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We study the problem of minimising the connection time between non-equilibrium steady states of the Brownian gyrator. This is a paradigmatic model in non-equilibrium statistical mechanics, an overdamped Brownian particle trapped in a two-dimensional elliptical potential, with the two degrees of freedom (x, y) coupled to two, in principle different, thermal baths with temperatures Tx and Ty, respectively. Application of Pontryagin's Maximum Principle reveals that shortest protocols belong to the boundaries of the control set defined by the limiting values of the parameters (k, u) characterising the elliptical potential. We identify two classes of optimal minimum time protocols, i.e. brachistochrones: (i) regular bang–bang protocols, for which (k, u) alternatively take their minimum and maximum values allowed, and (ii) infinitely degenerate singular protocols. We thoroughly investigate the minimum connection time over the brachistochrones in the limit of having infinite capacity for compression. A plethora of striking phenomena emerge: sets of states attained at null connection times, discontinuities in the connection time along adjacent target states, and the fact that, starting from a state in which the oscillators are coupled, uncoupled states are impossible to reach in a finite time. [ABSTRACT FROM AUTHOR]

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]

In this paper, we propose an optical image encryption scheme based on modified 3D double-phase encoding algorithm (3D-DPEA) in the gyrator transform (GT) domain, in which a plaintext is encrypted into two sparse volumetric ciphertexts under the constraints of chaos-generated binary amplitude masks (BAMs). Then, the two volumetric ciphertexts are multiplexed into the corresponding 2D ciphertexts for convenient storage and transmission. First, due to the synergistic adjustment of the two sparse volumetric ciphertexts during the iterative process, the 3D-DPEA would achieve higher recovery quality of the decrypted image with fewer iterations. In addition, because the BAMs are generated by the logistic-tent (LT) chaotic map which is closely related to the rotation angles of GT, and the LT chaotic map has several advantages such as nonlinear, pseudorandom behavior, and high sensitivity of initial conditions, the sensitivity of the secret key could be significantly improved by several orders of magnitude, reaching up to 10−14. As a result, the 3D-DPEA scheme not only eliminates the explicit/linear relationship between the plaintext and the ciphertext but also substantially enhances security. For decryption, the corresponding decrypted image can be achieved by recording an intensity pattern when a coherent beam crosses two sparse volumetric ciphertexts sequentially. Furthermore, BAMs wouldn't impose an additional burden on the storage and transmission of secret keys. A series of numerical simulations are performed to verify the effectiveness and security of the proposed encryption scheme. [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]

To enhance the stabilizing function and boost the output power of the inductive coupling power transfer (ICPT) system, a power stabilization control method based on LCL‐P resonance compensation for a wireless energy transmission system is proposed. “L” represents inductance, “C” represents capacitance, “LCL” refers to the primary‐side compensation structure, and “P” indicates that the secondary side is compensated in parallel . Firstly, this paper synthesizes the modeling principle of the gyrator equivalent model of the resonant circuit and coupled inductor, graphically analyzes the resonant compensation structure, and derives the circuit characteristics of the LCL‐P compensation structure. Then, this paper proposes an improved control strategy for the Maximum Power Point Tracking (MPPT) algorithm to dynamically track the output power and thus obtain the optimal operating point through frequency conversion. Lastly, using MATLAB/Simulink software to build the simulation model of the wireless charging system through parameter design, the impact of the conventional DC/DC power control method is contrasted with the algorithmic control suggested in this paper. The results demonstrate that: the device can realize power transfer of 2.7 KW level, the energy transfer efficiency reaches more than 90%, the inverter realizes soft‐switching operation, and the improved MPPT algorithmic control strategy proposed in this paper is utilized to achieve better closed‐loop control of the system. The excellent characteristics of the LCL‐P compensation structure in high‐power transmission applications, as well as the correctness and feasibility of the control algorithm proposed in this paper, are demonstrated through simulation and practical experiments. This is a significant step towards improving the wide‐range adaptation of the wireless charging system, which is based on the LCL‐P resonance compensation to the changes in the load and coupling. [ABSTRACT FROM AUTHOR]

