A Fully Electronic Time Reversal Mirror System Based on Temporal Imaging

Zhao, Xiaoxiang; Xiao, Shaoqiu; Sun, Ying

doi:10.1109/access.2019.2894763

Cited by 4 publications

(2 citation statements)

References 26 publications

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“…In the proposed method, the TRM plays three roles [37], [38]: (1) collecting the incident Bessel beam information, (2) realizing the TR operation of the collected electric field information, and (3) transmitting the inverse field.…”

Section: B Time-reversal Bessel Beam Synthesis Methodsmentioning

confidence: 99%

Synthesis of Bessel Beam Using Time-Reversal Method Incorporating Metasurface

et al. 2021

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In this paper, a synthesis and implementation method for generating Bessel beams based on time-reversal theory incorporating electromagnetic (EM) meta-lens is proposed. As is known, time-reversal EM waves has the unique characteristic of adaptive backtracking. Therefore, with this characteristic, the EM characteristics of the radiation aperture can be obtained and further utilized to generate Bessel waves with any departure angle. Based on this concept, two meta-lenses for generating Bessel beams tilted in different directions were designed. Both meta-lenses were designed at the center frequency of 15 GHz, and the simulation results were consistent with the target expectation. A representative meta-lens was fabricated and measured. The final size of the meta-lens was 350 mm × 350 mm, and a Bessel beam with a 30° emergence angle was generated by this structure. The experimental results were in good agreement with the simulation results and the theoretical derivation. This synthetic method of Bessel beam generation using the time-reversal operation may be of great use for the application of Bessel beams in microwave communications, and it can broaden the application scope of non-diffracting beams.

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Section: B Time-reversal Bessel Beam Synthesis Methodsmentioning

confidence: 99%

Synthesis of Bessel Beam Using Time-Reversal Method Incorporating Metasurface

et al. 2021

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“…According to the time-reversal process shown in Fig.3, the damage-related wave can be focused back on the scattering target that acts as acoustic sources. Here we take the pitch-catch array (as shown in Fig.1) as an example to detail this process [66], [67]. As shown in Fig.1, the signal received at the crack due to an input signal at PZT A can be represented by…”

Section: ) Principle Of News-trmentioning

confidence: 99%

Detection of Surface Breaking Cracks Filled With Solid Impurities Using a Baseline-Free NEWS-TR Method

Qin

Zhang

et al. 2020

IEEE Access

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The use of piezoceramic transducers for cracks identification via guided wave has attracted significant attention recently. Most studies assume that the medium in surface breaking cracks is only air. However, it is common that such cracks are filled with impurities (e.g. dust, grease) due to its exposure to the operational environment. The impurities may affect the propagation of the ultrasonic guided wave and hence it is of practical interest to develop detection methods for surface breaking cracks filled with impurities. This work investigates the possible effect of contact acoustic nonlinearity (CAN) on detecting surface breaking cracks filled with solid impurities. A baseline-free method is proposed to detect surface breaking cracks filled with solid impurities using the nonlinear elastic wave spectroscopy (NEWS) as a pre-treatment of time-reversal (TR). This method involves three key issues: selecting low-frequency swept signal modulated by Hanning window as an excitation signal, comparing the initial filtered response with the nonlinear time reversal response to determine the nonlinear feature related to such cracks, and determining the recommended low cutoff frequency to extract such nonlinear feature. The feasibility of the proposed method is experimentally and numerically verified using aluminum beams with surface breaking cracks. Results show that due to the existence of solid impurities, the crack interacts with low-frequency ultrasonic waves, which leads to nonlinear components in the response signal. It also indicates that after the time-reversal processing, the shifting of the maximum peak frequency from the second harmonic range to the third harmonic range can be used as a damage-sensitive nonlinear feature for detecting such cracks. The proposed method provides a promising way to identify surface breaking cracks filled with solid impurities without reference signal. INDEX TERMS Baseline-free damage detection, contact acoustic nonlinearity (CAN), nonlinear elastic wave spectroscopy (NEWS), piezoelectric transducers, surface breaking cracks filled with solid impurities, structural health monitoring (SHM), time reversal (TR). GUOMING CHEN received the B.S. and M.S. degrees in petroleum mechanical engineering and the Ph.D. degree in mechanical design and theory from the

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Time-Varying Planar Structure for Time Reversal of Microwave Signal

Sun

Cheng

2021

2021 International Conference on Microwave and Millimeter Wave Technology (ICMMT)

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A Fully Electronic Time Reversal Mirror System Based on Temporal Imaging

Cited by 4 publications

References 26 publications

Synthesis of Bessel Beam Using Time-Reversal Method Incorporating Metasurface

Synthesis of Bessel Beam Using Time-Reversal Method Incorporating Metasurface

Detection of Surface Breaking Cracks Filled With Solid Impurities Using a Baseline-Free NEWS-TR Method

Time-Varying Planar Structure for Time Reversal of Microwave Signal

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