Operating Frequency Range Research Articles

Innovative Decentralized Configuration Design of Chipless RFID Tag: Toward a Cost-Effective and Efficient Code Density

In this article, a compact chipless RFID tag with a small size and high data density is proposed. The tag consists of nested octagonal loops arranged in a concentric configuration. Each two neighboring resonating elements are decentrally coupled by two connector lines at obverse sides. The small size of the tag is achieved through embedding multiple octagonal elements in a nested arrangement, which share the same side, and through connecting the neighboring elements. The tag configuration is designed and optimized to improve the resonating modes with respect to the number of resonating elements. The number of generated resonating modes (N) is mathematically obtained by N= 2n-1, such (n) is the resonating elements number. An 11-bits data capacity is presented in the proposed tag within a physical dimension of 10 × 10 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , resulting high data density of 11 b/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The proposed tag is realized on Rogers RT/Duroid 5880 substrate having substrate height h=0.508 mm, relative permittivity ϵ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>r</i></sub> = 2.2, and loss tangent δ = 0.0009. The proposed tag is designed and simulated using CST Studio Suite®. The tag’s performance is initially evaluated through simulation and analyzed for effectiveness. The tag is then fabricated and measured, and the results are compared to ensure agreement between simulation and measurement. The tag advantages are compact size, high data density, and improved resonating modes. The operating frequency range of the proposed tag is 7.5 GHz–15 GHz.

Evaluation of Embedded Dual-Piezoelectric-Based Transducer With Miniature Impedance Analyzer for Monitoring the Curing of Cement Mortar

A dual-piezoelectric-based embedded transducer employing an electromechanical impedance (EMI) technique is used for monitoring the curing of cement mortar. The transducer, comprising of two piezoelectric patches pasted on a metal plate, used with a miniature impedance analyzer having a simple peak-finding algorithm, results in an economical monitoring system. The effectiveness of the system has been tested in cement mortar cubes of various sizes and showed consistent results. The measurements obtained from the miniature impedance analyzer are validated with a laboratory impedance meter. The structural (plate) resonance peaks, which were found to be only marginally affected by temperature, are quite effective in monitoring the curing. The frequency shift of the resonance peaks, which provided the indication of curing, is compared with the heat of hydration curves of the cement used. The transducer system is evaluated for different plate dimensions. The resonant peaks are a function of the geometry of the plate, including thickness. The plate size has to be selected in such a way as to keep the resonance peak frequency within the operating frequency range of the impedance analyzer. The transducer system has also been evaluated for its reusability and long-term stability.

A Planar SIW-Based Mm-Wave Frequency-Scanning Slot Antenna Array With No Scan Blindness at Normal

Planar antenna reflectors are the modern design trend of both multibeam and frequency-scanning antenna arrays. The planar implementation of reflectors is typically performed using substrate-integrated waveguide (SIW) technology. A reflector’s profile can be different from the canonical one (parabolic, elliptic, hyperbolic, etc.) because of the effect of spatial dispersion of the reflection coefficient of the SIW-based surface. It should be synthesized considering the magnitude and argument of the field reflected from such a surface to maximize the efficiency of the reflection. In this article, we present a planar millimeter-wave (mm-wave) slot antenna array with SIW-based horn–reflector feeding. We analytically formulate the optimization of the SIW surface dimensions while accounting for the spatial dispersion of the reflection coefficient. We minimize the dimensions of the planar horn–reflector feeding. Finally, we demonstrate that using a dual-slot radiating element, and we can avoid the effects of scan blindness along the normal direction. A prototype has been built and a good agreement has been achieved between the measured results and the predicted results based on calculations. The prototype achieved ±17° beam scanning within 16% of the operational frequency range, with no scan blindness along the normal direction.

