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Article
Publication date: 6 December 2022

Pallav Rawal and Sanyog Rawat

In wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is…

Abstract

Purpose

In wireless communication system, use of multiple antennas for different requirements of system will increase the system complexity. However, reconfigurable antenna is maximizing the connectivity to cover different wireless services that operate different frequency range. Pattern reconfigurable antenna can improve security, avoid noise and save energy. Due to their compactness and better performance at different applications, reconfigurable antennas are very popular among the researchers. The purpose of this work, is to propose a novel design of S-shaped antenna with frequency and pattern diversity. The pattern and frequency reconfiguration are controlled via ON/OFF states of the PIN diode.

Design/methodology/approach

The geometrical structure of the proposed antenna dimension is 18 × 18 × 0.787 mm3 with εr = 2.2 dielectric constant. Three S-shaped patches are connected to a ring patch through PIN diodes. The approximate circumference of ring patch is 18.84 mm and length of patch is 5 mm, so approximate length of radiating patch is 14.42 mm and effective dielectric constant is 1.93. Conductor backed coplanar waveguide (CPW) is used for feeding. The proposed antenna is designed and simulated on CST microwave studio and fabricated using photolithography process. Measurements have been done in anechoic chamber.

Findings

Antenna shows the dual band operation at 2.1 and 3.4 GHz frequency. The first band remains constant at 2.1 GHz resonant frequency and 200–400 MHz impedance bandwidth. Second band is switched at seven different resonant frequencies as 3.14, 3.45, 3.46, 3.68, 3.69, 3.83 and 3.86 GHz with switching of the diodes. The −10 dB bandwidth is more than 1.4 GHz.

Research limitations/implications

Pattern reconfigurability can be achieved using mechanical movement of antenna easily but it is not a reliable approach for planar antennas. Electronic switching method is used in proposed antenna. Antenna size is very small so fabrication is very crucial task. Measured results are deviated from simulation results due to fabrication error and effect of leads of diodes, connecting wires and battery.

Practical implications

The reconfiguration of the proposed antenna is controlled via ON/OFF states of the three PIN diodes. The lower band of 2.1 GHz is fixed, while second band is switched at five different resonant frequencies as 3.27, 3.41, 3.45, 3.55 and 3.88 GHz, with switching of the PIN diodes with all state of diodes and exhibit pattern reconfigurability at 2.1 GHz frequency. At second band center frequency is significantly changed with state of diodes and at 3.4 GHz pattern is also changed with state of diodes, hence antenna exhibits frequency and pattern reconfigurability.

Originality/value

A novel design of pattern and frequency reconfigurable antenna is proposed. Here, work is divided into two parts: first is frequency reconfiguration and second is radiation pattern reconfiguration. PIN diodes as switch are used to select the frequency band and reconfigure the radiation pattern. This proposed antenna design is novel dual band frequency and pattern reconfigurable antenna. It resonates at two distinct frequencies, i.e. 2.1 and 3.4 GHz, and has a pattern tilt from 0° to 355°. The conductor backed CPW feed technique is used for impedance matching.

Details

Microelectronics International, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1356-5362

Keywords

Open Access
Article
Publication date: 15 November 2022

Liyao Song, Bai Chen, Bo Li, Rupeng Zhu and Dan Wang

The supercritical design of tail rotor drive shaft has attracted more attention in helicopter design due to its high power–weight ratio and low maintenance cost. However…

Abstract

Purpose

The supercritical design of tail rotor drive shaft has attracted more attention in helicopter design due to its high power–weight ratio and low maintenance cost. However, there exists excessive vibration when the shaft passes through the critical frequency. Dry friction damper is the equipment applied to the drive shaft to suppress the excessive vibration. In order to figure out the damping mechanism of the dry friction damper and improve the damping efficiency, the dynamic model of the shaft/damper system is established based on the Jeffcott rotor model.

Design/methodology/approach

The typical frequency response of the system is studied through bifurcation diagrams, amplitude-frequency characteristic curves and waterfall frequency response spectrum. The typical transient responses under frequency sweeps are also obtained.

Findings

The results show that the response of the system changes from periodic no-rub motion to quasi-periodic rub-impact motion, and then to synchronous full annular rub-impact, and finally, back to periodic no-rub motion. The slip of the rub-impact ring improves the stability of the system. Besides, the effects of the system parameters including critical dry friction force, rub-impact friction coefficient, initial clearance on the stability and the vibration damping capacity are studied. It is observed that the stability changes significantly varying the three parameters respectively. The vibration damping capacity is mainly affected by the critical dry friction force and the initial clearance.