In recent duration, exponential internet growth usage has necessitated robust methods for securing data during transmission. Image encryption has emerged as a crucial technique to prevent unauthorized access and manipulation of digital content. This study introduces a novel encryption method that enhances image security through a two-stage process. The first stage involves substituting and shuffling plain image pixels using a set of random numbers generated by the ISING model, where these numbers are described as a sequence of movements. In the second stage, pixel values are permuted using the Gyrator transformation, resulting in a ciphered image. Extensive numerical simulations have been conducted to calculate the effectiveness of the suggested method. The results confirm the method's efficacy, demonstrating significant improvements in security and robustness compared to existing encryption techniques. Statistical analyses further prove the advantages of using the confusion and diffusion properties for improving the proposed method. The proposed method represents a substantial improvement in the field of image encryption, presenting a secure and reliable solution for protecting digital images. [ABSTRACT FROM AUTHOR]

We propose a novel technique for multi-image encryption and hiding schemes under an optical asymmetric framework using structured fingerprint phase masks (SFPMs) in the gyrator transform (GT) domain and three-step phase-shifting digital holography (PSDH). A SFPM contains unique features of fingerprint and structured phases of the optical vortex beam, which provides enhanced security in the cryptosystem. To encrypt multiple images, GT-based phase truncation and phase reservation techniques have been used in the first level of security, whereas three-step PSDH has been used to obtain the final cipher text. The cipher text is embedded in the host image to perform the watermarking process. In this process, the host is further decomposed into three parts in which anyone from the last two parts can be used for watermark embedding, and the first part is stored as the key. The use of polar decomposition in the watermarking process provides an additional layer of security. Numerical simulations and experimental results are presented to support the proposed scheme. [ABSTRACT FROM AUTHOR]

For the analysis of color images, the single-channel processing method fails to consider the internal correlation between color components, while the quaternion matrix representation is not compact enough. To avoid these, this paper introduces trinion gyrator transform for color face image and develop a cancelable recognition scheme by jointing with randomized nonlinear PCANet. Firstly, color face images are precoded into trinion matrices and followed by a random binary amplitude mask for non-reversible. The nonlinear trinion correlation is proposed for selecting the optimal ratio. Next, the sampled matrix is modulated by using trinion gyrator transform and logistic-based random phase mask for increasing discriminability. Afterwards, the randomized nonlinear principal component analysis network is employed for extracting features. The recognition accuracy of the proposed algorithm on VIS, Aberdeen, GT and YMU datasets are up to 99.00%, 99.23%, 99.68% and 97.88%, which outperforms several existed methods. On top of that, the correlation index of generated face templates is no more than 0.26, indicating the revocability and security of the proposal. [ABSTRACT FROM AUTHOR]

Essential Secret Image Sharing (ESIS) decomposes a secret image into a set of shares that are distributed among categorized participants, and ensures that only authorized subsets of these participants can restore the image. All ESIS schemes to date have been based merely on computational techniques. In this paper, an optical ESIS system is introduced which uses unequal modulus decomposition (UMD) and optical gyrator transform (GT), offering high-speed parallel processing and dispensing with any pre-processing stages. The presented (1, 2, n) ESIS system generates n shares, including one essential share, such that any two shares that include the essential one, can reconstruct the initial secret image with no distortion. Any other unauthorized subset will not gain any information about the image. The scheme generates essential and nonessential shares that are of equal size, eliminating the need to concatenate sub-shares during the reconstruction of the secret image. The results verify that the secret image was completely retrieved in cases of authorized access, while full distortion occurred in cases of unauthorized access. The GT rotation angle serves as an additional authentication factor to validate the essential share and bolster the security. The optical ESIS system exhibits a high level of sensitivity to the changes in the GT rotation angle - that a variation of just 0.001 radians can cause the correlation coefficient to drop below 0.05. [ABSTRACT FROM AUTHOR]