Variable-Frequency and Phase-Shift With Synchronous Rectification Advance On-Time Hybrid Control of LLC Resonant Converter for Electric Vehicles Charger

The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter has been widely used in the power supply industry, such as server power, TV power, and adapter, because this converter can realize the zero-voltage switching (ZVS) at the power <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s of the primary side. Thus, the switch losses can be decreased, and the conversion efficiency can also be improved. The electric vehicle (EV) charger has been recently widely used in research and development. However, designing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converters for the wide battery voltage range is difficult because this converter is usually utilized in pulse-frequency modulation (PFM) to regulate the output voltage. This converter will also be limited to the low operating frequency range for the high conversion efficiency due to the switching frequency. By contrast, the phase-shift modulation (PSM) control for the wide output voltage range has been used at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converters. However, the ZVS will be lost due to the lagging leg of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter when the phase-shift angle is remarkably excessive. The burst-mode control has also been proposed for the converter to regulate the output voltage and maintain high conversion efficiency at light-load conditions. Therefore, this article utilized the combination of PFM, PSM, and burst-mode control for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter operating at the wide output voltage range for EV charge applications. Furthermore, this article proposed a synchronous rectification advance on-time control for PFM control, which can help address the ZVS at the lagging leg when the phase-shift angle is excessive. Detailed analysis and design of this control method are also described. The performance evaluation of the proposed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter with hybrid control was finally realized under the following conditions: 3.75 kW, dc input voltage of 400 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DC</sub> , dc output voltage of 75–475 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DC</sub> , and maximum conversion efficiency around 97%.

Разработка генератора «белого» шума СВЧ диапазона в гибридном интегральном исполнении

The article considers a technique for developing white noise generators, which makes it possible to design “quasi-white” noise generators in the operating frequency range of C and X noise diodes with a minimum non-uniformity of the noise power spectral density and the maximum possible excess noise factor operating in a wide temperature range.

МЕТОДИ ТА ЗАСОБИ ВИЗНАЧЕННЯ ОБ'ЄКТІВ РАДІОТЕХНІЧНОЇ РОЗВІДКИ З ВИКОРИСТАННЯМ ТЕХНОЛОГІЙ МАШИННОГО НАВЧАННЯ ТА ОНТОЛОГІЧНОГО ПІДХОДУ

The article is devoted to the study of methods and means of determining objects of radio technical intelligence using machine learning technologies and an ontological approach. A naіve Bayesian classifier was used to identify objects of radio technical intelligence. The Naive Bayes classifier is a machine learning algorithm used to classify objects based on probabilities. In this article, a naive Bayesian classifier is used to determine the classes to which objects of radio technical intelligence belong. The classifier uses historical data on object properties to determine the probability that each object belongs to a certain class. For example, based on the properties of the operating frequency range, pulse duration, pulse repetition period, and the number of sources of radio emissions, it is possible to determine the probability that the object belongs to a certain class of radio-technical intelligence. An ontological approach was used to specify the classes to which the objects of radio technical intelligence belong. The ontological approach is used to define classes of objects of radio technical intelligence in order to create a clear and unambiguous model of the subject area. This allows you to structure knowledge about objects, their properties, and relationships, which simplifies further data analysis and allows more accurate classification of new objects. The process of classifying objects in the military field, namely radio-technical intelligence, has been improved by combining the methods of k-nearest neighbors, the naive Bayesian classifier, and the ontological approach, which, unlike the existing methods, before applying the classifier, clustering of objects is carried out in order to take into account the ranges within which features of objects are defined. The analysis of input features showed that the main features for determining the means of radio technical intelligence are: “range of working frequencies”; “impulse duration”; “pulse repetition period”; “the number of sources of radio emissions”. An information system for the classification of radio-technical intelligence tools has been developed, the central component of which is the ontology of radio-technical intelligence tools. Simulation modeling of the work of the developed methods and algorithms was carried out. The choice of software tools for the implementation of the developed methods with the aim of further implementation on various platforms is substantiated. The JavaScript programming language using the JQuery library was used to implement the functional content of the system. The conducted simulation shows a satisfactory result of the developed methods and algorithms.

