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On secrecy outage probability for downlink NOMA systems with relay-antenna selection

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Research Square

Research Square 2021年

作者： Xu, Shu Liu, Chen Wang, Hong Qian, Mujun Sun, Wenfeng National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology Nanjing University of Posts and Telecommunications No.9 Wenyuan Road Qixia District Nanjing210003 China School of Science and Information Qingdao Agricultural University Qingdao266109 China

Secure transmission is essential for future non-orthogonal multiple access (NOMA) system. This paper investigates relay-antenna selection (RAS) to enhance physical-layer security (PLS) of cooperative NOMA system in the presence of an eavesdropper, where multiple antennas are deployed at the relays, the users, and the eavesdropper. In order to reduce expense on radio frequency (rf) chains, selection combining (SC) is employed at both the relays and the users, whilst the eavesdropper employs either maximal-ratio combining (MRC) or selection combining (SC) to process the received signals. Under the condition that the channel state information (CSI) of the eavesdropping channel is available or unavailable, two effective relay-antenna selection schemes are proposed. Additionally, the closed-form expressions of secrecy outage probability (SOP) are derived for the proposed relay-antenna selection schemes. In order to gain more deep insights on the derived results, the asymptotic performance of the derived SOP is analyzed. In simulations, it is demonstrated that the theoretical results match well with the simulation results and the SOP of the proposed schemes is less than that of the conventional orthogonal multiple access (OMA) scheme obviously. © 2021, CC BY.

关键词： Channel state information

High Sensitivity and Ultrahigh Eqe (1040.13%) Ga2o3 Ultraviolet Photodetector by One-Step Thermal Oxidation of P-Gan Films

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SSRN 2022年

作者： Wang, Jinjin Ji, Xueqiang Yan, Xu Lu, Chao Li, Zhitong Qi, Song Yan, Zuyong Li, Shan Qi, Xiaohui Zhang, Sai Hu, Shengrun Li, Peigang School of Integrated Circuits State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing100876 China College of Integrated Circuit Science and Engineering National and Local Joint Engineering Laboratory for RF Integration and Micro-Packaging Technologies Nanjing University of Posts and Telecommunications Nanjing210023 China

In this study, the Ga 2 O 3 thin films were successfully prepared by one-step thermal oxidation of p-GaN thin films, which were oxidized at 900 °C with varying oxidation times in the environment with argon-oxygen ratio of 1000. The effect of different oxidation durations on the physical properties of the Ga 2 O 3 thin films was studied, and particularly, the photoelectric performance of the Ga 2 O 3 thin films was further analyzed. The Ga 2 O 3 thin film thermally oxidized for 2 h has a single crystallographic orientation and excellent photoelectric performance. Compared with the GaN thin film, the dark current of the photodetector was approximately reduced by 2.31 × 10 4 times while the photocurrents of the device maintain the same order of magnitude, causing a large photo-to-dark current ratios (PDCRs) of 2.29 × 10 4 . The device exhibits impressive characteristics such as high responsivity of 2.13 A/W, super high external quantum efficiency (EQE) of 1040.13%, large detectivity (D*) of 1.65×10 11 Jones, and fast response speed of 0.218/0.112 s under UV light illumination of 254 nm wavelength at -5 V bias. The results indicate that the device can be used as a good candidate for high sensitivity, fast response and the high-resolution detection. © 2022, The Authors. All rights reserved.

关键词： Thin films

Mxene/Biomass/Chitosan Carbon Aerogel (Mbc) with Shared Cathode and Anode for the Construction of High-Efficiency Asymmetric Supercapacitor

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SSRN 2023年

作者： Zhang, Shaohui Cui, Yinhua Shi, Qingshan Liu, Zeng Lv, Jingchun Wang, Chao Xie, Xiaobao State Key Laboratory of Applied Microbiology Southern China Institute of Microbiology Guangdong Academy of Sciences Guangzhou510070 China Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronic Engineering College of Mechatronics and Control Engineering Shenzhen University Shenzhen518060 China School of Chemistry and Pharmaceutical Engineering Shandong First Medical University Shandong Academy of Medical Sciences Tai’an271016 China College of Integrated Circuit Science and Engineering & National and Local Joint Engineering Laboratory for RF Integration and Micro-Packing Technologies Nanjing University of Posts and Telecommunications Nanjing210023 China College of Textiles and Clothing Yancheng Institute of Technology Yancheng224051 China

