An Optimal Antenna Assignment Strategy for Information Raining

This paper addresses the antenna assignment problem for distributed multiple-antenna architecture that enables wireless communication between onboard and ground in subway and railway. We propose a class of algorithms that match the assignment pattern to the large scale fading. Such algorithms are not constrained by short coherence time inherited in subway and railway. We will then derive an optimal antenna assignment strategy employing maximum ratio combining. Simulation results will be provided to demonstrate the advantages of the proposed strategy, which can also be applied to the recently proposed information raining system.     

微波定向天线对准实现方法

论述了微波通信中,根据通信双方站点的经纬度可计算得出通信距离、通信方位角和俯仰角,并查阅站点所在地理位置的磁偏角进行方位角的校正。根据通信距离、工作频率和天线增益等参数,计算信号理论接收电平,依据方位角和俯仰角去调整定向天线方位,当天线接收信号测试电平与理论值相当时则认为天线实现了对准。给出了通过全向天线或低增益天线作辅助实现定向天线对准的方法。     

An Optimal Design of Fractal Antenna with Modified Ground Structure for Wideband Applications

This paper premeditates an optimal design of fractal antenna with modified ground structure for wideband applications. The proposed antenna has been designed by taking numerous iterations started from 0th to 3rd. To attain the wideband characteristics, the partial ground plane has been introduced in the 3rd iteration, and the length of the ground plane has been varied to enhance the bandwidth. The maximum value of bandwidth has been adorned in the final iteration as 1.88 and 0.20 GHz. Further, this bandwidth has been improved and embellished as 2.48 GHz within the frequency range of 3–6 GHz by employing horizontal and vertical extensions in the partial ground plane. Antenna is simulated by using HFSS and performance parameters of antenna like return loss (S_11?≤???10 dB), gain and radiation efficiency are in the acceptable limits. The maximum value of gain is reported as 5.1 dB and radiation pattern is also omnidirectional. The proposed antenna is useful for the wireless applications as WiMAX (3.4–3.69 GHz) and WLAN (5.15–5.35 and 5.72–5.82 GHz) Simulated and experimental results are also juxtaposed and found in good agreement with each other.     

“微波技术与天线”课程EIP-CDIO融合教学方法

本文以＂微波技术与天线＂课程为例,展示了EIP-CDIO教育模式的理论与实践教学相结合教学改革新方法。我们以独特的授课方式和科学的培养方案为基础,强调理论研讨与团队实践的有机结合,并在培养过程中注重人文精神的熏陶,可使学生的责任感、观察力、创造力和工程能力得到加强。实践教学结果表明,本教学实践方法在理论知识掌握和创新能力培养上,教学效果优于传统教学模式。     

高功率微波武器与天线（一）

自1973年前苏联用相对论返波管产生10 ns 400 MW的脉冲输出到2003年美国高功率电磁脉冲炸弹首次用于伊拉克战争,高功率微波武器的发展已近半个世纪,微波武器的概念目前尚未被大众所知。首先简要综述了高功率微波系统的组成、基本概念,以及高功率微波的发展历史、世界各国研究现状和高功率微波的基本效应、威力、对抗高功率微波的措施、研究中的安全防护、研究高功率微波的仪器、仪表、设备、方法及手段;最后分析了目前的水平和困难、高功率微波能量传输的极限及高功率微波武器的安全问题。     

The Beamed Power Microwave Transmitting Antenna

The potential applications, resulting hazards, safety considerations, and alternate options for high-power microwave beam transmission functions are discussed. Existing and projected beamed power control techniques are presented, and the differences between existing and proposed high-power conventional antennas and phased arrays are described.     

动中通多子阵天线自适应PID滑模稳定控制

动中通在载体运动中进行卫星通信时,天线受到各类扰动的影响而不能准确对准卫星,降低了通信质量。为了解决此问题,设计了一种自适应滑模天线姿态稳定控制器。首先建立了动中通天线系统的动力学模型;基于此模型,采用PID滑模面设计了天线的滑模姿态控制器;通过对扰动的自适应估计,在扰动上界未知情况下获得了平滑的滑模控制输入;将PID方法引入控制器设计,提高了系统的动态响应速度。仿真结果表明,所设计控制器具有良好的动态响应特性和控制精度,且控制电压输出无抖振。     

超高性能微波天线馈源系统的设计

本文介绍了用于微波接力天线馈源中的C波段超高性能馈源系统的设计方法,利用高频结构仿真软件对其进行了优化设计。对一些重要的和不易调整的尺寸用加偏差的方法来确定加工精度。计算结果与实测结果吻合的较好,在4．4～5GHz的频段中,整个馈源系统的驻波优于1．05,交叉极化鉴别率优于-40dB。     

Multiuser Diversity for Antenna Optimal Combining in Interference-Limited Systems

This letter explores the benefit of exploiting multiuser diversity for improving the performance of antenna optimum combining in the interference-limited cellular system. The asymptotic achievable rate is derived to assess this improvement as well as to reveal the interaction of multiuser diversity and optimum combining. For the overloaded case where the number of antennas is insufficient to suppress all the impact of interferers, it is shown that multiuser diversity considerably improves the achievable rate. For the underloaded case where the number of interferers is smaller than that of antennas, multiuser diversity can also provide additional rate increments so that it is possible to use a fewer number of antennas for optimum combining without sacrificing the system achievable rate.     

