Search | Engineering

Subscribe Submit

Home Journals Focus Achievement Fronts About Us 中文版

Resource Type

Journal Article 180

Year

2024 1

2023 22

2022 25

2021 21

2020 17

2019 10

2018 14

2017 16

2016 2

2015 1

2014 1

2012 4

2011 2

2010 2

2009 3

2008 4

2007 4

2006 4

2005 2

2004 3

open ︾

Keywords

Antenna array 3

Camera array 2

Colloids 2

Direction of arrival 2

Drug discovery 2

Grey wolf optimizer 2

OFDM 2

feed industry 2

natural frequency 2

1) 1

3D bioprinting 1

3D scaffold platform 1

4-Bit reconfigurable antenna array 1

5G 1

5G smartphone 1

60 GHz 1

AR model 1

Acoustic localization 1

Aerodynamics 1

open ︾

Search scope:

排序： Display mode:

Dot-shaped beamforming analysis of subarray-based sin-FDA Research Article

Bo Wang, Jun-wei Xie, Jing Zhang, Jia-ang Ge,wb_wangbo1991@163.com

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 10, Pages 1429-1444 doi: 10.1631/FITEE.1800722

Abstract: Phased array (PA) radar is one of the most popular types of radar. In contrast to PA, the (FDA) is a potential solution to suppress range-related interference because of its time-range-angle-dependent beampattern. However, the range-angle coupling inherent in the FDA transmit beampattern may degrade the output signal-to-interference-plus-noise ratio (SINR). We propose a method based on the analyzed four subarray-based FDAs and subarray-based planar FDAs using a sinusoidally increasing frequency offset with elements transmitting at multiple frequencies. The numerical results show that the proposed approach outperforms the existing log-FDA with logarithmical frequency offset in transmit energy focus, sidelobe suppression, and array resolution. Comparative simulation results validate the effectiveness of the proposed method.

Keywords：频率分集阵列；子阵频率分集阵列；解耦；点状波束形成

HTML PDF Collect

Deceptive jamming discrimination based on range-anglelocalization of a frequency diverse array Article

Zhao-jian ZHANG, Jun-wei XIE, Chuan SHENG, Zhun TANG

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 9, Pages 1437-1446 doi: 10.1631/FITEE.1601577

Abstract: We propose a method to suppress deceptive jamming by frequencydiverse array (FDA) in radar electronic countermeasure environments.FDA offers a new range-angle-dependent beam pattern through a smallfrequency increment across elements. Due to the coupling between theangle and range, a mismatch between the test angle and physical angleoccurs when the slant range on which the beam focuses is not equalto the slant range of the real target. In addition, the range of thetarget can be extracted by sum-difference beam except for time-delaytesting, because the beam provides a range resolution in the FDA thatcannot be deceived by traditional deceptive jamming. A strategy ofusing FDA to transmit two pulses with zero and nonzero frequency increments,respectively, is proposed to ensure that the angle of a target canbe obtained by FDA. Moreover, the localization performance is examinedby analyzing the Cramer-Rao lower bound and detection probability.Effectiveness of the proposed method is confirmed by simulation results.

Keywords： Frequency diverse array (FDA) Deceptive jamming Range-angle coupling Sum-difference beam Double-pulse

HTML PDF Collect

A novel wideband ring antenna for polarization/pattern diversity Correspondence

Li SUN, Shigang ZHOU, Guanxi ZHANG, Baohua SUN

Frontiers of Information Technology & Electronic Engineering 2022, Volume 23, Issue 6, Pages 975-983 doi: 10.1631/FITEE.2100421

Abstract:

We present a novel wideband ring antenna for polarization/pattern diversity. The proposed antenna consists of eight printed dipole elements in the form of a circular array. The arms of adjacent elements overlap for capacitive loading. Unlike traditional circular arrays, a method of exciting elements in the form of every two intervals is first introduced. We prove that this method can maintain the wideband characteristics of the antenna. Four independent feeding ports in a ring antenna aperture are designed for the polarization/pattern diversity with suitable feeding networks. As an example, a wideband dual-polarized antenna was designed based on the proposed ring antenna. To achieve two orthogonal linear polarizations with maximum radiation in the direction, two adjacent elements are extracted periodically to feed through one port. The differential feeding network and integrated Baluns have been designed to realize broadside radiation patterns, considering impedance and phase matching. Because the proposed antenna is hollow, it is a good candidate for a multiband sharing aperture antenna element. Results show that the proposed antenna has an overlapped bandwidth of 50.5% (1.04–1.82 GHz) with voltage standing wave ratio (VSWR)<2 for the two polarizations, and port isolation less than 23 dB. The measured realized gain ranges from 6.1 to 8.1 dBi, with stable broadside radiation patterns over the operating frequency band.

