MoM-based topology optimization method for planar metallic antenna design

The metallic antenna design problem can be treated as a problem to find the optimal distribution of conductive material in a certain domain. Although this problem is well suited for topology optimization method, the volumetric distribution of conductive material based on 3D finite element method (FEM) has been known to cause numerical bottlenecks such as the skin depth issue, meshed 'air regions' and other numerical problems. In this paper a topology optimization method based on the method of moments (MoM) for configuration design of planar metallic antenna was proposed. The candidate structure of the planar metallic antenna was approximately considered as a resistance sheet with position-dependent impedance. In this way, the electromagnetic property of the antenna can be analyzed easily by using the MoM to solve the radiation problem of the resistance sheet in a finite domain. The topology of the antenna was depicted with the distribution of the impedance related to the design parameters or relative densities. The conductive material (metal) was assumed to have zero impedance, whereas the non-conductive material was simulated as a material with a finite but large enough impedance. The interpolation function of the impedance between conductive material and non-conductive material was taken as a tangential function. The design of planar metallic antenna was optimized for maximizing the efficiency at the target frequency. The results illustrated the effectiveness of the method.

A novel parameterization method for the topology optimization of metallic antenna design

In this paper, based on a tangential interpolation function and an adaptively increasing penalty-factor strategy(TIPS), a novel parameterization method with a self-penalization scheme aimed for the topology optimization of metallic antenna design is proposed. The topology description is based on the material distribution approach.The proposed tangential interpolation function aims to associate the material resistance with design variables, in which the material resistance is expressed in the arctangent scale and the arctangent resistance is interpolated with the design variables using the rational approximation of material properties. During the optimization process, a strategy with an adaptively increasing penalty factor is used to eliminate the remaining gray scale elements, as illustrated in examples,in the topology optimization based on the proposed tangential interpolation function. Design results of typical examples express the effectiveness of the proposed TIPS parameterization.

Study of High Power ICRF Antenna Design in LHD

In large helical device （LHD）, antenna loadings are different for minority ion cyclotron heating （MICH with 38.47 MHz） and mode-converted ion Bernstein wave heating （MC-IBW with 28.4 MHz）, and it is necessary to improve antenna loading with low heating efficiency to avoid arching on transmission line. To design a new ion cyclotron range of frequencies （ICRF） antenna in LHD, calculation for a simple antenna model is conducted using three-dimensional electrical magnetic code （high frequency structure simulator, HFSS） for an water loading as an imaginary plasma with low heating efficiency. At resonant frequencies, antenna loading is sensitive to strap width, and resonant frequencies are strongly related to strap height. There is no differences of RF current profile on the strap surface between resonant frequency and non-resonant frequency. The strap should be perpendicularly placed against the magnetic field line, since Faraday-shield angle will lead to a decrease in the effective antenna height.

Generalized Odd-Even Mode Theory and Mode Synthesis Antenna Design Approach

In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed.In this context,general-ized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna.As is mathematically deduced and demonstrated,the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems.Thus,an elegant,closed-form formula is derived to ap-proximately calculate the“unbalance degree”of a straight dipole off-center fed by a symmetric twin-wire line.Design approaches for the simplest,linear,1-D multimode resonant antennas are introduced.Moreover,the“falling tone excitation”law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas(MPAs)and 2-D sectorial electric dipole antennas.Design examples with distinctive radiation performance are presented and discussed.Finally,possible development trends of multimode resonant antennas are prospected.

Reference Design of ICRF Antenna for EAST

An antenna array suitable for plasma heating and current drive has been designed for the ion cyclotron resonance frequency range （ICRF） heating on the EAST superconducting tokamak. The ICRF heating is planned to operate in a frequency range of 30 MHz to 80 MHz and hence the antenna geometry is optimized for 55 MHz. The design is based on the conventional strap antenna element. The coupling properties of the antenna are calculated with a slab model of the plasma for the antenna simulation. The coupling code is extended for the analysis of the toroidal antenna array separated by septa.