In this paper, an asymmetric scheme based on double image using phase retrieval algorithms in gyrator domain is reported. The double images are encrypted using QZ synthesis method based on QZ algorithm. The synthesized image is bonded with a random phase mask and undergoes a gyrator transform. The resultant image act as an input for the phase retrieval algorithm. We have tested the scheme with five different phase retrieval algorithms, namely the Gerchberg-Saxton algorithm, modified Gerchberg-Saxton algorithm, input–output algorithm, Yang-Gu mixture amplitude-phase retrieval algorithm, and improved amplitude-phase retrieval algorithm. Simulations are executed to show the performance, feasibility, and robustness of the scheme. The gyrator parameter and private keys are highly sensitive to a small change to their original value. Performance of different phase retrieval algorithms on the scheme is evaluated using multi-attribute decision-making tool: TOPSIS method. Results suggest that the Yang-Gu mixture amplitude-phase retrieval algorithm performs better among phase retrieval algorithms and has ranked 1 in TOPSIS analysis. This has been validated by the figures reported in the paper. [ABSTRACT FROM AUTHOR]

This article establishes cutoff stability also known as abrupt thermalization for generic multidimensional Hurwitz stable Ornstein–Uhlenbeck systems with (possibly degenerate) Lévy noise at fixed noise intensity. The results are based on several ergodicity quantitative lower and upper bounds some of which make use of the recently established shift linearity property of the Wasserstein–Kantorovich–Rubinstein distance by the authors. It covers such irregular systems like Jacobi chains and more general networks of coupled harmonic oscillators with a heat bath (including Lévy excitations) at constant temperature on the outer edges and the so-called Brownian gyrator. [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]

Color images can be encrypted using a hyperchaotic system in the Discrete Cosine Transform (DCT) and gyrator transform domains. These encryption techniques provide an added layer of security to protect sensitive image data from unauthorized access or tampering. The Red, Green, And Blue (RGB) components of the original color image are encoded into two-dimensional streams, respectively. These two-dimensional streams, representing the RGB components, are then processed by the display or printing device to recreate the full-color image. This paper proposes a new image encryption scheme that integrates DCT and the gyrator transform simultaneously. This innovative approach enhances the security and robustness of image encryption, making it suitable for a wide range of applications in data protection and transmission. Specifically, four chaotic sequences generated by a hyperchaotic system are blended into streams to synthesize complex sequences. Subsequently, the two-dimensional complex streams are scrambled using the discrete cosine transform and encoded back into an image format. Finally, the parameters in the hyperchaotic system using DCT and the gyrator transform improve the security of the proposed scheme. Theoretical and experimental analyses both confirm the security and validity of the proposed work. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to propose an asymmetric double-image encryption scheme based on phase masks computed by elliptic curve cryptography. A hybrid gyrator Hartley transform augmented with an elliptic curve phase mask is used in this scheme to enhance security. Two new public decryption keys are created by encrypting the plain text with two-stage phase keys. A public key is generated during an encryption process, whereas a private key is generated before the encryption process begins. In addition to introducing nonlinearity, it enhances the security of the system. As part of the encryption operation, plain text keys are unscrambled. The system is also more resistant to selective plaintext attacks, and the decryption keys are more sensitive. Trimming the phase expands the room for the key the confidentiality of cryptography systems. An estimation of the error between the image input and the image retrieved is used to determine the effectiveness of the cryptosystem. Various potential attacks can be mitigated by the proposed technique that provides innumerable security keys. The effectiveness and security of the proposed technique are verified by numerical simulations. In order to validate and evaluate the proposed solution's viability, strength, experimental results and security analysis are presented. [ABSTRACT FROM AUTHOR]