A Notch-Band UWB Antenna for OAM Wave Generation

This paper investigates a trapezoidal Monopole Patch Antenna (MPA) with an Ultra-Wideband (UWB) characteristic and a dual-stage notched band at fifth generation (5G) and Wireless Local-Area Network (WLAN) bands. The 5G band is notched by inserting a U-shaped slot on the trapezoidal UWB MPA. The WLAN band is notched using five-square metallic-conductor Electromagnetic Bandgap (EBG) patches that are installed on the surface of the backside of the radiating patch and attached to the ground plane via a shorting pin. The small, proposed antenna is built upon an FR4 substrate substance, having dielectric comparative permittivity εr = 4.7, and fed by a 50 Ω coplanar waveguide. The antenna’s size is 32×42.90×0.8 mm3. The simulated results show that the antenna has an operating frequency range of 2.39–14.72 GHz for |S11|&lt;-10 rejecting WLAN (5.15–5.825 GHz), as well as sub-6 GHz 5G (3.4–3.9 GHz) great-selectivity signals. A higher gain obtained by the UWB antenna is 6.4 dBi, while a sharp decrease occurs in the rejected bands, reaching -8.29 dBi. This study also employs the Orbital Angular Momentum (OAM) technique. However, OAM waves are generated using eight trapezoidal UWB MPAs. Creating notches reduces the interference problem in UWB frequencies, and merging the UWB with the OAM technique allows the OAM to operate on many frequencies. Moreover, notches can be generated for specific frequencies inside the UWB bands. These techniques, trapezoidal UWB MPA and OAM wave generation, can significantly increase the spectrum range and improve the spectrum efficiency in wireless communications.

Compact design of monopole antenna for SWB application with high BDR

AbstractIn this paper, a simple and compact monopole antenna with a high bandwidth ratio (BDR) of around is investigated for super wideband (SWB) applications. Using an F4B substrate with a dielectric constant of 2.65, loss tangent of 0.002, and connecting it to a triangular tapered 50‐Ohm line, the suggested antenna achieves its performance objectives. The proposed antenna has an electrical dimension of 0.14λ × 0.22λ and spans the SWB frequency range of 2.89–60 GHz with a 181.5% fractional bandwidth and reflection coefficient S11 &lt; −10 dB. It has been revealed that the results of both experiments and simulations are remarkably similar to one another in terms of their conclusions. In comparison to other SWB antennas, the suggested antenna has a greater BDR, a larger bandwidth, and a more compact size. Apart from that, the antenna has good gain and good radiation characteristics over the whole operational frequency range.

A novel active tendon pendulum tuned mass damper and its application in transient vibration control

Enhancing the performance characteristics of Tuned Mass Dampers (TMDs), in particular extending their narrow frequency band of operation, has been the subject of many researches. In the adaptive type of TMDs, the device's properties can be adjusted gradually in response to a slight alteration in the excitation characteristics and physical properties of the main structure. A novel vibration absorbing system, namely Active Tendon Pendulum TMD (AT-PTMD), is proposed in the present study. The device consists of a simple pendulum whose horizontal movement is restricted by a tendon with an adjustable tensile force which is attached to the pendulum’s rod. The device is designed and formulated, and its efficiency is assessed numerically and experimentally. For this purpose, a 3-degree of freedom structure is considered. Scrutinizing the responses of the uncontrolled, passively controlled and actively controlled structure shows the appropriate performance of the AT-PTMD in comparison with the passive TMD system in transient vibration reduction, particularly in reducing the total vibrational energy of the structure's response. Considering the achieved results, the proposed AT-PTMD system is capable of reducing the maximum displacement and acceleration of the main structure up to 43% and 37%, respectively, which substantiates its excellence over the common passive vibration absorbing devices. The case study also proves that the utilized mechanism for adjusting the equivalent stiffness of AT-PTMD increases its operating frequency range by 105% compared to common TMDs. Unlike active structural control systems, the suggested approach will not induce structural instability in any operating mode.

Design and Optimization of High-Power and Low-Frequency Broadband Transducer with Giant Magnetostrictive Material.