Off-axis two-mirror laser communication antenna designed using differential equations

In satellite laser communication technology, which is built between planets and between a planet and the Earth, the optical antenna is the key point. Thus, research on optical system design is important. The off-axis reflective system has no obscuration and hence possesses a high efficiency for energy transfer. This study proposes a novel method for designing a free-form off-axis reflective imaging system. This study also introduces differential equations that depend on Fermat＇s principle and sine condition. Finally, a free-form off-axis two-mirror optical system was designed by using the differential equation method. This system includes one intermediate image plane, in which the field of view （FOV） is -5° to -4° in the y-axis and -1° to 0° in the x-axis. The modulation transfer function was greater than 0.7 at 50 lp/mm, and the efficiency of energy transmission was high. The free-form off-axis two-mirror optical system involves a wide range of application prospects in the optical antenna used in the satellite laser communication systems. Moreover, the design method that used differ- ential equations was proven simple and effective.

A look at field manipulation and antenna design using 3D transformation electromagnetics and 2D surface electromagnetics

While many techniques have been developed for the design of different types of antennas,such as wire antenna,patch antenna,lenses,and reflectors,these cannot be said general-purpose strategies for the synthesis and design of antennas to achieve the performance characteristics specified by users.Recently,there has been an increasing need for the development of antenna design techniques because of the advent of 5 G and a variety of space,defense,biological,and similar applications,for which a robust and general-purpose design tool is not to be developed.The main objective of this study is to take a look at antenna design from the field manipulation point of view,which has the potential to partially fulfill this need.We review the existing field manipulation techniques,including field transformation methods based on Maxwell’s and wave equations,point out some limitations of these techniques,and then present ways to improve the performance of these methods.Next,we introduce an alternative approach for field manipulation based on two-dimensional(2 D)metasurfaces,and present laws of the generalized reflection and refraction that are based on 2 D surface electromagnetics.Then,we explore how to overcome the limitations of conventional reflection and refraction processes that are strictly bounded by the critical angle.Finally,we provide some application examples of field manipulation methods in the antenna design,with a view on developing a general-purpose strategy for antenna design for future communication.

Th-Shaped Tunable Multi-Band Antenna for Modern Wireless Applications

A compact,reconfigurable antenna supporting multiple wireless services with a minimum number of switches is found lacking in literature and the same became the focus and outcome of this work.It was achieved by designing a Th-Shaped frequency reconfigurable multi-band microstrip planar antenna,based on use of a single switch within the radiating structure of the antenna.Three frequency bands(i.e.,2007–2501 MHz,3660–3983MHz and 9341–1046 MHz)can be operated with the switch in the ON switch state.In the OFF state of the switch,the antenna operates within the 2577–3280MHz and 9379–1033MHz Bands.The proposed antenna shows an acceptable input impedance match with Voltage Standing Wave Ratio(VSWR)less than 1.2.The peak radiation efficiency of the antenna is 82%.A reasonable gain is obtained from 1.22 to 3.31 dB within the operating bands is achieved.The proposed antenna supports UniversalMobile Telecommunication System(UMTS)-1920 to 2170 MHz,Worldwide Interoperability and Microwave Access(WiMAX)/Wireless Broadband/(Long Term Evolution)LTE2500–2500 to 2690 MHz,Fifth Generation(5G)-2500/3500 MHz,Wireless Fidelity(Wi-Fi)/Bluetooth-2400 to 2480 MHz,and Satellite communication applications in X-Band-8000 to 12000 MHz.The overall planar dimension of the proposed antenna is 40×20mm2.The antennawas designed,along with the parametric study,using Electromagnetic(EM)simulation tool.The antenna prototype is fabricated for experimental validation with the simulated results.The proposed antenna is low profile,tunable,lightweight,cheap to fabricate and highly efficient and hence is deemed suitable for use in modern wireless communication electronic devices.

A Novel Beam Design Method for mm Wave Multi-Antenna Arrays with Mutual Coupling Reduction

To overcome the mutual coupling (MC) of multiple antennas in millimeter wave (mmWave) communication systems, a novel beam design method with low complexity is proposed in this paper. Firstly, an equivalent channel model incorporating the effect of MC is analyzed and established, and then an optimal precoding / combiner vector for beamforming is derived. On this basis, by using greedy geometric (GG) algorithm, a novel hybrid beam design method is proposed. Finally, the performance of proposed method is analyzed and compared with other traditional ones. The simulation results show that the proposed method has better suppression of the MC effect as well as lower complexity.

