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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    

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Nanobubble Dynamics in Aqueous Surfactant Solutions Studied by Liquid-Phase Transmission Electron Microscopy Letter

Yuna Bae, Sungsu Kang a,b, Byung Hyo Kim, Kitaek Lim, Sungho Jeon, Sangdeok Shim, Won Chul Lee, Jungwon Park

Engineering 2021, Volume 7, Issue 5,   Pages 630-635 doi: 10.1016/j.eng.2021.02.006

Abstract:

Nanobubbles have attracted considerable attention in various industrial applications due to their exceptionally long lifetime and their potential as carriers at the nanoscale. The stability and physiochemical properties of nanobubbles are highly sensitive to the presence of surfactants that can lower their surface tension or improve their electrostatic stabilization. Herein, we report real-time observations of the dynamic behaviors of nanobubbles in the presence of soluble surfactants. Using liquid-phase transmission electron microscopy (TEM) with multi-chamber graphene liquid cells, bulk nanobubbles and surface nanobubbles were observed in the same imaging condition. Our direct observations of nanobubbles indicate that stable gas transport frequently occurs without interfaces merging, while a narrow distance is maintained between the interfaces of interacting surfactant-laden nanobubbles. Our results also elucidate that the interface curvature of nanobubbles is an important factor that determines their interfacial stability.

Keywords： Nanobubbles     In situ TEM     Liquid-phase TEM     Surfactant    

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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    

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Correspondence: Monopulse transmitarray antenna fed by aperture-coupled microstrip structure Correspondence

Na KOU, Shixing YU, Zhao DING, Zhengping ZHANG,nkou@gzu.edu.cn,sxyu1@gzu.edu.cn,zding@gzu.edu.cn,zpzhang@gzu.edu.cn

Frontiers of Information Technology & Electronic Engineering 2022, Volume 23, Issue 3,   Pages 502-510 doi: 10.1631/FITEE.2000547

Abstract: Monopulse technique, also known as the simultaneous beam comparison method, is used mainly to measure the direction of arrival (DOA) (Sherman and Barton, 2011). Before the advent of monopulse technology, the method most widely used in radar direction finding was the lobe-switching technique (sequential lobing) (Lo, 1999). Compared with the sequential lobing method, the monopulse antenna can obtain information such as the pitch angle, azimuth angle, and distance of the target in a single pulse period (Vazquez-Roy et al., 2019). Due to the need for higher accuracy of angle measurement, the monopulse technique has been widely applied in SOTM missile guidance (Roy et al., 2019). When a monopulse system is working, multiple independent channels are adopted to receive signals reflected by targets at the same time. Then signals enter the comparator and finally the distance and angle information of targets can be obtained. There are three main types of monopulse antennas: lenses, reflectors, and arrays. A dielectric lens is generally a convex lens (Raman et al., 1998), which is difficult to manufacture due to its curved shape, high volume, and large mass. For common reflectors such as dish antennas, the feed and supporting structure are in front of the aperture, so a shielding effect will result in energy loss, sidelobe increase, and angle measurement error (Kou and Cheng, 2019). A more effective reflector is the Cassegrain antenna, which is more compact with dual reflectors (Zheng et al., 2016, 2017). However, the Cassegrain antenna has the problem of shielding effect caused by a secondary reflector and support rods. With growing demand for low cost and lightweight monopulse antennas in modern radar and telecommunications systems, array antennas are increasingly applied in monopulse antennas due to their characteristics of high gain and easy control of the beam direction. A typical example is the waveguide slot array, which has the advantages of low loss, low sidelobe level, and no aperture shielding problem (Vosoogh et al., 2018). The microstrip has attracted much attention in monopulse antennas because of its advantages of low profile, simple structure, and low cost (Yu et al., 2009; Kumar and Kumar, 2018). However, monopulse microstrip array antennas usually have a complex feed network, which often makes them large and expensive. In addition, substrate integrated waveguides (SIWs) (Cao et al., 2017; Zhu et al., 2018; Liu et al., 2019; Yang et al., 2019) and leaky wave antennas (LWAs) (Poveda-García et al., 2019) have been applied in monopulse antennas, with good results. Recently, reflectarrays have been proposed for use in monopulse antennas, and have shown good performance (Zhao et al., 2017, 2018). As an alternative to reflectarrays, transmitarrays not only have the advantages of reflectarrays, but also have no shielding effect from the feeds. Di Palma et al. (2016) proposed a 400-element reconfigurable transmitarray antenna to synthesize monopulse radiation patterns. However, the sum and difference patterns generated by the reconfigurable transmitarray antenna, which is controlled electronically by switches instead of by a SUM-DIFF comparator, are in time division.