The applications of sensors in the aerospace industry are mostly concentrated in the middle and high frequencies, and low-frequency sensors often face the problems of low power and short working bandwidth. A lightweight, thin, high-power, low-frequency broadband transducer based on giant magnetostrictive material is designed. The design and optimization processes of the core components are introduced and analyzed emphatically. The finite element simulation results are validated by the PSV-100 laser vibration meter. Three basic configurations of the work panel are proposed, and the optimal configuration is determined by modal, acoustic, and vibration coupling analyses. Compared with the original configuration, it is found that the lowest resonant frequency of the optimal configuration is reduced by 24.6% and the highest resonant frequency within 2000 Hz is 1744.9 Hz, which is 54.2% higher than that of the original configuration. This greatly improves the vibration power and operating frequency range of the transducer. Then, the honeycomb structure is innovatively applied to the work panel, and it is verified that the honeycomb structure has a great effect on the vibration performance of the work panel. By optimizing the size of the honeycomb structure, it is determined that the honeycomb structure can improve the vibration power of the work panel to its maximum value when the distance between the half-opposite sides of the hexagon is H = 3.5 mm. It can reduce the resonant frequency of the work panel; the lowest resonant frequency is reduced by 12.8%. At the same time, the application of a honeycomb panel structure can reduce the weight of the transducer.

A multi-degree-of-freedom triboelectric energy harvester for dual-frequency vibration energy harvesting

Vibrational energy harvesting based on triboelectric transduction has been proven to be a cost-effective solution for powering small electronic sensors. Triboelectric energy harvesters (TEHs) that work in the contact-separation mode have been widely investigated with beam-mass structures. However, most beam-based TEHs utilize cantilever beams as their driving component, which is applicable only when its first mode is excited because higher modal frequencies are usually beyond the range of ambient vibrations. This study presents a novel contact-separation-mode energy harvester that, for the first time, combines triboelectric transduction with a multi-degree-of-freedom (MDOF) L-shaped beam-mass structure to harvest vibration energy at two operating frequencies. The TEH proposed in this study has two operating frequencies under 20 Hz and thus possesses an increased operating frequency range. A fully coupled electromechanical model that combines an MDOF distributed-parameter mechanical model with an electrical model for the TEH is derived. Experiments are then carried out to validate the model, characterize the performance of the TEH, and investigate the effect of the MDOF beam-mass structure on the contact-separation-mode TEH. It is shown that the predictions of the electromechanical model have an overall good agreement with the experimental results. Besides, the TEH can achieve a maximum root-mean-square voltage of 9.45 V when the first mode is excited and 11.56 V when the second mode is excited, given a base excitation acceleration of 0.6 g and the external load resistance of 1 MΩ. An optimal power of 300 μW is realized when the external load is 85 MΩ.

An Adaptive Control of Remote Hybrid Microgrid based on the CMPN Algorithm

• The paper proposes a decentralized droop-based control technique power flow through the ILC, meanwhile, to keep the dc microgrid voltage and the ac microgrid frequency within their acceptable ranges. • To overcome the continuous operation of ILC, The modified droop control based CMPN algorithm is used to determine the necessity of operation of hybrid microgrid by estimating the status of the ac and dc microgrids by comparing local measurements with their critical values at both sides. • An adaptive filtering algorithm based on continuous mixed P-norm (CMPN) algorithm is utilized for the proposed autonomous control strategy to insure adaptive tuning of the controller parameters. The variable step size feature of the CMPN algorithm results in fast response compared to other techniques such as robust mixed-norm and the least absolute deviation techniques. The robustness against impulsive noise while having fast convergence, compared to other algorithms, render the CMPN algorithm to be an effective technique for online adaptation of the PI controller used for the ILC, especially in an islanded archetype to maintain the stability of the network. • A comparison between the proposed strategy based on both CMPN algorithm and adaptive PI control under different loading conditions are implemented to validate the proposed methodology. This paper proposes a new adaptive communication-less control strategy to enhance the dynamic performance of the interlinking converter (ILC) of a remote hybrid microgrid. The proposed autonomous strategy is based on the continuous mixed P-norm (CMPN) algorithm to simultaneously maintain the frequency of ac-side and the voltage of dc-side of the ILC within their acceptable ranges under various conditions. The variable step nature of the CMPN algorithm and robustness ensure stable operation of the proposed strategy for the ILC. In addition, the power sharing between both sides of the ILC is achieved by a modified ac-dc droop control to avoid using any communication systems between different distributed generators (DG). Moreover, a simple algorithm is used to determine the desired power flow direction based on local measurements of dc voltage and frequency. The proposed CMPN algorithm provides an online adaption of the controller's parameters to avoid the need for fine tuning or optimization techniques under various operating conditions. The dynamic performance of the proposed autonomous control strategy is evaluated using the PSCAD/EMTDC simulation package under different operating modes. The results demonstrate the superior dynamic performance of the proposed strategy based on the CMPN algorithm compared to the adaptive PI (API) controller in terms of fast response and tight regulation of power flow, voltage and frequency under different conditions. Compared to API, it has been found that the proposed controller results in more improvement of the dc-side voltage within the operating frequency range of the ac-side of the ILC.

