The use of fractional derivation in modeling ferroelectric dynamic hysteresis behavior over large frequency bandwidth

Person identification plays a critical role in a large range of applications. Recently, RF based person identification becomes a hot research topic due to the contact-free nature of RF sensing that is particularly appealing in current COVID-19 pandemic. However, existing systems still have multiple limitations: i) heavily rely on the gait patterns of users for identification; ii) require a large amount of data to train the model and also extensive retraining for new users and iii) require a large frequency bandwidth which is not available on most commodity RF devices for static person identification. This paper proposes RF-Identity, an RFID-based identification system to address the above limitations and the contribution is threefold. First, by integrating walking pattern features with unique body shape features (e.g., height), RF-Identity achieves a high accuracy in person identification. Second, RF-Identity develops a data augmentation scheme to expand the size of the training data set, thus reducing the human effort in data collection. Third, RF-Identity utilizes the tag diversity in spatial domain to identify static users without a need of large frequency bandwidth. Extensive experiments show an identification accuracy of 94.2% and 95.9% for 50 dynamic and static users, respectively.

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Path Tracking Design by Fractional Prefilter Extension to Square MIMO Systems

Volume 4: 7th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, Parts A, B and C ◽

10.1115/detc2009-87550 ◽

2009 ◽

Cited By ~ 4

Author(s):

P. Melchior ◽

C. Inarn ◽

A. Oustaloup

Keyword(s):

Mimo Systems ◽

Path Tracking ◽

Multivariable Systems ◽

Frequency Bandwidth ◽

Control Loop ◽

Physical Constraints ◽

Performance Specifications ◽

Fractional Derivation ◽

Synthesis Methodology ◽

Robust Synthesis

The aim of this paper concerns motion control and robust path tracking. An approach based on fractional prefilter synthesis was already developed. It allows tracking optimization according to the fractional derivation order, the actuators physical constraints and the control loop frequency bandwidth. The purpose of this paper is the extension of this approach to multivariable systems. A non integer prefilter synthesis methodology for square MIMO systems (Multi-Input, Multi-Output) is presented. It is based on the MIMO-QFT robust synthesis methodology, taking into account of the plant uncertainties. MIMO-QFT robust synthesis methodology is based on multiple SISO (MISO systems) synthesis by considering the loop couplings. The SISO-QFT synthesis methodology can be then used for each SISO synthesis. Then the prefilters are synthesized. The prefilter parameter optimization is founded on the prefilter output error integral minimization, taking into account of the actuators physical constraints and the tracking performance specifications. An application example is given.

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Design and Modeling of New UWB Metamaterial Planar Cavity Antennas with Shrinking of the Physical Size for Modern Transceivers

International Journal of Antennas and Propagation ◽

10.1155/2013/562538 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 9

Author(s):

Mohammad Alibakhshi Kenari

Keyword(s):

Transmission Lines ◽

Patch Antenna ◽

Patch Antennas ◽

Frequency Bandwidth ◽

Left Handed ◽

Full Wave ◽

Radiation Properties ◽

Unit Cells ◽

Constitutive Parameters ◽

Large Frequency

A variety of antennas have been engineered with MTMs and MTM-inspired constructs to improve their performance characteristics. This report describes the theory of MTMs and its utilization for antenna's techniques. The design and modeling of two MTM structures withε-μconstitutive parameters for patch antennas are presented. The framework presents two novel ultrawideband (UWB) shrinking patch antennas filled with composite right-/left-handed transmission line (CRLH-TL) structures. The CRLH-TL is presented as a general TL possessing both left-handed (LH) and right-handed (RH) natures. The CRLH-TL structures enhance left-handed (LH) characteristics which enable size reduction and large frequency bandwidth. The large frequency bandwidth and good radiation properties can be obtained by adjusting the dimensions of the patches and CRLH-TL structures. This contribution demonstrates the possibility of reducing the size of planar antennas by using LH-transmission lines. Two different types of radiators are investigated—a planar patch antenna composed of fourO-formed unit cells and a planar patch antenna composed of sixO-shaped unit cells. A CRLH-TL model is employed to design and compare these two approaches and their realization with a varying number ofL-Cloaded unit cells. Two representative antenna configurations have been selected and subsequently optimized with full-wave electromagnetic analysis. Return loss and radiation pattern simulations of these antennas prove the developed concept.

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Influence of various sintering parameters and the temperature dependent scaling on the dynamic hysteresis behavior of Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 ceramics

Multidiscipline Modeling in Materials and Structures ◽

10.1108/mmms-10-2019-0185 ◽

2020 ◽

Vol 17 (1) ◽

pp. 273-290

Author(s):

P. Suresh ◽

P. Mathiyalagan ◽

K.S. Srikanth

Keyword(s):

Electric Field ◽

Coercive Field ◽

Remnant Polarization ◽

Sintering Temperature ◽

Scaling Relations ◽

Temperature Dependent ◽

Content Type ◽

Hysteresis Behavior ◽

Dynamic Hysteresis ◽

Ferroelectric Hysteresis

PurposeThe article explores the effect of sintering temperature on the ferroelectric hysteresis behavior of the synthesized ceramic material Ba0.9Ca0.05Sr0.05T0.85Zr0.15O3 (BCSTZO). It describes how the sintering temperature and its holding time have effect on the polarization-electric field (P-E) loops which is an important characteristic of a ferroelectric material. From the P-E loops obtained, various representative parameters like remnant polarization and coercive field values were extracted and scaling results were systematically established using them.Design/methodology/approachThe present article describes the establishment of scaling relations for coercive field (Ec), remnant polarization (Pr) and back switching polarization (Pbc) as a function of temperature which have been obtained from P-E loops sintered at various temperature and time. This is because sintering temperature plays a pivotal role in determining the hysteresis parameters.FindingsThe temperature dependent scaling of Ec and Pr at sintering temperature of 1400, 1425, 1450 and 1475 °C yields EcαT0.40, EcαT0.80, EcαT0.47, EcαT0.29 and PrαT−1.72, PrαT−1.55, PrαT−1.72, PrαT−1.69 respectively. Further the scaling relations for the samples sintered at 1450 °C at different time interval of 3, 4, 5 and 6 h was also established to bring the effect of sintering in switching the ferroelectric hysteresis parameters.Originality/valueThe findings of this work will prove beneficial for the researchers working in optimization of sintering parameters and will benefit researchers selecting best material among the fabricated samples for further property enhancement. The optimized sample could be explored for multifunctional applications ranging from pyroelectric voltage to piezoelectric energy harvesting. In addition to this, the scaling results help to understand the nature of ferroelectric parameters with sintering. This may open up new avenues for studying the scaling behavior of dynamic hysteresis in synthesized material by focusing on hysteresis area as a function of applied electric fields, frequency and temperature. This reason owes to the fact that electric field and frequency are important parameters for a number of applications like sensor, transducers and medical applications.

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