Keywords： 孔径耦合；单脉冲天线；微带；透射阵列    

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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    

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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    

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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    

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The Dust Storm Phenomena in Ningxia and the Countermeasures

Gao Qingxia,Ren Zhenhai

Strategic Study of CAE 2002, Volume 4, Issue 2,   Pages 16-21

Abstract:

Based on the historical observation data from meteorological stations of Ningxia region, the spatial distribution and trend of dust storm phenomena (include dust storm, blowing sand and floating sand) are analyzed. Countermeasures for preventing and controlling sandstorm as well as desertification are put forward.

Keywords： dust storm     preventing and controlling dust storm and desertification     countermeasures and suggestion     blowing sand     floating sand    

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Extended Hemispherical Lens and Its Applications in Millimeter Wave Focal Imaging Systems

Sun Zhongliang,Dou Wenbin

Strategic Study of CAE 2000, Volume 2, Issue 3,   Pages 42-47

Abstract:

Recently millimeter wave imaging absorbs many attentions. Especially much research work has been done on the millimeter focal imaging because of its advantage of real time imaging. This paper analyzes extended hemispherical lens, which can be used in focal imaging. An integrated antenna array is placed at the back plane of the lens to receive the power focused by the lens. This structure can eliminate the effect of the surface wave exited in the thick dielectric substrates at millimeter wave wavelengths. Low loss and compact are its merit. Assuming an electromagnetic wave is incident on the lens surface, the field distribution in focal space of the lens is analyzed by using Stratton-Chu formula and ray tracing method. It will provide much information about the imaging performance of the lens. Experiments have been carried out for two types of incident waves, one is normally incident plane wave and another is Gaussian-beam. Good agreement has been found between experiments and calculation results. The lens antenna also can be used to eliminate the transition between paraboloidal antenna and integrated front-end in conventional integrated millimeter wave systems so that the system loss can be decreased and performance can be improved. Furthermore, the lens can be used to couple with a quasi-optical system. The results presented here will provide useful guidelines for the above mentioned applications.

Keywords： millimeter waves     antennas     imaging     extended hemispherical lens    

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Interphase precipitation in low carbon Ti-V microalloyed steels

Jia Tao,Wei Jiao,Feng Jie,Zhang Weina,Liu Zhenyu and Wang Guodong

Strategic Study of CAE 2014, Volume 16, Issue 1,   Pages 88-92

Abstract:

The present study focuses on the Ti-V microalloying system which draws less attention. By using the Formaster-FII dilatometer，the sample was held at austenite/ferrite dual- phase temperature region and the Ti-V complex interphase precipitates were obtained during the austenite to ferrite transformation. Optical Microscopy （OM） and transmission electron microscopy （TEM） were employed to analyze the microstructure，especially the morphology of the interphase precipitate and its crystallographic orientation relationship with ferrite matrix. Studies show that 650 ℃ is the nose temperature for static isothermal transformation. The interphase precipitates exhibit sheet-like distribution，including flat and curved sheets and adopt Baker-Nutting orientation relationships with the ferrite matrix.

Keywords： Ti-V microalloyed steel     interphase precipitation     isothermal phase transformation     TEM    

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Optimal design of a large dual-polarization microstrip reflectarray with China-coverage patterns for satellite communications Research Articles

Gang ZHAO, Yong-chang JIAO, Guan-tao CHEN

Frontiers of Information Technology & Electronic Engineering 2020, Volume 21, Issue 1,   Pages 159-173 doi: 10.1631/FITEE.1900496