Identification of temperature-dependent elastic and damping parameters of carbon–epoxy composite plates based on experimental modal data

High-strength composite materials are receiving increased attention within the aerospace and transportation industries. These materials, although light in weight, still impart high stiffness when compared to conventional structural materials, e.g., aluminum and steel. Fibers and matrix are the basic constituents of composite materials. During high-speed maneuvering of aircraft and high-speed trains, the composite materials are subjected to dynamic loads in changing temperatures. The dynamic behavior of composites strongly depends on the ambient thermal environment. Furthermore, during the in-situ operation, the quantification of real-time dynamic loads is a challenging task. Therefore, the experimental investigation of the dynamic behavior of several carbon-fiber epoxy laminated composite plates at different temperatures, namely 0°C, 25°C, 50°C, 75°C, 100°C, and 125°C, is carried out using operational modal analysis, to identify the modal characteristics of the structure, and the temperature-dependent modal data of the tested composite plates is given in the supplementary data. The temperature-dependent elastic and damping parameters of the carbon–epoxy laminate are estimated using a genetic algorithm-based parameter identification scheme for different sets of modal contribution. A combined experimental and numerical simulation procedure is implemented to estimate deterministic material parameters at different temperatures. To obtain the in-situ material parameters for a given operating frequency range, the modal contribution is selected such that the operating frequency of interest lies within the considered resonance modes. As an example of matrix-dominated elastic parameter, the shear modulus, has been found to degrade significantly with increasing temperature, and shown a strong correlation with temperature.

Ground-Penetrating Radar Full-Wave Inversion for Soil Moisture Mapping in Trench-Hill Potato Fields for Precise Irrigation

In this paper, we analysed the effect of trench-hill soil surface on ground-penetrating radar (GPR) full-wave inversion for soil moisture measurement. We conducted numerical experiments by modelling the trench-hill surface using finite-difference time–domain (FDTD) simulations. The FDTD simulations were carried out with the open-source software gprMax, using different centre frequencies, namely, 150 MHz, 250 MHz and 450 MHz. The gprMax source/receiver for each centre frequency was calibrated, respectively, to transform the FDTD radar signal to normalized Green’s functions for wave propagation in multilayered media. The radar signals and inversion results of the three different frequency ranges are compared. The FDTD Green’s functions of the trench-hill surface with a flat surface are also compared. The results show that the trench-hill surface only slightly affects the inversion when frequency is lower than 190 MHz, which agrees with Rayleigh’s criterion. Field measurements were performed as well, using a prototype radar mounted on an irrigation robot. The low-frequency antenna was calibrated over a large water plane. The optimal operating frequency range was set to 130–190 MHz. TDR measurements were performed as well for comparison. The results demonstrated promising perspectives for automated and real-time determination of the root–zone soil moisture in potato fields, and thereby for precise and automatic irrigation.