In this note, we will explain the relationship between the fractional Fourier transform and the gyrator transform. In particular, we will show the properties of the gyrator transform, which is getting the eigenfunction and eigenvalue of the gyrator transform, recursion formula, the relation between the Wigner distribution and the gyrator transform, the differential equation satisfied with the gyrator transform of some functions, and the representation of the gyrator transform as the self-adjoint operator. Moreover, we will consider the generalized gyrator transform of tempered distributions. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this research paper is to explore the possibility to enhance the power transfer from piezoelectric energy harvester (PEH) source to the load. As the proposed gyrator-induced voltage flip technique (GIVFT) does not require bulky components such as physical inductors, it is easily realizable in small integrated circuits (IC) package thereby offering performance benefits, reducing area overhead and providing cost benefits for constrained self-powered autonomous Internet-of-Things (IoT) applications. Design/methodology/approach: This paper presents an inductorless interface circuit for PEH. The proposed technique is called GIVFT and is demonstrated using active elements. The authors use gyrator to induce voltage flip at the output side of PEH to enhance the charge extraction from PEH. The proposed technique uses the current-voltage (I-V) relationship of gyrator to get appropriate phasor response necessary to induce the voltage flip at the output of PEH to gain power transfer enhancement at the load. Findings: The experimental results show the efficacy of the GIVFT realization for enhanced power extraction. The authors have compared their proposed design with popular earlier reported interface circuits. Experimentally measured performance improvement is 1.86×higher than the baseline comparison of full-wave bridge rectifier circuit. The authors demonstrated a voltage flip using GIVFT to gain power transfer improvement in piezoelectric energy harvesting. Originality/value: To the best of the authors' knowledge, pertaining to the field of PEH, this is the first reported GIVFT based on the I-V relationship of the gyrator. The proposed approach could be useful for constrained self-powered autonomous IoT applications, and it could be of importance in guiding the design of new interface circuits for PEH. [ABSTRACT FROM AUTHOR]

This paper analyses the security of a nonlinear optical cryptosystem based on double random phase encoding (DRPE). This article is upgraded through an interference-based asymmetric optical image encryption technique, equal modulus decomposition (EMD) and deploying of the devil's vortex Fresnel Mask (DVFM). DVFM is designed by the phase values of the Devils Mask (DM),Vortex Mask(VM) and Fresnel Mask(FM). The key space of the cryptographic system increases with the use of DVFM phase keys and hybrid gyrator wavelet transform (GWT). A system's efficiency is measured by the difference between the input image and the retrieved image. The capabilities of the proposed algorithm are accomplished in terms of histograms, noise attacks and correlation coefficients. The results show that the proposed optical image encryption system based on hybrid transformation is time-efficient and provides a high degree of information security without affecting its noise immunity. In addition to offering a large number of security phase keys, it has a robust resistance to a variety of potential attacks. [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]

When a physical system evolves in a thermal bath kept at a constant temperature, it eventually reaches an equilibrium state which properties are independent of the kinetic parameters and of the precise evolution scenario. This is generically not the case for a system driven out of equilibrium which, on the contrary, reaches a steady-state with properties that depend on the full details of the dynamics such as the driving noise and the energy dissipation. How the steady state depends on such parameters is in general a non-trivial question. Here, we approach this broad problem using a minimal model of a two-dimensional nano-machine, the Brownian gyrator, that consists of a trapped particle driven by fractional Gaussian noises—a family of noises with long-ranged correlations in time and characterized by an anomalous diffusion exponent α. When the noise is different in the different spatial directions, our fractional Brownian gyrator persistently rotates. Even if the noise is non-trivial, with long-ranged time correlations, thanks to its Gaussian nature we are able to characterize analytically the resulting nonequilibrium steady state by computing the probability density function, the probability current, its curl and the angular velocity and complement our study by numerical results. [ABSTRACT FROM AUTHOR]

This paper reports a chip-scale radio frequency Lorentz-force gyrator based on an aluminum scandium nitride (Al0.7Sc0.3N) thin film. The two-port gyrator, which is essentially a lateral overtone bulk acoustic resonator, consists of a planar coil for Lorentz-force transduction and two top-bottom electrode pairs for piezoelectric transduction. The non-reciprocity is generated by the phase transition in the Lorentz-force coupling when an external vertical magnetic field is applied. The Lorentz-force gyrators based on both AlN and Al0.7Sc0.3N thin films demonstrate good non-reciprocity, i.e., the 180° phase difference, at approximately 517 and 388 MHz, respectively. Thanks to larger piezoelectric constants, the Al0.7Sc0.3N gyrator demonstrates easier impedance matching and a wider fractional bandwidth of 6.3% at a magnetic field of 1.65 T compared to 1.3% for an AlN device. Finally, an isolator consisting of the Lorentz-force gyrator and a shunt resistor is demonstrated over 35 dB of isolation and flat unidirectional transmission. [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 magnetodielectric effect has attracted considerable attention due to its intriguing physics and potential engineering applications in modern data storage, sensors, gyrators, and other novel low power electronic applications. Here, we investigate the dielectric behavior, exchange bias coupling, and magnetodielectric effect in nano-scaled CrO2/Cr2O3 core–shell structures. Importantly, our experiments have revealed interesting results whereupon the magnetodielectric effect and exchange bias coupling are strongly correlated in ferromagnetic and antiferromagnetic structures. It is notable that the magnetodielectric effect at room temperature can be enhanced from 1 to 3.5% with exchange bias coupling. Thus, the magnetodielectric effect is enhanced by as much as 250% with the assistance of exchange bias coupling. Results are interpreted here in terms of a spin-dependent transport model. [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]