Despite the rapid development of biomass-based carbon aerogel research and specific outcomes have been accomplished, the preparation process requires to be developed further compared with other porous media such as activated carbon and graphene, and there are still many obstacles to overcome before reaching industrial production and practical applications since the competitiveness in terms of mechanical strength, adsorption capacity, and structural stability is weaker. Via using electro-static self-assembly between the negatively charged MXene nanosheets and the positively charged radish flakes infiltrated with salt solution, a strategy is proposed for the in-situ preparation of flexible MXene/biomass/chitosan aerogel (MBC) pseudo-capacitive electrode by hydrothermal methods. The electrode was drived according to the principle of concentration difference permeation (CDP) between MXene nanosheets and radish cells. Under both driving forces, the MXene nanosheets are embedded inside the radish cells. Importantly, the MBC pseudocapacitive electrode doping 6% (MBC-6) by lyophilization annealing exhibits a volumetric specific capacitance of 1801.4 mF/cm3 at a scan rate of 2 mV/s. In addition, the assembled binder-free asymmetrical supercapacitor exhibits an ultra-high volume energy density of 33.4 Wh/L, a capacitance retention rate of 82% and a long cycle life of 50000 times at a high current density of 10 mA/cm3. A plausible approach for creating energy storage devices with a high energy density and voltage window is presented in this study. © 2023, The Authors. All rights reserved.

关键词： Stability

High Sensitivity Ga2O3 Ultraviolet Photodetector by One-Step Thermal Oxidation of P-GaN Films

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SSRN 2022年

作者： Li, Peigang Wang, Jinjin Ji, Xueqiang Yan, Zuyong Yan, Xu Li, Zhitong Lu, Chao Qi, Song Li, Shan Qi, Xiaohui Zhang, Sai Hu, Shengrun School of Integrated Circuits State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing100876 China School of Science Lanzhou University of Technology Lanzhou730050 China College of Integrated Circuit Science and Engineering National and Local Joint Engineering Laboratory for RF Integration and Micro-Packaging Technologies Nanjing University of Posts and Telecommunications Nanjing210023 China

Gallium oxide (Ga2O3), with an ultra-wide bandgap, is a promising semiconductor material for the manufacture of solar blind ultraviolet photodetectors. Herein, Ga2O3 thin films were successfully prepared by simpler feasible one-step thermal oxidation of p-GaN thin films, which were oxidized at 900 °C with varying oxidation times in the environment with argon-oxygen ratio of 1000. The effect of different oxidation durations on the physical properties of the Ga2O3 thin films was studied, and particularly, the photoelectric performance of the Ga2O3 thin films was further analyzed. The Ga2O3 thin film thermally oxidized for 2 h has a single crystallographic orientation and excellent photoelectric performance. Compared with the GaN thin film, the dark current of the photodetector was approximately reduced by 2.31 × 104 times while the photocurrents of the device maintain the same order of magnitude, causing a large photo-to-dark current ratios (PDCRs) of 2.29 × 104. Furthermore, the device exhibits impressive characteristics such as high responsivity of 2.13 A/W, super high external quantum efficiency (EQE) of 1040.13%, large detectivity (D) of 1.65×1011 Jones, and fast response speed of 0.218/0.112 s under UV light illumination of 254 nm wavelength at -5 V bias. The results indicate that the one-step thermal oxidation can be used as a good application for preparing the device with high sensitivity, fast response and the high-resolution detection. © 2022, The Authors. All rights reserved.