Active control of human-induced vibrations on lightweight structures via electrodynamic actuator dynamics inversion

The active vibration absorber represents an effective means to mitigate excessive vibrations in low-damping structures. Nevertheless, the dynamics of the actuators employed in such systems may negatively affect their performance and stability restricting their operational frequency range. This article presents an application of dynamics inversion techniques to the force control of electrodynamic proof-mass actuators employed as active vibration absorbers in lightweight pedestrian structures. The dynamics inversion approach is applied to enhance the classical direct velocity feedback scheme. Additionally, a novel method relying on dynamics inversion is presented: the Broadband Force Cancellation Algorithm. This procedure consists in estimating, in real-time, the equivalent force acting on the system to later apply it back to the structure with the opposed sign. The effectiveness of the proposed methods is assessed via numerical simulations carried over a realistic model of an existing lightweight footbridge and an electrodynamic proof-mass actuator. Two load cases are analyzed: a fixed swept-sine force and a walking load. Both cases account for the actuator-structure interaction. The human-structure interaction is considered in the latter scenario due to its importance when dealing with lightweight pedestrian structures. Simulation results demonstrate that the dynamics inversion techniques effectively cancel out actuator dynamics leading to an excellent tracking of the reference force output by the suggested or other vibration control algorithm. The proposed schemes are proved promising since they substantially outperform the widespread direct velocity feedback approach. In particular, the Broadband Force Cancellation Algorithm minimizes the action of the external forces within their estimation frequency range, thus being especially suited to tackle broadband excitations, important in lively pedestrian structures, whereas the velocity feedback methodology performs best at the structural resonant frequencies.

Miniaturized Vivaldi Tapered Slot Antenna (VTSA) with Microstrip to SIW Feed Structure for X Band Application

Vivaldi tapered slot antenna (VTSA) families are low-cost, lightweight, and have a simple design structure with good electrical performance and consistent impedance over a wide frequency range. It can be fabricated on a fragile substrate to be used for various applications like an aircraft wing or in wearable networks. One biggest issue with this antenna is impedance matching. In this design, an antipodal Tapered slot antenna is used. The proposed antenna’s feed structure used a SIW (Substrate Integrated Waveguide) to microstrip transition. It allows us to design the characteristics of an antenna on a common substrate while maintaining a high-quality factor. The structure is simulated in CSTMWS (CST Microwave Studio) and the equivalent circuit of the transition part is also evaluated using ADS software tools. The operating frequency range of the structure is between 8 and 12 GHz (X band). This band has potential uses in radar, imaging, medical, space communication, and military applications. The whole structure is fabricated on the RO4003c substrate and measurements are taken with a VNA. The simulated and measured results are found to be very close to each other. The designed structure has a 40% percentage bandwidth and the overall dimension is 33 × 14 mm2.

New FTFN-Based Tunable Memristor Emulator Circuit and its Mutation to Meminductor and Memcapacitor Emulators

For the first time, a new memristor emulator structure using a single four-terminal floating nullor (FTFN) and a transconductance stage has been presented with tunable circuit configuration. Along with that the circuit requires only a single grounded capacitance and two external MOS transistors to realize both incremental and decremental types of memductance functions. The use of the FTFN block has been demonstrated for the first time to build such a compact memristor emulator, which fully utilizes the employed circuit resources. The wide-band operating frequency range (1 kHz–3 MHz) is another attractive feature of the proposed emulator. Moreover, the mutation of the proposed memristor emulator into meminductor and memcapacitor emulators is also presented by the mutators based on FTFN. All the presented circuits have been tested by performing simulations using PSPICE with 0.18-[Formula: see text]m CMOS technology. The generated simulation results clearly show the ideal nonvolatile nature of the realized memristor, which has also been utilized in an op-amp-based circuit designed to exhibit associative learning phenomena. The proposed FTFN-based memristor has been implemented using commercially available ICs, LM13700, and AD844, and the generated PHL plot is discussed.