A novel image encryption scheme generating visually meaningful encrypted images (VMEIs) is presented based on the gyrator transform (GT) and the Hénon chaotic map. The optical encryption system exploits the polarization degree of freedom to reduce the system complexity by allowing the use of a single GT system to concurrently apply to both the secret image and the VMEI. The cryptosystem yields a VMEI with the same size as the secret plain image, which is more secure in either storage or transmission. The results demonstrate that even if the identity of the VMEI is unveiled, any attempt to recover the original image from that VMEI −without knowing the whole secret key− will fail. Unlike previous meaningful cryptosystems that are mainly based on steganographic methods like image hiding and watermarking, the proposed optical cryptosystem adopts a non-steganographic approach by assigning an independent VMEI carrying no information related to the original secret image. The cryptosystem is verified robust against occlusion, noise, statistical attacks, as well as the classical attacks including the chosen-plaintext and chosen-ciphertext attacks. [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]

To enhance the security in optical image encryption scheme and to safeguard it from the invaders, this paper proposes a new scheme using devil's toroidal lens masks (DTLMs) and QR decomposition in gyrator transform (GT) domain. The proposed cryptosystem utilizes DTLMs which are the complex phase masks designed using the combination of a phases of devil's mask ( DM) and toroidal mask TM . QR is an operation used to decompose the matrix and is utilized to supersede the phase-truncation (PT) task in the traditional phase-truncated Fourier transform (PTFT). Hence, the proposed method is immune to the attacks to which the PTFT-based cryptosystems are vulnerable. The cryptosystem is asymmetric as both the encryption and decryption processes are different along with different encryption and decryption keys. The private keys produced during the encryption method are utilized in the decryption process to retrieve the original image. The decryption process can be realized with both the digital and the modified optical architecture. Recommended scheme strengthens the safety of DRPE by growing the key capacity and the number of parameters for safety and vigorous against diverse protection. [ABSTRACT FROM AUTHOR]

This paper deals with the modeling of sensitivity of epitaxial graphene Hall bars, from submicrometer to micrometer size, to the stray field generated by a magnetic microbead. To demonstrate experiment feasibility, the model is first validated by comparison to measurement results, considering an ac-dc detection scheme. Then, a comprehensive numerical analysis is performed to investigate signal detriment caused by sensor material heterogeneities, saturation of bead magnetization at high fields, increment of bead distance from sensor surface, and device width increase. [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]

The common-source noise-canceling (CSNC) and the gyrator are known for alleviating the trade-off between NF and S11 in wideband LNAs. Moreover, the departure of the input-matching stage and signal-amplifying stage in CSNC facilitates the design of the gyrator. Cascode configuration is exploited to boost the feedback gain, enhancing the gyrator-C effect and broadening the input-matching bandwidth. Therefore, large transistors can be used for noise reduction while maintaining a wide operating bandwidth. Post-layout simulation results in 40 nm CMOS technology show that the circuit achieves an NF of 1.37 dB–1.72 dB while maintaining a wide operation bandwidth of 100 MHz to 3.27 GHz. By contrast, the minimum NF achieved by previously published inductorless wideband LNAs is around 2 dB. Moreover, an S21 of 18.9 dB is obtained, making the design suitable for low NF receivers. Besides, the IIP3 (input third-order intercept point) of −7.1 dBm is obtained, and the circuit consumes 13.1 mW at a 1.2 V voltage supply. Being self-biased, the circuit core consumes only 0.0034 m m 2 area. [ABSTRACT FROM AUTHOR]