Originality/value

Presented results provide guidance for the design of the dry friction damper.

Details

Journal of Intelligent Manufacturing and Special Equipment, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2633-6596

Keywords

Article
Publication date: 15 September 2022

Parul Trivedi and B.B. Tiwari

The primary aim of this paper is to present a novel design approach for a ring voltage-controlled oscillator (VCO) suitable for L-band applications, whose oscillation…

Abstract

Purpose

The primary aim of this paper is to present a novel design approach for a ring voltage-controlled oscillator (VCO) suitable for L-band applications, whose oscillation frequency is less sensitive to power supply variations. In a few decades, with the advancement of modern wireless communication equipment, there has been an increasing demand for low-power and robust communication systems for longer battery life. A sudden drop in power significantly affects the performance of the VCO. Supply insensitive circuit design is the backbone of uninterrupted VCO performance. Because of their important roles in a variety of applications, VCOs and phase locked loops (PLLs) have been the subject of significant research for decades. For a few decades, the VCO has been one of the major components used to provide a local frequency signal to the PLL.

Design/methodology/approach

First, this paper chose to present recent developments on implemented techniques of ring VCO design for various applications. A complementary metal oxide semiconductor (CMOS)-based supply compensation technique is presented, which aims to reduce the change in oscillation frequency with the supply. The proposed circuit is designed and simulated on Cadence Virtuoso in 0.18 µm CMOS process under 1.8 V power supply. Active differential configuration with a cross-coupled NMOS structure is designed, which eliminates losses and negates supply noise. The proposed VCO is designed for excellent performance in many areas, including the L-band microwave frequency range, supply sensitivity, occupied area, power consumption and phase noise.

Findings

This work provides the complete design aspect of a novel ring VCO design for the L-band frequency range, low phase noise, low occupied area and low power applications. The maximum value of the supply sensitivity for the proposed ring VCO is 1.31, which is achieved by changing the VDD by ±0.5%. A tuning frequency range of 1.47–1.81 GHz is achieved, which falls within the L-band frequency range. This frequency range is achieved by varying the control voltage from 0.0 to 0.8 V, which shows that the proposed ring VCO is also suitable for low voltage regions. The total power consumed by the proposed ring VCO is 14.70 mW, a remarkably low value using this large transistor count. The achievable value of phase noise is −88.76 dBc/Hz @ 1 MHz offset frequency, which is a relatively small value. The performance of the proposed ring VCO is also evaluated by the figure of merit, achieving −163.13 dBc/Hz, which assures the specificity of the proposed design. The process and temperature variation simulations also validate the proposed design. The proposed oscillator occupied an extremely small area of only 0.00019 mm2 compared to contemporary designs.

Originality/value

The proposed CMOS-based supply compensation method is a unique design with the size and other parameters of the components used. All the data and results obtained show its originality in comparison with other designs. The obtained results are preserved to the fullest extent.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 14 September 2022

Chengsi Huang, Zhichao Yang and Jiedong Li

Due to the advantages of fast response, high positioning precision and large stiffness, the piezoelectric-actuated nanopositioning stage is widely used in the…

Abstract

Purpose

Due to the advantages of fast response, high positioning precision and large stiffness, the piezoelectric-actuated nanopositioning stage is widely used in the micro/nanomachining fields. However, due to the inherent nonlinear hysteresis of the piezoelectric-actuator, the positioning accuracy of nanopositioning stage is greatly degraded. Besides, the nanopositioning stage is always performed with repetitive trajectories as the reference signals in applications, which makes the hysteresis behavior periodic. To this end, an adaptive resonance suppression iterative learning control (ARS-ILC) is proposed to address the hysteresis effect. With this effort, the positioning accuracy of the nanopositioning stage is improved.

Design/methodology/approach

The hysteresis behavior is identified by the Prandtl–Ishlinskii model. By establishing a convergence function, it is demonstrated that the learnable band of ILC is restricted by the lightly damping resonance of nanopositioning stage. Then, an adaptive notch filter (ANF) with constrained poles and zeros is adopted to suppress the resonant peak. Finally, online stability supervision (OSS) is used to ensure that the estimated frequency converges to the resonant frequency.

Findings

A series of experiments were carried out in the nanopositioning stage, and the results validated that the OSS is available to ensure the convergence of the ANF. Furthermore, the learnable band was extended via ARS-ILC; thus, the hysteresis behavior of nanopositioning stage has been canceled.