关键词： Thin films

Study on modulation bandwidth of GaN-based micro-light-emitting diodes by adjusting quantum well structure

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Research Square

Research Square 2022年

作者： Yin, Pan Zhi, Ting Tao, Tao Liu, Xiaoyan Institute for Electric Light Sources School of Information Science and Technology Fudan University Shanghai200433 China Key Laboratory of Advanced Photonic and Electronic Materials School of Electronic Science and Engineering Nanjing University Nanjing210046 China College of Integrated Circuit Science and Engineering National and Local Joint Engineering Laboratory for RF Integration and Micro-Packaging Technologies Nanjing University of Posts and Telecommunications Nanjing210023 China

GaN-based blue micro-light-emitting diodes (µ-LEDs) with different structures were designed, of which the effect of quantum well (QW) structure on modulation bandwidth was numerically explored. By using trapezoidal QWs, the quantum-confined Stark effect (QCSE) can be reduced, leading to an enhanced electron-hole wave function overlap, thereby increasing the recombination rate and reducing the differential carrier lifetime. In addition, the improved hole transport also creates favorable conditions for shortening the differential carrier lifetime. It is found that the − 3 dB modulation bandwidth of µ-LEDs with trapezoidal QWs was higher than those of ordinary ones. In this work, the − 3 dB modulation bandwidth of µ-LEDs can be raised to 1.13 GHz at 10 kA/cm2 © 2022, CC BY.

关键词： Light emitting diodes

The growth and expansive applications of amorphous Ga2O3

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Chinese Physics B 2023年第8期 70-86页

作者：奚昭颖杨莉莉舒林聪张茂林李山史丽刘增郭宇锋唐为华 Innovation Center for Gallium Oxide Semiconductor (IC-GAO) College of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications National and Local Joint Engineering Laboratory for RF Integration and Micro-Assembly Technologies Nanjing University of Posts and Telecommunications Key Laboratory for Organic Electronics and Information Displays (KLOEID) & Institute of Advanced Materials (IAM) Jiangsu Key Laboratory for Biosensors Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) Nanjing University of Posts and Telecommunications Key Laboratory of Aerospace Information Materials and Physics Nanjing University of Aeronautics and Astronautics Ministry of Industry and Information Technology

As a promising ultra-wide bandgap semiconductor material, gallium oxide（Ga2O3） is attracting extensive attention of researchers due to its feasible growth process, appropriate bandgap of 4.4 e V–5.3 e V allowing for deep-ultraviolet（deepUV） detection, good physical and chemical stability, high breakdown field strength and electron mobility, etc. Different from the strict processes for controllable crystalline Ga2O3（usually refer to as stable monoclinic β-Ga2O3）, amorphous Ga2O3（a-Ga2O3） film can be prepared uniformly at low temperature on a large-area deposition substrate, suggesting great advantages such as low manufacturing cost and excellent flexibility, dispensing with high-temperature and high vacuum techniques. Thus, a-Ga2O3extremely facilitates important applications in various applied fields. Therefore, in this concise review, we summarize several major deposition methods for a-Ga2O3films, of which the characteristics are ***, potential methods to optimize the film properties are proposed by right of the inspiration from some recent studies. Subsequently, the applications of a-Ga2O3thin films, e.g., in photodetectors, resistive random access memories（RRAMs） and gas sensors, are represented with a fruitful discussion of their structures and operating mechanisms.

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Design of Dual-band Implantable Antenna with Shorting Pins 8

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Design of Dual-band Implantable Antenna with Shorting Pins

8th Asia-Pacific Conference on Antennas and Propagation, APCAP 2019

作者： Hua, Dengyu Jin, Xiaoyu Xu, Li-Jie Duan, Zhu Nanjing University of Posts and Telecommunications National and Local Joint Engineering Laboratory of Rf Integration and Micro-Assembly Technology Nanjing China Southeast University State Key Laboratory of Millimeter Waves Nanjing China

ISBN: (纸本)9781665400541

This paper proposes a pin-loaded dual-band antenna for implantable applications, covering both 915 MHz Industrial, Scientific and Medical (ISM) band and 1.4 GHz Wireless Medical Telemetry Service (WMTS) band. With two shorting pins loaded at two corners, miniaturization is achieved. Furthermore, four straight slots are introduced on the top patch, giving rise to the appearance of two resonances for dual-band operation. To achieve better impedance matching, another three open-end L-shaped slots are etched on the ground, and the final proposed antenna is well matched at two required bands. © 2019 IEEE.

