To circumvent the issue of significant space occupation associated with omnidirectional antenna-based rectennas and to seamlessly integrate into self-powered applications with minimal uncovered zones, this paper prese...
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To circumvent the issue of significant space occupation associated with omnidirectional antenna-based rectennas and to seamlessly integrate into self-powered applications with minimal uncovered zones, this paper presents a new flat-panel rectenna (FPR) designed specifically for microwave-based wireless power charged sensor applications. This innovation aims to optimize space efficiency and enhance energy capture capabilities, providing a more effective solution for the continuous and reliable operation of wireless powered devices in various sectors. The proposed compact rectenna is designed with a planar antenna featuring wide beamwidth and an RF-to-DC conversion network that includes a dual-voltage rectifier architecture and a customized matching network to optimize RF-to-DC conversion efficiency. The FPR is then integrated with a batteryless heart rate sensor, enabling the sensor to operate and expand its physical orientation while maintaining accurate monitoring. The performance of the proposed RF energy harvester was evaluated at 5.8 GHz, showing a half-power coverage of 144.6 degrees with respect to a peak antenna gain of 3.34 dBi, and a peak RF-to-DC conversion efficiency of 51.8%. Additionally, the batteryless sensor was shown to function effectively with a maximum RF energy incident angle of 140 degrees, despite the flat-panel architecture.
The rapid proliferation of Internet of Things (IoT) devices and applications has led to an increasing demand for energy-efficient and secure communication in wirelesssensornetworks. In this article, we firstly propo...
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The rapid proliferation of Internet of Things (IoT) devices and applications has led to an increasing demand for energy-efficient and secure communication in wirelesssensornetworks. In this article, we firstly propose an intelligent approach to maximize the energy efficiency of the UAV in a secure sensornetwork with wireless power transfer (WPT). All sensors harvest energy via downlink signal and use it to transmit uplink information to the UAV. To ensure secure data transmission, the UAV needs to optimize the transmission parameters to decode received information under malicious interference from an attacker. Code Division Multiple Access (CDMA) is adopted to improve uplink communication robustness. To maximize the UAV's energy efficiency in data collection tasks, we formulate a constrained optimization problem that jointly optimizes charging power, charging duration, and data transmission duration. Applying Deep Deterministic Policy Gradient (DDPG) algorithm, we train an action policy to dynamically determine near-optimal transmission parameters in real time. Numerical results validate the superiority of proposed intelligent approach over exhaustive search and gradient ascent techniques. This work provides some important guidelines for the design of green secure wireless-powered sensornetworks.
Integrated Sensing and communication (ISAC) involves incorporating wireless sensing capabilities into communication systems. The integration of ISAC affords improvements in the performance of the communication system,...
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Integrated Sensing and communication (ISAC) involves incorporating wireless sensing capabilities into communication systems. The integration of ISAC affords improvements in the performance of the communication system, as well as the ability to perform high-precision motion detection, positioning, imaging, and other related functions. Therefore, it is highly valuable to develop an ISAC terminal device that has a high degree of integration and energy efficiency. Here, we propose an ISAC chip that utilizes the coexistence of luminescence and detection properties of III-nitride multiple quantum wells for motion detection and visible light communication. The ISAC chip includes both a transmitter and a receiver of visible light and is fabricated on a sapphire wafer with InGaN/GaN multiple quantum wells. A rotating mirror is used as the object for motion detection and modulates the light signal emitted by the transmitter in a reflected light path. The variation period of the photocurrent curve generated by the modulated light signal is consistent with the rotation period of the mirror. We also investigate the performance of this chip as a transmitter and transceiver terminal of visible light communication systems. The results of the study provide a promising approach for the integration of motion sensing and visible light communication. [GRAPHICS]
Orbital angular momentum(OAM)holography has become a promising technique in information encryption,data storage and opto-electronic computing,owing to the infinite topological charge of one single OAM mode and the ort...