Abstract: A large dual-polarization microstrip reflectarray with China-coverage patterns in two operating bands is designed. To sufficiently compensate for the spatial phase delay differences in two operating bands separately, a three-layer rectangular patch element is addressed, which is suitable for the large dual-polarization reflectarray. Due to the complexly shaped areas and high gain requirements, there are more than 25 000 elements in the reflectarray, making it difficult to design, due to more than 150 000 optimization variables. First, the discrete fast Fourier transform (DFFT) and the inverse DFFT are used to establish a one-to-one relationship between the aperture distribution and the far field, which lays a foundation for optimizing the shaped-beam reflectarray. The intersection approach, based on the alternating projection, is used to obtain the desired reflection phases of all the elements at some sample frequencies, and a new method for producing a suitable initial solution is proposed to avoid undesired local minima. To validate the design method, a dual-polarization shaped-beam reflectarray with 7569 elements is fabricated and measured. The measurement results are in reasonable agreement with the simulation ones. Then, for the large broadband reflectarray with the minimum differential spatial phase delays in the operating band, an approach for determining the optimal position of the feed is discussed. To simultaneously find optimal dimensions of each element in two orthogonal directions, we establish a new optimization model, which is solved by the regular polyhedron method. Finally, a dual-band dual-polarization microstrip reflectarray with 25 305 elements is designed to cover the continent of China. Simulation results show that patterns of the reflectarray meet the China-coverage requirements in two operating bands, and that the proposed optimization method for designing large reflectarrays with complexly shaped patterns is reliable and efficient.

Keywords： Reflectarray     Dual-polarization     Shaped beam     Phase-only synthesis    

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The Regional Characteristics of the Atmospheric Environment and the Impact of Dust-storm in Beijing

Ren Zhenhai,Gao Qingxian,Su Fuqing,Wang Yaoting,Zhang Zhigang,Yang Xinxing

Strategic Study of CAE 2003, Volume 5, Issue 2,   Pages 49-56

Abstract:

The regional characteristics of the atmospheric environment and the impact in Beijing were discussed in details. Applying point set for the network, the transport passageways of the atmosphere were determined, and the concept of converging zone was put forward, and the characteristics of atmospheric pollution were analyzed. Applying the laser techniques, the vertical distribution of the aerosol was detected. It was shown that the environmental quality of the atmosphere in Beijing was relative to the pollution sources in the neighborhood around Beijing area. And it was confirmed that only by the simultaneous treatment of the pollution source in both Beijing and its neighborhood areas, can the environmental quality of the atmosphere in Beijing be improved.

By both the satellite detection techniques and the analysis of the wind stream fields of the atmosphere, the phenomena of dust-storm in China were researched, and the inner source and outersource of the dust-storm in China were determined. The especially strong dust-storm on March 22, 2002, was taken as an example, by which the distribution of the original sources of the dust-storm was resolved, and the lots of the bare lands in Spring in the north of the Yangzei River were involved. The initial process of the dust-storm appeared as a group of point sources, which were then combined into a sand-dust band. Finally, the dust-storm pollution of the large areas would appeare. The modern theory and concept for the environment in China were described chiefly.

Keywords： dust-storm     transport passageway     environment pollution     China    

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Low-cost high-order-mode cavity backed slot array antenna using empty substrate integrated waveguide for the 5G n260 band

Zihang Qi, Xiuping Li, Hua Zhu,qizihang@bupt.edu.cn,xpli@bupt.edu.cn,judy-cool@163.com

Frontiers of Information Technology & Electronic Engineering 2021, Volume 22, Issue 4,   Pages 609-614 doi: 10.1631/FITEE.2000503

Abstract: A low-cost slot array antenna is proposed for fifth-generation wireless communication (5G) n260 band applications. The antenna is based on the low-cost printed circuit board (PCB) material FR-4. Empty substrate-integrated waveguide is used to avoid high dielectric loss. High-order-mode cavities are introduced to reduce the complexity of the feeding network. The proposed antenna shows a maximum realized gain of 27 dBi with a radiation efficiency of 72.4%. The measurement and simulation results achieve good agreement. The proposed antenna can be a good candidate for low-cost millimeter-wave (mmWave) wireless communication systems.
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Three-dimensional localization of near-field and strictly noncircular sources using steering vector decomposition Research Article

Zheng LI, Jinqing SHEN, Xiaofei ZHANG,lizhengjsnj@163.com,zhangxiaofei@nuaa.edu.cn

Frontiers of Information Technology & Electronic Engineering 2022, Volume 23, Issue 4,   Pages 644-652 doi: 10.1631/FITEE.2100034

Abstract: The three-dimensional problem for in with a is rarely studied. In this paper, we propose an algorithm with improved estimation performance. We decompose the multiple parameters of the steering vector in a specific order so that it can be converted into the products of several matrices, and each of the matrices includes only one parameter. On this basis, each parameter to be resolved can be estimated by performing a one-dimensional spatial spectral search. Although the computational complexity of the proposed algorithm is several times that of our previous algorithm, the estimation performance, including its error and resolution, with respect to the direction of arrival, is improved, and the range estimation performance can be maintained. The superiority of the proposed algorithm is verified by simulation results.