The enhancement of power transfer from the piezoelectric transducer to the load with a compact size is explored in this paper. Large physical inductors are no more required to create resonance in piezoelectric energy harvesting schemes while applying the proposed gyrator-induced double resonance (GI-DR) technique. Hence, the proposed circuit is cost-effective and provide improved performance along with reduced-space benefits in integrated circuits (IC) package for wireless sensor nodes (WSN) and Internet-of-Things (IoT) applications. Two cascaded gyrators are used in place of a transformer in the proposed circuit. The required phasor response for resonance is acquired by the gyrators' voltage-current (V–I) relationship. Regarding the final charging voltage, the proposed circuit with a storage capacitor of 1000 mF can obtain 763.46 % and 14.77 % improved performance than other synchronous circuits like SEH and DSSH respectively. The proposed technique can also be applied to similar piezoelectric energy harvesting strategies with large inductors to create resonance. [ABSTRACT FROM AUTHOR]

In inductorless wideband low-noise amplifier (LNA) design, input-matching is traded off with noise figure (NF). The common-source noise-canceling (CSNC) structure and the gyrator alleviate this trade-off, but the corresponding study is insufficient. This work combines the CSNC and gyrator and introduces a three-stage feedback loop to achieve high feedback gain while minimizing the added input capacitance. Hence, the trade-off between NF and input impedance matching is significantly released. Consequently, the lowest NF among inductorless LNAs was achieved, while an operation bandwidth of more than 3 GHz was obtained. Post-layout simulation results in 40 nm CMOS technology show that the circuit achieves an NF of 1.35 dB–1.7 dB while maintaining a wide operation bandwidth of 100 MHz to 3.46 GHz. As far as the author knows, this is the lowest NF inductorless LNAs have achieved. Furthermore, S21 of 10.9 dB and IIP3 (input third-order intercept point) of −5.6 dB m are obtained, and the circuit consumes 14.9 mW at a 1.2 V voltage supply. Being self-biased, the circuit core consumes only 0.0032 m m 2 die area. [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]

Recently demonstrated non-magnetic circulators rely on the interference between a linear periodically time-varying nonreciprocal gyrator and reciprocal passive microwave circuits, which limits their form factor and tunability. In this work, a new class of widely tunable non-magnetic inductorless nonreciprocal circulators based on harmonic engineering is introduced. LPTV circuits rely on modulating the input signal with a square-wave clock that contains multiple harmonics. The introduced harmonic engineering concept controls the response of the circuit to various harmonics of the clock waveform, the superposition of which results in the desired functionality. Two miniaturized N-path Shekel circulators have been implemented in 65-nm CMOS. The first prototype, which uses a four-path structure operating in the large-RC-regime, can be reconfigured for operation across 0.1–1.1 GHz with losses ranging from 2.5 to 3.4 dB. It has a form factor of (λ2/(2 × 106)) at 500 MHz, with a power consumption of 3–21 mW. The second prototype uses an eight-path structure and operates in the low-RC-regime with a tuning range of 0.28–1.15 GHz and losses of 2.3–3.3 dB and achieves more than 20-dB isolation across a 233-MHz BW (38%) within a (λ2/(1.5× 106 )) form factor at 600 MHz consuming 26–67 mW of power. To date, this work has the smallest form factor reported among the state of the art. [ABSTRACT FROM AUTHOR]

Recent research has revealed the possibility to achieve non-magnetic non-reciprocity using time variance. However, prior CMOS-based circulators rely on the interference between non-reciprocal switched-capacitor/transmission-line gyrators and reciprocal transmission-line rings, which increases form factor and restricts frequency tunability and bandwidth (BW). On the other hand, our recent work on quasi-electrostatic wave propagation in switched-capacitor networks has proposed a new regime in multipath switched-capacitor network operation that enables an ultra-broadband, ultra-compact reciprocal/non-reciprocal true-time-delay element. In this work, we corroborate these findings by implementing prototype devices of the quasi-electrostatic delay element. Our measurements of the delay element reveal that delays of tens of nanoseconds over hundreds of MHz BW are realizable on-chip in a compact form factor. In addition, we apply synthetic rotation across these switched-capacitor networks to realize an ultra-broadband N-port circulator with ultra-compact form factor. We implemented a wideband three-port circulator showcasing this new architecture in a standard 65-nm CMOS process. The circulator exhibits symmetric performance across all three ports and dc–1-GHz operation for a modulation frequency of 500 MHz. The measured transmission losses of the circulator range between 3.1 and 4.3 dB, matching is−15 dB, isolation is >18 dB, and noise figure (NF) is consistent with the insertion loss. This device occupies an area of 0.19 mm2 (λcenter2/1.9 × 106), representing about 100–1000 × higher miniaturization compared to the prior art. [ABSTRACT FROM AUTHOR]