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Orbital angular momentum(OAM)holography has become a promising technique in information encryption,data storage and opto-electronic computing,owing to the infinite topological charge of one single OAM mode and the orthogonality of different OAM *** this paper,we propose a novel OAM hologram generation method based on a densely connected U-net(DCU),where the densely connected convolution blocks(DCB)replace the convolution blocks of the ***,the reconstruction process of the OAM hologram is integrated into DCU as its output layer,so as to eliminate the requirement to prepare training data for the OAM hologram,which is required by conventional neural networks through an iterative *** experimental and simulation results show that the OAM hologram can rapidly be generated with the well-trained DCU,and the reconstructed image's quality from the generated OAM hologram is significantly improved in comparison with those from the Gerchberg-Saxton generation method,the Gerchberg-Saxton based generation method and the U-net *** addition,a 10-bit OAM multiplexing hologram scheme is numerically demonstrated to have a high capacity with OAM hologram.
It is difficult to improve both energy consumption and detection accuracy simultaneously,and even to obtain the trade-off between them,when detecting and tracking moving targets,especially for Underwater wireless Sens...
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It is difficult to improve both energy consumption and detection accuracy simultaneously,and even to obtain the trade-off between them,when detecting and tracking moving targets,especially for Underwater wirelesssensornetworks(UWSNs).To this end,this paper investigates the relationship between the Degree of Target Change(DoTC)and the detection period,as well as the impact of individual nodes.A Hierarchical Detection and Tracking Approach(HDTA)is ***,the network detection period is determined according to DoTC,which reflects the variation of target ***,during the network detection period,each detection node calculates its own node detection period based on the detection mutual *** DoTC as pheromone,an ant colony algorithm is proposed to adaptively adjust the network detection *** simulation results show that the proposed HDTA with the optimizations of network level and node level significantly improves the detection accuracy by 25%and the network energy consumption by 10%simultaneously,compared to the traditional adaptive period detection schemes.
This letter presents a design methodology for implementing broadband load-modulated balanced amplifier (LMBA) for handset applications. It is evaluated which architecture, Doherty-like LMBA (DL-LMBA) or pseudo-Doherty...
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This letter presents a design methodology for implementing broadband load-modulated balanced amplifier (LMBA) for handset applications. It is evaluated which architecture, Doherty-like LMBA (DL-LMBA) or pseudo-Doherty LMBA (PD-LMBA), is more suitable for InGaP/GaAs HBT power amplifier (PA). The impedance transformation ratio (ITR) is optimized through an analysis of correlation between the coupler impedance (Z(0)) and matching network (MN). A prototype LMBA attains measured saturation power (P-SAT), collector efficiency (CE), and 6-dB output power back-off (OBO) CE of over 33.2 dBm, 45.2%, and 42.0%, respectively, in the range of 3.2-5.0 GHz. The LMBA is also evaluated by 5G NR FR1 100-MHz QPSK CP-OFDM with 9.5-dB peak-to-average power ratio (PAPR), achieving 26.6-dBm average output power (P-avg) with 37.7% average CE (CEavg) at an adjacent channel leakage ratio (ACLR) of -33 dBc.
A network of wirelesssensors is a self-infrastructure approach with many sensory nodes. The distributed sensory nodes communicate with each other via sensory points. In wirelesssensornetwork (WSN), the sensory node...
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A network of wirelesssensors is a self-infrastructure approach with many sensory nodes. The distributed sensory nodes communicate with each other via sensory points. In wirelesssensornetwork (WSN), the sensory nodes collect information for healthcare, military and monitoring systems. Such networks require an exclusive arrangement of the nodes to challenge inherent limitations and energy deficiency. The conventional design of a communication system consumes more energy with high latency causing degraded performance. This study provided a machine learning-based path optimization mechanism using the least energy resources in designing an effective wirelessnetwork system with enhanced three measures of network performance, including throughput, packet delivery efficiency and energy usage. The proposed methodology is validated through network simulation tools.