关键词： microwave antennas

A Spline-Profile Smooth-Walled Horn With Low Cross-Polarization And Low Sidelobe

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A Spline-Profile Smooth-Walled Horn With Low Cross-Polarizat...

International Conference on Smart Grid and Electrical Automation (ICSGEA)

作者： Zijing Wu Yaming Bo Shaohua Wu National and Local Joint Engineering Laboratory of RF Integration and Micro-Assembly Technology Nanjing University of Posts and Telecommunications Nanjing People's Republic of China Jangsu Food and Pharmaceutical Science College

ISBN: (数字)9781728182780

ISBN: (纸本)9781728182797

spline-profile smooth-walled horns are widely used as feeds for its symmetric beam, low cross-polarization levels and low sidelobes while their fabrication is easier than corrugated conical horns, especially at millimeter-wave frequencies. In this paper, a spline-profile smooth-walled horn, for a synthetic aperture, has been demonstrated with low cross-polarization (

关键词： Zirconium Xenon Smart grids Hafnium Automation

A Systematic Study on Electronic, Mechanical, and Thermal Transport Properties of Germanium Antimony Selenide Telluride Alloy by First-Principles Approach

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SSRN 2022年

作者： Lian, Xiaojuan Li, Fu Liu, Peng Wan, Xiang Liu, Xiaoyan Ren, Qingying Cai, Zhikuang Wang, Ning Wang, Lei College of Integrated Circuits Science and Engineering Nanjing University of Posts and Telecommunications NO. 9 Wenyuan Road Jiangsu Nanjing210023 China National and Local Joint Engineering Laboratory of RF Integration oand Micro-assembly Technology Nanjing University of Posts and Telecommunications NO. 9 Wenyuan Road Jiangsu Nanjing210023 China Electrical & Electronic Laboratory Center Department of Optical Engineering College of Electronic and Optical Engineering College of Microelectronics Nanjing University of Posts and Telecommunications NO. 9 Wenyuan Road Jiangsu Nanjing210023 China School of Science Key Laboratory of High Performance Scientific Computation Xihua University Chengdu610039 China

Ge2Sb2Se4Te alloy has most recently exhibited its outstanding optical properties for non-volatile photonic storage applications, while its electrical and thermal transport properties were rarely reported, thus limiting its application versatility. To overcome above issue, we performed detailed study on the electrical, mechanical and thermal transport properties of Ge2Sb2Se4Te alloy according to first-principles calculations. The calculated results showed that, originating from the layered crystal structure of Ge2Sb2Se4Te, its Young’s modulus and shear modulus along the in-plane direction were found to be larger than those along the out-of-plane direction, which suggested more superb anti-deformation characteristics along the in-plane direction. Besides, the calculated Poisson's ratio implied that the in-plane bonding of Ge2Sb2Se4Te was mainly ionic-covalent bonding, and the out-of-plane bonding was of van der Waals (vdW) interaction character. The huge chemical bond difference between in-plane direction and out-of-plane direction led to strong phonon anharmonicity and phonon thermal transport anisotropy. Therefore, layered Ge2Sb2Se4Te exhibited low phonon group velocity and short phonon lifetime, which led to encouragingly low lattice thermal conductivities of 4.45 W/mK, 3.54 W/mK and 0.41 W/mK along the x-axis, y-axis and z-axis at 300 K, respectively. Also, calculated electronic structure revealed the metallicity character of Ge2Sb2Se4Te alloy without pronounced band gap, which made this material applicable to thermal insulation materials rather than traditional thermoelectric materials. This work was useful to promote the application of Ge2Sb2Se4Te in the field of engineering thermal management and storage devices based on the optical-thermal mechanism. © 2022, The Authors. All rights reserved.

关键词： Van der Waals forces