Originality/value

Due to high accuracy and easy implementation, the ARS-ILC can be used in not only nanopositioning stage control but other fabrication process control with repetitive motion.

Details

Assembly Automation, vol. 42 no. 5
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 28 September 2010

Mohammad Asaduzzaman Chowdhury

The purpose of this paper is to investigate experimentally the effect of natural frequency of the experimental set‐up on wear rate of glass fiber‐reinforced plastic (GFRP).

263

Abstract

Purpose

The purpose of this paper is to investigate experimentally the effect of natural frequency of the experimental set‐up on wear rate of glass fiber‐reinforced plastic (GFRP).

Design/methodology/approach

Experimental and dimensional analysis. A pin‐on‐disc apparatus having facility of vibrating the test samples at different directions, amplitudes and frequencies was designed and fabricated. The natural frequency of the set‐up was varied by adding dead loads of the set‐up from 0 to 50 kg. At each added load, the wear rate has been measured.

Findings

The presence of natural frequency of vibration indeed affects the wear rate considerably. The values of wear rate increase with the increase of natural frequency of vibration of the experimental set‐up. As the wear rate increases with increasing natural frequency of vibration, therefore, maintaining appropriate level of natural frequency vibration wear may be kept to some lower value to improve mechanical processes. The empirical formula of wear rate is derived from the dimensionless analysis. The wear rate obtained from the correlation shows better relationship with experimental results.

Practical implications

It is expected that the applications of these results will contribute to the improvement of different concerned mechanical systems and machines.

Originality/value

Considering the lack of correlation among wear rate, natural frequency of the experimental set‐up and other operating parameters, the present research was started to find out suitable correlation and a way of reducing wear rate by applying known natural frequency of vibration at a particular direction. Therefore, in this paper, an attempt is made to investigate the wear behavior of GFRP under natural frequency of the experimental set‐up. It is expected that the applications of these results will contribute to the improvement of different concerned mechanical systems.

Details

Industrial Lubrication and Tribology, vol. 62 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 June 2003

Mayela Zamora, Manus Henry and Christian Peter

The use of frequency output for measurement transmission remains common in the design of smart transmitters. Conventional methods of frequency generation, based on…

Abstract

The use of frequency output for measurement transmission remains common in the design of smart transmitters. Conventional methods of frequency generation, based on counting clock cycles, have a precision which is inversely proportional to the frequency to be generated. Consequently, frequency output precision could be much lower than the measurement precision. This paper describes a simple frequency generation technique which, when implemented in low‐cost hardware, provides a precision of 10−6 per cent for all frequencies. The method represents an intermediate non‐available frequency by dithering between two exact frequencies. Averaging over some reasonably short timescale provides the desired frequency to high precision.

Details

Sensor Review, vol. 23 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 9 January 2007

Fatma Ben Salem and Ahmed Masmoudi

This paper aims to discuss a comprehensive analysis of the effects of torque and flux hysteresis bands on the inverter average switching frequency considering an induction…

Abstract

Purpose

This paper aims to discuss a comprehensive analysis of the effects of torque and flux hysteresis bands on the inverter average switching frequency considering an induction machine drive under the control of the Takahashi DTC strategy.

Design/methodology/approach

The analysis of the effects of torque and flux hysteresis bands on the inverter average switching frequency is carried out taking into account the speed range and the sampling period.

Findings

It has been found that the inverter average switching frequency could be more or less taken down according to the speed range and the sampling period by selecting suitable flux and torque hysteresis bands.

Research limitations/implications

This work should be extended by an experimental validation of the established results.

Practical implications

The reduction of the inverter switching frequency is of great importance in direct torque controlled induction motor drive as far as it leads to a decrease of the torque ripple and an increase of the efficiency.

Originality/value

For given torque and flux hysteresis bands, the inverter average switching frequency presents nonlinear shape. Given the fact that the flux switching frequency is a linear function of the speed, one can conclude that the nonlinearity of the inverter average switching frequency is due to the torque switching frequency. This statement has been proven by the introduction of the so‐called focal speeds for the torque switching frequency turns to be null.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 29 March 2011

Kirubakaran Dhandapani and Rama Reddy Sathi

The purpose of this paper is to present, a novel boost‐active clamp bridge single stage high‐frequency zero voltage soft‐switching‐pulse width modulation (ZVS‐PWM…

Abstract

Purpose

The purpose of this paper is to present, a novel boost‐active clamp bridge single stage high‐frequency zero voltage soft‐switching‐pulse width modulation (ZVS‐PWM) inverter, which converts the utility frequency AC power into high‐frequency AC power with an embedded controller. This single stage high‐frequency inverter is composed of a single‐phase diode bridge rectifier, a non‐smoothing filter, a boost‐active clamp bridge type ZVS‐PWM high‐frequency inverter, and an induction‐heated load with planar type litz wire working coil assembly. Also, the paper discusses how to extend the soft‐switching operation ranges and improve power conversion efficiency.