Keywords： Localization     Centro-symmetric cross array     Noncircular sources     Near-field     Steering vector decomposition    

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A scheduling method based on a hybrid genetic particle swarm algorithm for multifunction phased array radar Article

Hao-wei ZHANG, Jun-wei XIE, Wen-long LU, Chuan SHENG, Bin-feng ZONG

Frontiers of Information Technology & Electronic Engineering 2017, Volume 18, Issue 11,   Pages 1806-1816 doi: 10.1631/FITEE.1601358

Abstract: A hybrid optimization approach combining a particle swarm algorithm, a genetic algorithm, and a heuristic inter-leaving algorithm is proposed for scheduling tasks in the multifunction phased array radar. By optimizing parameters using chaos theory, designing the dynamic inertia weight for the particle swarm algorithm as well as introducing crossover operation and mutation operation of the genetic algorithm, both the efficiency and exploration ability of the hybrid algorithm are improved. Under the frame of the intelligence algorithm, the heuristic interleaving scheduling algorithm is presented to further use the time resource of the task waiting duration. A large-scale simulation demonstrates that the proposed algorithm is more robust and effi-cient than existing algorithms.

Keywords： Phased array radar     Scheduling     Particle swarm algorithm     Genetic algorithm     Pulse interleave    

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Title Author Date Type Operation

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

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

Journal Article

Nanobubble Dynamics in Aqueous Surfactant Solutions Studied by Liquid-Phase Transmission Electron Microscopy

Yuna Bae, Sungsu Kang a,b, Byung Hyo Kim, Kitaek Lim, Sungho Jeon, Sangdeok Shim, Won Chul Lee, Jungwon Park

Journal Article

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

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

Journal Article

Correspondence: Monopulse transmitarray antenna fed by aperture-coupled microstrip structure

Na KOU, Shixing YU, Zhao DING, Zhengping ZHANG,nkou@gzu.edu.cn,sxyu1@gzu.edu.cn,zding@gzu.edu.cn,zpzhang@gzu.edu.cn

Journal Article

A comprehensive error calibration method based on dual uniform circular array

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

Journal Article

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

Journal Article

Trend Analysis of Precipitation of Arid Areas In China

Gao Qingxian,Xu Ying,Ren Zhenhai

Journal Article

The Dust Storm Phenomena in Ningxia and the Countermeasures

Gao Qingxia,Ren Zhenhai

Journal Article

Extended Hemispherical Lens and Its Applications in Millimeter Wave Focal Imaging Systems

Sun Zhongliang,Dou Wenbin

Journal Article

Interphase precipitation in low carbon Ti-V microalloyed steels

Jia Tao,Wei Jiao,Feng Jie,Zhang Weina,Liu Zhenyu and Wang Guodong

Journal Article

Optimal design of a large dual-polarization microstrip reflectarray with China-coverage patterns for satellite communications

Gang ZHAO, Yong-chang JIAO, Guan-tao CHEN

Journal Article

The Regional Characteristics of the Atmospheric Environment and the Impact of Dust-storm in Beijing

Ren Zhenhai,Gao Qingxian,Su Fuqing,Wang Yaoting,Zhang Zhigang,Yang Xinxing

Journal Article

Low-cost high-order-mode cavity backed slot array antenna using empty substrate integrated waveguide for the 5G n260 band

Zihang Qi, Xiuping Li, Hua Zhu,qizihang@bupt.edu.cn,xpli@bupt.edu.cn,judy-cool@163.com

Journal Article

Three-dimensional localization of near-field and strictly noncircular sources using steering vector decomposition

Zheng LI, Jinqing SHEN, Xiaofei ZHANG,lizhengjsnj@163.com,zhangxiaofei@nuaa.edu.cn

Journal Article

A scheduling method based on a hybrid genetic particle swarm algorithm for multifunction phased array radar

Hao-wei ZHANG, Jun-wei XIE, Wen-long LU, Chuan SHENG, Bin-feng ZONG

Journal Article