Overview of Co.Design Approach to RF Filter and Antenna

The filter and antenna are two key components of the radio frequency(RF)front-end.When the antenna is directly connected with the filter,additional mismatch losses will be caused.Therefore,the antenna and filter are integrated into a single device to provide both filtering and radiating functions.In this way,many advantages,like low cost,light weight,small size and lower insertion loss can be obtained.In this paper,the co-design approaches of RF filter-antenna are reviewed.Based on the open literatures,the integrated approaches of filtering antenna can be classified into five main categories:1)Co-design by optimizing the interfacing impedance,2)co-design according to the synthesis approach of filter,3)co-design by embedding novel resonators within the feeding structures,4)co-design by employing auxiliary physical structures,and 5)other methods.The RF filter-antenna system can improve the integration degree of RF frontend,reduce its size and cost,and optimize its performance.

大型精密测量相控阵雷达天线座力学仿真应用研究

超大规模雷达天线座结构系统复杂,造价高、研制周期紧张,如何保证天线座结构设计一次成功,满足雷达结构技术要求是天线座研制的难题。文中结合工程研制,从天线座结构系统力学设计,计算模型建模原则、建模方法、轴承等关键部位连接处理、仿真模型简化与等效,有无斜梁结构方案仿真结果比较与选取,以及轨道平面度、辅助支撑力确定到最终结构优化进行了阐述,对大型雷达天线座结构设计具有一定的指导意义。

Design of an 868 MHz Printed S-Shape Monopole Antenna

The purpose of this work is to design and analyze an s-shaped printed circuit board (PCB) monopole antenna. The antenna was analyzed to operate at a resonance frequency band of 868 MHz;acceptable in 915 MHz as well. The s-shape is selected due to the need of reducing the overall size of the normal monopole antenna. The printed antenna was designed with an approximate overall size of 39 × 56 mm2 of which the antenna’s upper side is 26 × 39 mm2 while its reference ground board was sized at 39 × 30 mm2. The antenna is fed by a strip line of 3 × 1.5 mm2, in series with a 4.4 pF capacitance and shunt with an 8.7 nH inductance for purpose of antenna’s impedance matching with the input. A couple of existing publications showed that PCB antenna is not a new technology;however not an old technology for telecommunication industry. The raised problem by this work was duly solved with HFSS as a tool;excellent results are presented. After duly matching the antenna’s impedance with 50 Ω microstrip feed-line, solutions for overall performance were analyzed and demonstrated optimal: radiation patterns were proven omnidirectional, antenna gain optimized. The present antenna prototype’s overall dimensions can be readjusted according to any industrial and manufacturing requests.

“电波与天线”课程思政探索与实践

深入推进课程思政教学的研究和实践,是高校立德树人的重要任务之一。“电波与天线”是电子信息工程技术专业的一门专业课,这门课在课程思政教学改革的探索与实践中,主要针对思政元素的挖掘、课程思政的具体实施、课后思政效果的评价等方面进行了研究,并通过充实原有教材、优化教学大纲、创新教学方法、改进评价体系、健全反馈机制等手段,进行教学实践。实践表明,采用课程思政教学改革的班级在教学效果上优于传统的班级。

一种低轨星载数据传输天线的设计

针对卫星星座互联网的建设需求,设计了一种低轨星载数据传输天线。低轨星载数据传输天线由反射器、座架机构、驱动控制系统组成,分别进行了介绍。反射器采用正馈环焦形式。座架机构为X-Y构型,具备过顶跟踪通信能力。驱动控制系统采用冷备份设计,提高系统可靠性。低轨星载数据传输天线性能指标满足要求,工作稳定可靠。

