Ultrasensitive, Parity–Time-Symmetric Wireless Reactive and Resistive Sensors

Sakhdari, Maryam; Hajizadegan, Mehdi; Li, Yue; Cheng, Mark Ming Cheng; Hung, Jonathan C. H.; Chen, Pai‐Yen

doi:10.1109/jsen.2018.2870322

Cited by 64 publications

(36 citation statements)

References 45 publications

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“…We note that such a dark-mode behavior is not found in the standard PT-symmetric system [ Fig. 2(b)] whose eigenfrequencies are always a strong function of κ and γ [25][26][27][28][29][30][31]52].…”

Section: Higher-order Pt-symmetric Wireless Poweringmentioning

confidence: 88%

“…Counterintuitively, if a quantum system is invariant under the combined action of space inversion (P ) and time reversal (T), it exhibits either entirely real eigenspectra or complex conjugate eigenvalue pairs. Although PT-symmetry was originally considered as one of interesting theoretical findings in quantum physics, it has been experimentally demonstrated in opti-cal [36,37], acoustic [38] and electronic [25][26][27][28][29][30][31][32][33][34] platforms, and has aroused intense interest for real-life applications, such as lasers [39][40][41], sensors [28][29][30][31][32][42][43][44][45][46], cloaks [47,48], and nonreciprocal devices [49]. In electronics, the lumpedelement circuitry could be the simplest possible configuration for observation of exotic physics of PT-symmetric Hamiltonian [30].…”

Section: Higher-order Pt-symmetric Wireless Poweringmentioning

confidence: 99%

“…In the Hamiltonian analysis for the PT circuit, since an RF source is represented by -Z 0 (gain), the transmitter can be seen as an -RLC resonator. If the load impedance is greater (smaller) than Z 0 , a negative resistance element [28,29] (resistor) must be used. As shown in Fig.…”

Section: Experimental Demonstration Of Wpt System With Third-ordmentioning

confidence: 99%

“…However, in the standard (second-order) PT-symmetric electronic systems [25][26][27][28][29][30][31][32][33][34], the exact PT-symmetric phase requires a moderately strong coupling strength [25,28], and this makes the system fail to maintain a satisfactory efficiency at weak/loose coupling (e.g., midrange power transfer). In addition, perturbing the load resistance of receiver could lead to a symmetry-breaking phase transition [29,34] and a low efficiency is obtained in such broken PT-symmetric phases.…”

Section: Introductionmentioning

confidence: 99%

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Robust extended-range wireless power transfer using a higher-order PT-symmetric platform

Sakhdari

Hajizadegan

Chen

2020

Phys. Rev. Research

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A fundamental challenge for the nonradiative wireless power transfer (WPT) resides in maintaining the stable power transmission with a consistently high efficiency under dynamic conditions. Here, we propose and experimentally demonstrate that a frequency-locked WPT system satisfying the higher-order parity-time (PT) symmetry can achieve a near-unity power transfer efficiency that is resilient to effects of distance variation and misalignment between coils, and impedance fluctuations in electric grids. In specific higher-order PT electronic systems, a purely real-valued and coupling-invariant (nonbifurcated) eigenfrequency would enable the robust and efficient wireless charging without frequency hopping or adaptive impedance matching, even for midrange operation. We envision that this WPT technique may provide reliable, fast and efficient power delivery for a variety of consumer electronics, electric vehicles, and medical devices.

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Section: Higher-order Pt-symmetric Wireless Poweringmentioning

confidence: 88%

Section: Higher-order Pt-symmetric Wireless Poweringmentioning

confidence: 99%

Section: Experimental Demonstration Of Wpt System With Third-ordmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Robust extended-range wireless power transfer using a higher-order PT-symmetric platform

Sakhdari

Hajizadegan

Chen

2020

Phys. Rev. Research

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“…The image compression technology in the past decade has revolutionized the field of data communication. Today's high-definition photograph accessing/editing, live video display and multimedia messaging are easy and instantaneous because of compression techniques [1,2]. The compression technique helps in representing the source image with a reduced number of bits.…”

Section: Introductionmentioning

confidence: 99%

A lossless image compression algorithm using wavelets and fractional Fourier transform

Kumar

Jagadale

Bhat³

2019

SN Appl. Sci.

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The necessity of data transfer at a high speed, in fast-growing information technology, depends on compression algorithms. Maintaining quality of data reconstructed at high compression rate is a very difficult part of the data compression technique. In this paper, a new lossless image compression algorithm is proposed, which uses both wavelet and fractional transforms for image compression. Even though wavelets are the best choice for feature extraction from the source image at different frequency resolutions, the low-frequency sub-bands of wavelet decomposition are the untouched part in compression method in most of the existing methods. On the other hand, fractional Fourier transform is a convenient form of generalized Fourier transform that helps in the compact lossless coding of the source image with optimal fractional orders. Hence, we have used discrete fractional Fourier transform to compress those sensitive sub-bands of the wavelet transform, carefully. In this method, an image is split into low-and high-frequency sub-bands by using Daubechies wavelet filter and level 1 quantization is applied for both low-frequency and high-frequency subbands. The low-frequency sub-bands are compressed by using fractional Fourier transform with optimal fractional orders, and at the same time, high-frequency sub-bands are compressed by eliminating zeroes and storing only nonzero blocks and its position. The compressed wavelet coefficients are further compressed by the application of level 2 quantization and stored as a reduced array. This reduced array is encoded by using arithmetic encoder followed by run-length coding. The experimental results of the proposed algorithm with a different set of test images are compared with some of the existing image compression algorithms. The results show that the proposed method has significant improvement in image reconstruction quality.

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