifying the general use of the approach. An experimental prototype of the voltage-source-type inductor–capacitor–inductor secondary-parallel (V-LCL-P) topology was built to demonstrate the proposed approach for both perfectly tuned and mistuned situations at 85 W and 100 kHz. [ABSTRACT FROM AUTHOR]

This paper explores the potential and limitations of analog integrated circuit techniques for the simulation of low-loss or lossless 1D or 2D transmission mediums. In this approach, a transmission line is mapped into a ladder consisting of N identical LC elements, each modeling a finite length increment of the line. Inductors are then emulated by a gyrator-capacitor combination, yielding a classical transconductor-capacitor (gm-C) circuit, suitable for integration. The validity of this approximation is discussed in the context of fault location in power networks, an application based on the electromagnetic time-reversal method. Design constraints on gm-C circuits are derived and non-ideal effects such as finite open-loop gain and component mismatches are evaluated. It is shown that a simple analog implementation can locate the fault within 1 % accuracy with a significant speed advantage over classical computational methods, reducing the processing time to <100 ms. [ABSTRACT FROM AUTHOR]

In this paper, a general analysis of the generation for all possible fractional order oscillators based on two-port network is presented. Three different two-port network classifications are used with three external single impedances, where two are fractional order capacitors and a resistor. Three possible impedance combinations for each classification are investigated, which give nine possible oscillators. The characteristic equation, oscillation frequency and condition for each presented topology are derived in terms of the transmission matrix elements and the fractional order parameters $$\alpha $$ and $$\beta $$ . Mapping between some cases is also illustrated based on similarity in the characteristic equation. The use of fractional order elements $$\alpha $$ and $$\beta $$ adds extra degrees of freedom, which increases the design flexibility and frequency band, and provides extra constraints on the phase difference. Study of four different active elements, such as voltage-controlled current source, gyrator, op-amp-based network, and second-generation current-conveyor-based network, serve as a two-port network is presented. The general analytical formulas of the oscillation frequency and condition as well as the phase difference between the two oscillatory outputs are derived and summarized in tables for each designed oscillator network. A comparison between fractional order oscillators with their integer order counterparts is also illustrated where some designs cannot work in the integer case. Numerical Spice simulations and experimental results are given to validate the presented analysis. [ABSTRACT FROM AUTHOR]

The small-signal pathological models and equivalent circuits of various CCCIIs are initially developed in this paper. The models are then used in the synthesis of floating gyrators using the CCCIIs. Three different topological types of the floating gyrators, the type I, II and III gyrators, are acquired by the NAM expansion method. The first, employing four CCCIIs, has 96 equivalent realizations, the second, employing two CCCIIs and one BOCCCII, has 32 equivalent realizations, the third, employing one BOCCCII or one BOICCCII and one DOCCCII−, has four equivalent realizations. The analysis and simulation of synthesized circuits show that the used synthesis method is simple, systematic, valid, and powerful. [ABSTRACT FROM AUTHOR]