一种分段的超短波对数周期天线设计与实验

超短波的传播方式主要为视距传播,这种传播方式需要天线具有强方向性且有较高的增益。而对数周期天线是一种超宽带、中等增益的天线,非常适用于超短波通信。然而在超短波频段下,常规对数周期天线的长度较长,小型化程度不高。为了实现超短波对数周期天线的小型化,提出一种分段的超短波对数周期天线的设计方案。根据应用需求,在满足天线增益的情况下,采用分段设计缩减天线长度,同时调整集合线之间的夹角,以实现天线的阻抗匹配。经过仿真设计,天线在30~70 MHz频段内典型增益大于8 dBi,天线的长度缩减至7 m。采用基于无人机飞行平台的外场测试系统对天线进行实验测试,测试结果表明,天线在工作频率范围内驻波比小于1.5,测试与仿真的辐射特性基本一致。该天线具有带宽宽、增益高、结构简单等特点,可以满足实际场景中超短波天线的需求。

基于层间耦合的宽带毫米波超表面天线

通信技术快速发展,对高速、大容量通信需求迫切。然而,传统频谱资源受限,难以满足需求,毫米波天线备受瞩目。本研究旨在改善传统微带贴片天线的带宽和增益问题。通过加载超表面结构和加强层间耦合的方法,设计了24~50 GHz宽带毫米波超表面天线。该天线采用层压方式将超表面加载在介质层中,通过仿真分析了超表面参数对天线带宽的影响,从而确定最佳天线结构尺寸,并进行了天线的制作和性能测试。仿真和实测结果表明,该天线能够实现24~50 GHz的宽带,相比传统贴片天线,其带宽增加了52.23%,并具有良好的辐射特性和增益性能。该宽带毫米波超表面天线在宽频段通信、5G通信等领域具备广阔的应用前景。

具备全空域自动跟踪能力的天线设计与分析

设计了一种具备全空域自动跟踪能力的9 m口径天线,具备Ka频段全空域自动跟踪能力。介绍了这一天线的总体结构、机械结构和天馈子系统、控制子系统,对这一天线进行结构力学分析,得到重力作用下的刚度、风载作用下的刚度,以及强度。这一天线的最大结构应力小于材料屈服应力,满足强度要求。

绕月SAR天线热控设计

合成孔径雷达(SAR)天线是遥感卫星的重要载荷之一,面对月球轨道舱外天线复杂的外热流环境,结合轨道特点,对天线开展了详细的外热流分析,解析了月球环境的热设计难点,进行了针对性的热控设计,解决了极地轨道下天线在一个很大的外热流和极小的外热流间不断循环的问题。采用TMG软件对天线进行了热仿真分析,并利用热模拟件进行了热平衡试验。分析和试验结果表明,天线各单机温度满足指标要求。本文适用于平板SAR天线,对有源SAR天线的热控设计具有一定的借鉴意义。

结构优化在空间可展开天线中的应用及展望

空间可展开天线是航天领域发展的重要方向,具有重大战略意义和重要经济社会价值。首先,对结构优化技术、面向增材制造的拓扑优化与点阵填充等先进轻量化设计技术的应用进行综述;然后,根据典型使用环境和设计要求,着重介绍近年来结构优化技术在空间可展开天线零部件结构优化和馈源阵支撑结构概念设计中的典型应用案例;最后,考虑未来空间超大口径及高精度可展开天线的设计需求,对先进轻量化设计技术的应用前景进行展望。结构优化技术与设计经验相结合,正在推动设计理念的创新,将成为先进航天器设计的核心工具和必备的标准流程。

“天线与电波传播”课程中案例设计式教学的探索

“天线与电波传播”是电子信息类本科专业核心课程,是“电磁场理论”课程的深化与应用拓展。课程涉及诸多典型的天线,包括八木天线、平面螺旋天线、喇叭天线、微带天线等,天线结构较复杂,理论分析难度较大,大多需要近似分析。为了提高“天线与电波传播”课程的教学效果,针对典型天线设计较成熟的现状,在理论课程教学中采用案例设计式的教学方法,通过案例设计,让学生带着目标任务去学习,提升对“天线与电波传播”课程学习的兴趣和主动性。以矩形喇叭天线设计为案例,提出具体的矩形喇叭天线设计需求,学生运用所学的课程知识,通过运用电磁仿真软件进行设计,完成设计目标,增强获得感,并将理论的近似计算结果与仿真结果进行对比分析,深化学生理论与实际的联系。通过上述案例设计式教学,让学生由“接收天线”转变为“发射天线”,强化学生对课程知识的理解,增强学生的创新思维能力和综合分析能力。