Keywords：环形天线；宽带天线；极化分集；方向图分集

HTML PDF Collect

利用对称结构和结合差分进化的文化算法检测阵列中的故障传感器 Article

Shafqat Ullah KHAN,Ijaz Mansoor QURESHI,Fawad ZAMAN,Wasim KHAN

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 2, Pages 235-245 doi: 10.1631/FITEE.1500315

Abstract: 本文解决了从N个传感器组成的线性阵列中检测完全或部分缺陷传感器的问题。本文首先提出了一种线性阵列的对称结构，其次，基于结合差分进化的文化算法，建立了一种混合技术。

Keywords：文化算法；差分进化；线性对称传感器阵列

HTML PDF Collect

Omnidirectional Antenna Diversity System for High-Speed Onboard Communication Article

Yongjian Zhang, Yue Li, Weiquan Zhang, Zhijun Zhang, Zhenghe Feng

Engineering 2022, Volume 11, Issue 4, Pages 72-79 doi: 10.1016/j.eng.2020.10.014

Abstract:

In this article, an omnidirectional dual-polarized antenna with synergetic electromagnetic and aerodynamic properties is propounded for high-speed diversity systems. The propounded antenna comprises a probe-fed cavity for horizontally polarized radiation and a microstrip-fed slot for vertical polarization. Double-layer metasurfaces are properly designed as artificial magnetic conductor boundaries with direct metal-mountable onboard installation and compact sizes. An attached wedge-shaped block is utilized for windage reduction in hydrodynamics. The propounded antenna is fabricated for design verification, and the experimental results agree well with the simulated ones. For vertical polarization, the operating bandwidth is in the range of 2.37–2.55 GHz, and the realized gain variation in the azimuthal radiation pattern is 3.67 decibels (dB). While an impedance bandwidth in the range of 2.45–2.47 GHz and a gain variation of 3.71 dB are also achieved for horizontal polarization. A port isolation more than 33 dB is obtained in a compact volume of 0.247λ₀ × 0.345λ₀ × 0.074λ₀, where λ₀ represents the wavelength in vacuum at the center frequency, wherein the wedge-shaped block is included. The propounded diversity antenna has electromagnetic and aerodynamic merits, and exhibits an excellent potential for high-speed onboard communication.

Keywords： Antenna diversity system Aerodynamics Electromagnetics Omnidirectional radiation High-speed onboard communication

HTML PDF Collect

A comprehensive error calibration method based on dual uniform circular array Research Article

Jia-jia Zhang, Hui Chen, Song Xiao, Meng-yu Ni,zjj2015wuhan@163.com

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 10, Pages 1415-1428 doi: 10.1631/FITEE.1800240

Abstract: Based on the , a novel method is proposed to estimate the direction-of-arrival (DOA) and jointly calibrate , , and . In this paper, only one auxiliary source is required to generate three time-disjoint sources with the help of the rotation platform. Subsequently, according to the principle that the signal subspace is orthogonal to the noise subspace, the cost function is constructed. The alternating iteration method is used to estimate the coefficients of the three kinds of errors. During the process, the proposed algorithm makes full use of the structural characteristics of the array when estimating , while the signal phase matrix is used to eliminate the phase influence caused by the delay in signal arrival at the antenna array when estimating and . Compared with the algorithm using multidimensional nonlinear search, the proposed algorithm has lower computational complexity. Moreover, our algorithm does not require additional auxiliary sensors. Simulation results demonstrate that the proposed algorithm is effective and can precisely and comprehensively calibrate the errors in a .