In order to increase encryption capacity and improve transmission efficiency, this paper investigates an encryption scheme for multiple-image based on cascaded gyrator transforms and high-dimensional chaos. Firstly, each plainimage is converted into a real matrix through modulation, quaternion gyrator transform and sharing. The real matrices are connected in turn by plural coding and gyrator transforms. During the process of cascade, phase truncation and preservation operations are performed. The phase of the preceding transformation is modulated by that of the latter complex matrix to enhance security. Followed by splicing and scrambling, a real-valued ciphertext can be obtained. At the receiver end, all the plaintext images can be restituted by the reverse operation of the encryption process using the authorized keys. The adoption of high-dimensioanl chaos and Kronecker product further guarantees the security of the cryptosystem. The numerical results performed on 300 color images have demonstrated that the average PSNR of correctly decrypted images is up to 303.9939 dB, the NMSE is as low as 2.8024 × 10−28 and SSIM is equal to 1.0000. The analysis of sensitivity, statistical characteristic and robustness proves the feasibility and relibility of the proposed encryption scheme. [ABSTRACT FROM AUTHOR]

An asymmetric optical cryptosystem to encrypt images using devil's vortex Fresnel lens (DVFLs) phase masks and lower upper decomposition with partial pivoting (LUDPP) is proposed in gyrator transform domain. The proposed cryptosystem utilizes DVFLs which are the complex phase masks designed using the combination of a phases of devil's lens, vortex lens, and Fresnel lens. LUDPP is an operation used to decompose the matrix and is utilized to supersede the phase-truncation task in the traditional phase-truncated Fourier transform (PTFT). Hence, the proposed method is immune to the attacks to which the PTFT-based cryptosystems are vulnerable. The cryptosystem is asymmetric as both the encryption and decryption processes are different along with different keys. The private keys generated during the encryption process are utilised in the decryption process to retrieve the original image. The encryption and decryption process can be realised with both the digital and the modified optical architecture. In order to show the strength and robustness of the proposed encryption, a conspire numerical simulation was performed. [ABSTRACT FROM AUTHOR]

In our prior studies, we synthesized special circuits with evolution matrices featuring degenerate eigenfrequencies and nontrivial Jordan blocks. The degeneracy of this type is sometimes referred to as exceptional point of degeneracy (EPD). Our focus here is on the simplest of our circuits featuring EPDs that are composed of only two LC-loops coupled by a gyrator. These circuits, when near an EPD state, can be used for enhanced sensitivity applications. With that in mind, we develop here a comprehensive perturbation theory for these simple circuits near an EPD. Using this theory, we propose an approach to sensing, allowing one to benefit from the proximity to an EPD on the one hand when providing for stable operation on the other hand. We also address a broader scope of problems related to perturbations of Jordan blocks and their numerical treatment that allow us to effectively detect proximity to Jordan blocks. [ABSTRACT FROM AUTHOR]

We consider a model of a two-dimensional molecular machine—called Brownian gyrator—that consists of two coordinates coupled to each other and to separate heat baths at temperatures respectively Tx and Ty. We consider the limit in which one component is passive, because its bath is 'cold', Tx → 0, while the second is in contact with a 'hot' bath, Ty > 0, hence it entrains the passive component in a stochastic motion. We derive an asymmetry relation as a function of time, from which time dependent effective temperatures can be obtained for both components. We find that the effective temperature of the passive element tends to a constant value, which is a fraction of Ty, while the effective temperature of the driving component grows without bounds, in fact exponentially in time, as the steady-state is approached. [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]