Design of a novel 5G MIMO antenna with its DGP optimisation using PSOGSA

ABSTRACT In this manuscript, the design of a high isolation Multiple Input Multiple Output (MIMO) Hybrid Fractal Antenna (HFA) has been presented for 5 G and other wireless standards in a wider operational frequency range from 1 to 30 GHz. The fractional ground plane is used for the assembly of the antenna in the initial phase, further, the T-stub has been exploited on the ground plane to expand the isolation between the radiating elements. The dimensions of the proposed antenna are optimised using the Particle Swarm Optimisation Gravitational Search Algorithm (PSOGSA). The performance parameters of the projected antenna have been measured and analysed. The obtained experimental results are highly correlated with simulated ones. Performance diversity parameters of designed antenna like CCL, DG, ECC, TARC, and MEG fall within working limits in the frequency range of interest. The developed antenna retains high isolation between −30 to−50 dB in the desired frequency range. The proposed model of an antenna can be useful for 5 G 3.5 GHz band, 5 G NR (New Radio) frequency bands (3.3–5.0 GHz), LTE band 46 (5.15–5.925 GHz), European Union 5 G frequency band (5.9–6.4 GHz), 5 G 26 GHz frequency band and other wireless standards in the frequency range from 1 to 30 GHz.

FSS embedded high gain ‘N’ shaped miniaturized broadband antenna

This research work represents a broadband (3.3 GHz − 17.85 GHz) high gain miniaturized (16 mm × 24 mm × 1.6 mm) microstrip patch antenna. Initially multiband property is achieved through ‘N’ shaped radiating patch surface and ‘I’ shaped ground plane surface. Finally broadband property is attained through better impedance matching by modifying feeding structure with a single step matching staircase structure. The presented antenna shows large −10 dB impedance bandwidth of 14.55 GHz with a percentage bandwidth of 138 %, Bandwidth Dimension Ratio (BDR) of 2970 and a peak gain of 4.45 dBi at 9.5 GHz. By embedding FSS (Frequency Selective Surface) structure having FSS unit cell dimension of 13 mm × 13 mm × 1.6 mm with the antenna at suitable distance, antenna gain has been elevated successfully across the entire operating frequency range (3.25 GHz–17.8 GHz). FSS coupled antenna exhibits highest gain improvement of 7.5 dBi at 3.5 GHz and peak gain of 9.1 dBi at 9.3 GHz. The FSS integrated antenna structure operates with elevated gain (peak gain of 9.1 dBi at 9.3 GHz) across the entire operating frequency range (3.25 GHz–17.8 GHz). All inclusive volume of the presented FSS coupled antenna is 52 mm × 52 mm × 21.2 mm, which can be successfully utilized in high gain broadband wireless applications. The antenna patch area miniaturization is calculated as 65 % with respect to lowest frequency of operation. The proposed FSS and antenna are developed and simulated by utilizing CST Studio Suite Software and equivalent circuit of the presented antenna is simulated utilizing ADS software. Both FSS and antenna are fabricated using inexpensive FR 4 substrate (1.6 mm thick, relative dielectric constant of 4.4 and loss tangent of 0.02) and Standard Microwave Test Bench is used to validate the antenna and composite antenna structure simulation results.

Voltage-controlled topological interface states for bending waves in soft dielectric phononic crystal plates

The operating frequency range of passive topological phononic crystals is generally fixed and narrow, limiting their practical applications. To overcome this difficulty, here we design and investigate a one-dimensional soft dielectric phononic crystal (PC) plate system with actively tunable topological interface states via the mechanical and electric loads. We use nonlinear electroelasticity theory and linearized incremental theory to derive the governing equations. First we determine the nonlinear static response of the soft dielectric PC plate subjected to a combination of axial force and electric voltage. Then we study the motion of superimposed incremental bending waves. By adopting the Spectral Element Method, we obtain the dispersion relation for the infinite PC plate and the transmission coefficient for the finite PC plate waveguide. Numerical results show that the low-frequency topological interface state exists at the interface of the finite phononic plate waveguide with two topologically different elements. By simply adjusting the axial force or the electric voltage, an increase or decrease in the frequency of the topological interface state can be realized. Furthermore, applying the electric voltage separately on different elements of the PC plate waveguide is a flexible and smart method to tune the topological interface state in a wide range. These results provide guidance for designing soft smart wave devices with low-frequency tunable topological interface states.