The convergence of digital twin technology and the emerging 6G network presents both challenges and numerous research opportunities. This article explores the potential synergies between digital twin and 6G, highlight...
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The convergence of digital twin technology and the emerging 6G network presents both challenges and numerous research opportunities. This article explores the potential synergies between digital twin and 6G, highlighting the key challenges and proposing fundamental principles for their integration. We discuss the unique requirements and capabilities of digital twin in the context of 6G networks, such as sustainable deployment, realtime synchronization, seamless migration, predictive analytic, and closed-loop control. Furthermore, we identify research opportunities for leveraging digital twin and artificial intelligence to enhance various aspects of 6G, including network optimization, resource allocation, security, and intelligent service provisioning. This article aims to stimulate further research and innovation at the intersection of digital twin and 6G, paving the way for transformative applications and services in the future.
Traditional power transmission networks with complex physical wiring have struggled to meet the power needs of emerging portable and decentralized devices. Recently, rectified metasurfaces for electromagnetic (EM) ene...
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Traditional power transmission networks with complex physical wiring have struggled to meet the power needs of emerging portable and decentralized devices. Recently, rectified metasurfaces for electromagnetic (EM) energy harvesting have attracted great attention from researchers due to their customizability and application flexibility. However, many previous structures mainly focused on harvesting efficiency and ignored harvesting bandwidth. Here, we propose a broadband rectified metasurface structure for radar frequency band EM energy harvesting and wireless power transfer. The cell structure consists of a centrosymmetric hyperbolic ring (CHR) structure that can exhibit an EM wave absorptivity of greater than 80 % at wide incidence angles. The AC energy of each cell is exported through metal vias, and the energy is pooled through the feed networks. Finally, the rectification circuit is designed to complete the AC-to-DC conversion and the DC energy harvesting. broadband EM energy harvester can be achieved when the incidence angle is 0(degrees) to 60(degrees) . The half-power bandwidth (HPBW) can be up to 55 % with a normal incidence. To verify the rectified metasurface function, a prototype with 6 x 6 metasurface array is fabricated and tested. When the rectified metasurface operates at 6.1 GHz, RF-to-DC energy harvesting efficiency of greater than 35 % can be achieved in the incidence angle range of 0(degrees) to 60(degrees) and maximum efficiency is 57 %. It makes it possible to self-power sensornetwork nodes working in the vicinity of communication base stations or radar base stations.
This article presents and investigates a V -band transmitter (TX) for low-power wirelesscommunication supporting on-off keying (OOK) and four-/eight-level pulse amplitude modulation (PAM4/8). To prove the concept, th...
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This article presents and investigates a V -band transmitter (TX) for low-power wirelesscommunication supporting on-off keying (OOK) and four-/eight-level pulse amplitude modulation (PAM4/8). To prove the concept, the circuit is implemented in a 22-nm fully depleted silicon-on-insulator (FD-SOI) complementary metal oxide semiconductor (CMOS) technology. The TX consumes 11.7 mW at full speed. Furthermore, the TX supports low-power mode with as low as 700 nW of dc power. The maximum data rate is 2 Gb/s. By applying dynamic data rate to dc-power adaptivity (DDDA), the dc power can be significantly reduced as the data rates decreases. This maintains the energy-per-bit below 10 pJ/b for data rates greater than 100 kb/s with a best value of 3.9 pJ/b and allows the dc power to be greatly reduced down to 700 nW at data rates below 20 kb/s. The measured maximum transmission power is 6.5 dBm. Moreover, the TX achieves 10-dBm effective isotropic radiated power (EIRP) with an on-chip 3-D antenna. The core area of the TX is only 0.19 mm 2 . To the best knowledge of the authors, the proposed TX is the first reported TX with DDDA and achieves the lowest dc power in comparison to similar designs that have been reported to date.
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