Keywords：双圈均匀圆阵；幅相误差；位置误差；互耦误差；校正

HTML PDF Collect

Calculation and research on deepwater drilling riser flexural equation and natural frequency

Jiang Wei

Strategic Study of CAE 2011, Volume 13, Issue 5, Pages 66-73

Abstract:

Flexural equation was established in this paper, which was based on application of deepwater drilling riser and Ritz methods in elastoplastic mechanics. Axial tension, inclination angle, lateral gravity components and axial gravity components were considered. Therefore, simple calculation method for natural frequency of drilling riser was achieved. Free-hinged beam was taken as constraint condition of flexural equation combined with drilling string real conditions, which made research approach practical work more. Purpose of research was to provide reasonable design and selection for deepwater drilling riser, and provide a more efficient and applied method, which would show guiding significance for deepwater drilling operation.

Keywords： deepwater drilling drilling riser flexural equation natural frequency shape function

HTML PDF Collect

Vortex Tower Mall for Establishing Readily-made and Highly Effective Man-made Windbreak Forests to Convert Entire Deserts to Vast Green Lands

Yan James T

Strategic Study of CAE 2003, Volume 5, Issue 5, Pages 24-30

Abstract:

To transform and utilize desert,one has to withstand wind-and-rain and sand-and-stone storms, also,one has to set up in deserts numerous belts of windbreak forests. Then,one can engage in large-scale sandy-agriculture,improve the environment,and step-by-step transform entire deserts to vast green lands. Currently, all countries are unable to, or consider it impossible to accomplish these.

In this paper，it is suggested to use Vortex Tower Malls(VTM) and the vortex breakdown feature in fluid dynamics, together with interferences from stabilizing chambers, etc. , to convert incoming strong winds to random eddies and weak currents, and to establish “ readily-made and highly effective man-made windbreak forest”. Suitable weighs will be distributed in stablizing chambers to enable VTM to stand up against very strong wind storms. Within the weak-wind regions,one can engage in large scale sandy-agriculture, work with experts from various disciplines to transform and utilize deserts at suitable levels, to convert entire deserts to vast green lands,and to convert useless and trouble-causing deserts into valuable lands. Also, VTM can be used to protect work-bases for long-term and deep-in-depth exploration in deserts,so as to expedite discovery and evaluation of deeply buried and world-scale mineral resources.

Keywords： vortex tower mall man-made windbreak forests sandy-agriculture

HTML PDF Collect

The Optimization of the Monopulse Antenna Based on Genetic Algorithms

Wang Hongjian,Gao Benqing,Liu Ruixiang

Strategic Study of CAE 2002, Volume 4, Issue 5, Pages 84-87

Abstract:

The sum and difference patterns as well as the directivity of the monopulse antenna arrays are optimized based on genetic algorithms (GA). When only the sum pattern is optimized as usual, the difference pattern and gain can not be guaranteed, so the track precision and effective distance of the antenna or missile will be impaired. However, using GA, the sum pattern, difference pattern and directivity can be optimized thoroughly for the antenna design.

Keywords： monopulse antenna array genetic algorithm pattern directivity

HTML PDF Collect

A Polarization Programmable Antenna Array Article

Dingzhao Chen, Yanhui Liu, Ming Li, Pan Guo, Zhuo Zeng, Jun Hu, Y. Jay Guo

Engineering 2022, Volume 16, Issue 9, Pages 100-114 doi: 10.1016/j.eng.2022.03.015

Abstract:

Reconfigurable antennas are becoming a major antenna technology for future wireless communications and sensing systems. It is known that, with a single linear polarization (LP) reconfigurable antenna element, a preferred polarization can be produced from a set of multiple polarization states, thus improving the quality of the communication link. This paper presents a new concept of a polarization programmable reconfigurable antenna array that consists of a number of polarization reconfigurable antenna elements with a finite number of possible polarization states. By employing a new optimization strategy and programming the polarization states of all the array elements, we demonstrate that it is possible to realize any desired LP in the vectorial array radiation pattern with accurate control of sidelobe and crosspolarization levels (XPLs), thereby achieving the desired polarization to perfectly match that of the required communications signal. Both numerical and experimental results are provided to prove the concept, and they agree well with each other.