Design/methodology/approach

The proposed converter is simulated and it is implemented using embedded controller.

Findings

It was found that the single stage high‐frequency induction heating (IH) inverter using boosted voltage function can eliminate the DC and low‐frequency components of the working coil current and reduce the power dissipation of the circuit components and switching devices.

Originality/value

The paper shows that the PWM HF inverter is preferred for IH, since it has reduced switching losses and switching stresses. The paper can be extended to PC‐based wireless control, which can be part of a distributed control system in major industrial heating systems.

Details

Journal of Engineering, Design and Technology, vol. 9 no. 1
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 29 April 2014

Michał Lewandowski and Janusz Walczak

A highly accurate method of current spectrum estimation of a nonlinear load is presented in this paper. Using the method makes it possible to evaluate the current…

Abstract

Purpose

A highly accurate method of current spectrum estimation of a nonlinear load is presented in this paper. Using the method makes it possible to evaluate the current injection frequency domain model of a nonlinear load from previously recorded time domain voltage and current waveforms. The paper aims to discuss these issues.

Design/methodology/approach

The method incorporates the idea of coherent resampling (resampling synchronously with the base frequency of the signal) followed by the discrete Fourier transform (DFT) to obtain the frequency spectrum. When DFT is applied to a synchronously resampled signal, the spectrum is free of negative DFT effects (the spectrum leakage, for example). However, to resample the signal correctly it is necessary to know its base frequency with high accuracy. To estimate the base frequency, the first-order Prony's frequency estimator was used.

Findings

It has been shown that the presented method may lead to superior results in comparison with window interpolated Fourier transform and time-domain quasi-synchronous sampling algorithms.

Research limitations/implications

The method was designed for steady-state analysis in the frequency domain. The voltage and current waveforms across load terminals should be recorded simultaneously to allow correct voltage/current phase shift estimation.

Practical implications

The proposed method can be used in case when the frequency domain model of a nonlinear load is desired and the voltage and current waveforms recorded across load terminals are available. The method leads to correct results even when the voltage/current sampling frequency has not been synchronized with the base frequency of the signal. It can be used for off-line frequency model estimation as well as in real-time DSP systems to restore coherent sampling of the analysed signals.

Originality/value

The method proposed in the paper allows to estimate a nonlinear load frequency domain model from current and voltage waveforms with higher accuracy than other competitive methods, while at the same time its simplicity and computational efficiency is retained.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 33 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2005

Sergey Y. Yurish, Nikolay V. Kirianaki and Ramon Pallàs‐Areny

To provide detailed information about the novel universal frequency‐to‐digital converter UFDC‐1, which can help engineers and researchers to design new digital sensors and…

Abstract

Purpose

To provide detailed information about the novel universal frequency‐to‐digital converter UFDC‐1, which can help engineers and researchers to design new digital sensors and transducers, as well as smart sensors and sensor systems.

Design/methodology/approach

The high performance of the UFDC‐1 is achieved by using four novel measuring methods for frequency‐time parameters. All existing integrated frequency‐to‐digital converters and frequency (time) output sensors have been reviewed and current design requirements for the UFDC‐1 have been formulated.

Findings

The UFDC‐1 enables the transition from traditional analog (voltage and current) sensors output to frequency‐time output. This yields a lot of benefits due to the properties of frequency as informative parameter. No output standardization is necessary, as opposed to the case of analog output sensors. Users can now work with the UFDC‐1, the same as with traditional ADCs. Sensor manufacturers can simply integrate the UFDC‐1 in microsystems and digital output sensors in order to produce serial output or bus capability.

Practical implications

The UFDC‐1 has many applications: obtaining a digital output from any frequency, period, duty‐cycle, time interval, phase‐shift, pulse number output sensors, up to one chip digital sensors design and smart (self‐adaptive) sensors, thanks to its programmable relative error and non‐redundant conversion time. The UFDC‐1 can work with any existing frequency‐time domain sensor to produce a digital output or create multiparametric smart sensors and systems.

Originality/value

This paper fulfils an identified information need and offers practical help to engineers and researchers in designing new digital sensors and transducers, as well as smart sensors and systems using a minimum of hardware.

Details

Sensor Review, vol. 25 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

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