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Effect of Surface Roughness in Micro-nano Scale on Slotted Waveguide Arrays in Ku-band

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 595-603页

作者： Na LI Peng LI Liwei SONG key lab.ratory of electronic equipment structure design of ministry of education xidian universityXi'an 710071China

Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.

关键词： Slotted waveguide arrays - Roughness model Micro/nano-scale Amplitude and phase errors Radiationcharacteristics

Coupling Modeling for Functional Surface of electronic equipment

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 497-499页

作者： Baoyan DUAN Congsi WANG Wei WANG key lab.ratory of electronic equipment structure design of ministry of education xidian universityXi'an 710071China

High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the... 详细信息

关键词： TT Coupling Modeling for Functional Surface of electronic equipment

Special Issue on Electromechanical Coupling Design for electronic equipment

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 495-496页

作者： Bao Yan DUAN Jian Rong TAN key lab.ratory of electronic equipment structure Design of ministry of education Xidian University State key lab.of CAD&CG Zhejiang University

With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,

关键词： In Special Issue on Electromechanical Coupling Design for electronic equipment Design

B-spline surface fitting and simplified GO/PO analysis of subreflector correction for large Cassegrain antenna distortion compensation

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Research in Astronomy and Astrophysics 2018年第7期18卷 53-62页

作者： You Ban Cong-Si Wang Shu-Fei Feng Wei Wang Bao-Yan Duan key lab.ratory of electronic equipment structure Design Ministry of Education School of Electromechanical Engineering Xidian University

The main surface of a large Cassegrain antenna consists of a large number of panels. There are inevitably random and systematic errors which will degrade the antenna pattern and limit its applicability when working at high frequencies. Correcting the subreflector surface is difficult to describe by a global expansion effectively with a small amount of data. This paper presents a simple and clear way for correcting the subreflector surface of a large Cassegrain antenna for achieving such compensation. The advantage of the method is that the geometrical optics （GO） analysis is extremely simplified by the concept of equivalent prime-focus paraboloid, and corrected deformations of the subreflector surface are determined by simple formulas which represent the relationship between distortions of the subreflector surface and phase of the main surface current. The final shape of the subreflector surface is represented by a B-spline surface. To obtain a satisfactory antenna pattern with the simplest subreflector surface, the optimal number of B-spline patches are searched by particle swarm optimization （PSO）. The shaping process is verified by compensating a 22-m Cassegrain antenna whose main reflector has 96 panels. The results are satisfactory and demonstrate the simplicity and effectiveness of the approach.

关键词： telescopes reflector antennas subreflector shaping compensation

A Reverse-Design Strategy for the Track Error of the Qi Tai Telescope Based on Pointing Accuracy

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Engineering 2022年第6期8卷 209-216页

作者： Na Li Baoyan Duan Xiangyang Li Bin Zheng Jiang Wu key lab.ratory of electronic equipment structure Design Ministry of EducationXidian UniversityXi’an 710061China

The Qi Tai Telescope(QTT),which has a 110 m aperture,is planned to be the largest scale steerable tele-scope in the ***,the telescope’s repeated pointing accuracy error should be less than 2.5 arc seconds(arcsec);thus,the telescope structure must satisfy ultra-high precision *** this pur-suit,the present research envisages a reverse-design method for the track surface to reduce the difficulty of the telescope’s design and ***,the distribution characteristics of the test data for the track error were verified using the skewness coefficient and kurtosis coefficient *** to the distribution characteristics,the azimuth track error was simulated by a two-scale *** error of the long period and short amplitude was characterized as large-scale and described by a trigonometric function,while the short period and high amplitude error was characterized as small-scale and simulated by a fractal *** on the two-scale model,effect of the error on the pointing accuracy was ***,the relationship between the root mean square(RMS)of the track error and the RMS of the pointing accuracy error of the telescope was ***,the allowable RMS value of the track error was derived from the allowable pointing accuracy *** validate the effectiveness of the new design method,two typical radio telescopes(the Green Bank Telescope(GBT)and the Large Millimeter Telescope(LMT))were selected as experimental *** comparison,the theoretical calculated values of the pointing accuracy of the telescope were consistent with the measured values,with a maximum error of less than 10%.