Keywords：阵列天线极化可编程天线可重构天线

HTML PDF Collect

Wideband circular-polarized transmitarray for generating a high-purity vortex beam Correspondence

Liangjie QIU, Xiuping LI, Zihang QI, Wenyu ZHAO, Yuhan HUANG,xpli@bupt.edu.cn

Frontiers of Information Technology & Electronic Engineering 2023, Volume 24, Issue 6, Pages 927-934 doi: 10.1631/FITEE.2200539

Abstract: In this correspondence, a wideband circular-polarized (CP) transmitarray (TA) in the Ka-band is presented for generating a high-purity vortex beam. The proposed element is composed of two identical combinations separated by an air layer. The subwavelength structure and double-resonance characteristics ensure the stable phase shift of the element within the 1-dB transmission bandwidth of 28.4%. A square aperture TA fed by a horn antenna is fabricated and measured. Owing to the honeycomb arrangement of elements, the mode purity of l=−1 is >0.93 in a wide band from 28.5 to 38 GHz. The measured peak gain is 22.3 dBic, and the 3-dB axial ratio bandwidth is 27.6%. The performance of the proposed antenna demonstrates its potential for high-capacity wireless communication and high-quality radar imaging.

Keywords：轨道角动量；涡旋波束；透射阵；宽带；高纯度

HTML PDF Collect

Microwave－Optical Frequency Standards at NIM：Realizing of Definition of Metre and Second

Li Tianchun

Strategic Study of CAE 2007, Volume 9, Issue 6, Pages 27-31

Abstract:

The paper presents the realization, at NIM, of SI time unit second using the NIM4 cesium fountain clock, SI length unit meter using a femto-second (FS) optical frequency comb and calibration of wavelengths of stabilized lasers by this FS comb. The uncertainty of NIM4 fountain clock was evaluated as 5 × 10 ^{- 15}. The frequency uncertainty of the FS optical comb locked to a H-maser, which is steered by NIM4 clock, was estimated as 2. 2 × 10^{- 14}. The function, significance of Cs fountain clock, stabilized lasers, optical comb and relationship among them are discussed. Finally the progress of NIM5 fountain clock and the construction of a Sr atom optical clock started in 2006 at NIM are reported.

Keywords： metrology frequency standard stabilized laser Cs fountain clock FS optical comb

HTML PDF Collect

Modern Advances in Neutrino Researches

Huang Zhixun

Strategic Study of CAE 2002, Volume 4, Issue 10, Pages 90-93

Abstract:

Work on neutrino's mass has been going on in Japan and several other countries since the early work of V. Lubimov in USSR inl980 and that of a work with W. Kundig at Zurich University inl986. At the present time, there are several laboratories concerned with the research aspects of such particles. It among the advances of all sorts of neutrinos, two main cruxes should be considered for this subject. One is that the similarity between the photon and the neutrino, the other is that the very interesting superluminal theory for neutrinos.

Keywords： neutrino faster than light (superluminal) tachyon photon

HTML PDF Collect

Research on Prony’s method modeling in multi-target detection of stepped-frequency radar

Hu Tiling,Li Xingguo

Strategic Study of CAE 2008, Volume 10, Issue 10, Pages 67-71

Abstract:

Stepped-frequency signal is a broad band signal which enhances range resolution of radar at the cost of increasing bandwidth. Baseband signal that is received in stepped-frequency radar can be thought of as the linear combination of exponential function which contains target information, while Prony algorithm is a mathematical mode which uses a linear combination of exponential function to describe equal space between sampling data. Extended Prony algorithm is applied to stepped-frequency radar, which can obtain more exact target information and overcome the shortcomings of using IDFT to synthesize high resolution range profiles. Corresponding modeling analysis and experiment simulation explain the advantages of Prony's method.

Keywords： high resolution radar stepped-frequency signal extended Prony’s method multi-scattering center

HTML PDF Collect

Trend Analysis of Precipitation of Arid Areas In China

Gao Qingxian,Xu Ying,Ren Zhenhai

Strategic Study of CAE 2002, Volume 4, Issue 6, Pages 36-43

Abstract:

In this paper, the historical precipitation data has been analyzed, the temporal spatial distribution of atmospheric precipitation of north and west of China have been studied in detail. Choosing 5 global climate change models recommended by IPCC, the atmospheric precipitation of China in 2030 has been analyzed under different scenario. Finally, the future trend of atmospheric precipitation in north and west of China is revealed and the preliminary judgment of the probability of mitigating the drought in north of China has been given.

Keywords： atmospheric precipitation climate change climate model water resources