关键词： Reverse design Track error Large radio telescope Two-scale model Pointing accuracy

Analysis of electrical performances of planar active phased array antennas with distorted array plane

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Journal of Systems Engineering and electronics 2009年第4期20卷 726-731页

作者： Wang Congsi Bao Hong Zhang Fushun Feng Xingang key lab. of electronic equipment structure of ministry of education Xidian Univ. Xi'an 710071 P. R. China National key lab. of Antenna and Microwave Technology Xidian Univ. Xi'an 710071 P. R. China

The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and bowl-shape distortion, the model is established of the relationship between the electromagnetic performance and the position error of the radiated elements. The method is presented of analyzing the far-field pattern of the distorted rectangular active phased array antenna. The analysis results of a planar phased array antenna with different distortions grades prove the validity of the model. Therefore, by the method, the antenna designers may set the reasonable requirement on the structural tolerance in manufacturing antenna.

关键词： active phased array antenna distortion error radiated element structural tolerance

The Establishment and Analysis of the Structural-Electromagnetic Coupling Model of the Electrostatically Controlled Deployable Membrane Antenna

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Chinese Journal of electronics 2024年第2期33卷 479-487页

作者： Shunji ZHANG Yongzhen GU Wang ZHONG Qinggang ZHANG Qingdao University of Science and Technology key lab.ratory of electronic equipment structure Design of ministry of education Xidian University

A new structural-electromagnetic coupling(SEC) analysis based on quadratic elements is proposed to solve the mismatch problem between structural elements and electromagnetic grids of the electrostatically controlled deployable membrane antenna(ECDMA). Firstly, the ECDMA reflector surface is meshed and redefined by a series of quadratic elements. Without grid transformation, the calculating formulas for the far-field pattern of ECDMA are derived by the physical-optics method. Then the structural deformation of ECDMA is analyzed and the far-field pattern calculating formulas including deformation errors are developed. Simulation and experiment results show that the quadratic elements are effective and efficient in SEC analysis of the ECDMA, moreover, the electromagnetic grid size demand and the grid discretization error are reduced greatly.

关键词： Couplings Electrodes Analytical models Deformation Electromagnetic fields Electromagnetics Optimization

Two-step Structural Design of Mesh Antennas for High Beam Pointing Accuracy

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 604-613页

作者： Shuxin ZHANG Jingli DU Wei WANG Xinghua ZHANG Yali ZONG key lab.ratory of electronic equipment structure Design of ministry of education Xidian University Qian Xuesen lab.ratory of Space Technology China Academy of Space Technology

A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir- cular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence the beam pointing accuracy. A two-step structural design procedure is proposed to overcome the beam squint phenomenon for high beam pointing accuracy design of circularly polarized offset cable mesh reflectors. A simple structural optimal design and an integrated structural electromagnetic optimization are combined to alleviate the beam squint effect of circular polarizations. It is imple- mented by cable pretension design and adjustment to shape the offset cable mesh surface. Besides, in order to increase the efficiency of integrated optimization, an update Broy- den-Fletcher-Goldfarb-Shanno （BFGS） Hessian matrix is employed in the optimization iteration with sequential quadratic programming. A circularly polarized offset cable mesh reflector is utilized to show the feasibility and effectiveness of the proposed procedure. A high beam pointing accuracy in order of 0.0001~ of electromagnetic performance is achieved.

关键词： Cable mesh reflector antennas Structuraldesign Beam squint Beam pointing accuracy

Optimal subreflector position determination of shaped dual-reflector antennas based on the parameters iteration approach

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Research in Astronomy and Astrophysics 2019年第4期19卷 151-160页

作者： Bin-Bin Xiang Cong-Si Wang Pei-Yuan Lian Na Wang You Ban key lab.ratory of electronic equipment structure Design of ministry of education School of Mechano-Electronic Engineering Xidian University Xinjiang Astronomical Observatory Chinese Academy of Sciences

A new method based on the parameters iteration technique has been developed to determine the optimal subreflector position for shaped Cassegrain antennas, that are distorted by gravity, to improve their electromagnetic(EM) performance. Both the features of shaped surface and the relationship between optical path difference(OPD) and far field beam pattern are employed. By describing the shaped dualreflector surface as a standard discrete parabola set, we can utilize the optical features of the standard Cassegrain system in the classical OPD relationship. Then, the actual far field beam pattern is expressed as the synthesis of ideal beam and error beam by decomposing subreflector adjustment parameters using a mechanical-electromagnetic-field-coupling-model(MEFCM). Furthermore, a numerical method for determining optimal subreflector position is presented. The proposed method is based on the iteration technique of subreflector adjustment parameters, and the optimal far field pattern is used for the iteration. The numerical solution of optimal adjustment parameters can be obtained rapidly. Results for a 25 m shaped Cassegrain antenna demonstrate that the adjustment of the subreflector to the optimal position as determined by the proposed method can improve the EM performance effectively.

关键词： methods:analytical methods:numerical telescope techniques:radar astronomy