Optimal Antenna Radiation Characteristics for Diversity and MIMO Systems

This paper proposes a method for determining the antenna element radiation characteristics that maximize diversity gain given a specific power angular spectrum of the propagation environment. The method numerically constructs the eigenfunctions of the covariance operator for the scenario subject to constraints on the radiated power and allowable level of supergain. The discussion also focuses on how the resulting radiation characteristics approximately optimize average capacity for multiple-input multiple-output communications. Computational results reveal that optimal antenna characteristics can provide significantly more diversity gain than that offered by the characteristics of a simple design. An example computation using genetic algorithm optimization demonstrates that a numerically optimized practical design can be designed whose performance is relatively close to that of the optimal array.      

微波天线差波束特性分析

从工程应用的角度出发,在理论上分析了影响两种基本类型微波天线差波束的零值深度、零点位置等指标的因素。给出的结论在不同产品的设计和生产中都得到了证实,起到了很好的指导作用。     

多频道微波分配系统天线设计

本文简要介绍了采用同轴馈电的圆柱缝隙阵来完成水平极化的MMDS天线设计和利用圆柱上的对称振子来设计垂直极化的MMDS天线的设计过程和设计方法.     

数字微波天线高度的计算机辅助设计

基于数字微波工程设计中天线高度设计的重要性,本文结合作图法的步骤和特点,利用计算机辅助设计,提出了一种改进的求解天线高度的方法。这种方法简单快速,准确可靠,能大大缩短工程设计周期,提高工作效率和设计质量。文章重点介绍了求解天线高度的改进模型、设计思路、编程步骤和结果验证,希望对从事微波工程设计人员提供参考和帮助。     

物联网微波能量传输系统天线的研究

本文研究的是面向物联网应用的无线能量传输系统,通过改进微带馈电缝隙接收天线的微波滤波器的设计,不仅解决了接收频带窄的难题,而且提高了对2.45GHz和5.8GHz两种频率微波能量的接收效率.     

宽带圆极化微波电视全向发射天线

本文介绍一种宽带圆极化微波电视全向发射天线，该天线具有频带宽，结构简单，体积小，重量轻，便于安装，成本低等特点，已应用在多个微波电视传输工程中。     

A Cat-Shaped Patch Antenna for Future Super Wideband Wireless Microwave Applications

Wireless Personal Communications - Compact super wideband (SWB) monopole antenna with a novel Cat-shaped patch is proposed and investigated for wireless applications in this article. The...     

面向微集成的金刚石NV色心与微波天线的一体化

针对金刚石氮空位(NV)色心量子传感器中微波天线体积大、无法与金刚石紧密接触造成天线与金刚石位置不固定、引起传感器灵敏度低的问题,设计了一种将微波天线集成到金刚石NV色心的一体化方法.采用导电性更强的金薄膜作为天线材料,通过高频结构模拟器(HFSS)仿真软件确定天线尺寸.利用微纳加工工艺和磁控溅射技术在金刚石NV色心表...     

Optimal Characteristics of an Arbitrary Receive Antenna

Several fundamental questions about the operation of receiving antennas are addressed, such as “Why does a receiving antenna scatter an incident field?” and “Under what conditions does a receive antenna capture all of the available incident power?” A new method is described by which the received power can be maximized for an arbitrary receiving antenna. The technique is first illustrated for two-dimensional infinite receiving arrays of electric and/or magnetic dipole elements, which result in simple plane waves for the scattered (re-radiated) fields. Optimal results (for maximum received power) are derived for several cases, and it is established that half the available incident power may be received by an array of electric (or magnetic) elements in free space, and that all available incident power may be received by an array that combines electric and magnetic elements, or one that incorporates a ground plane. Next, an arbitrary finite three-dimensional antenna enclosed by a mathematical spherical surface is treated using spherical vector wave functions. It is shown that half the available incident power can be received by such an antenna consisting of either TM or TE only elements, while all available incident power can be received when both TM and TE elements are used. It is also shown that the absorption efficiency for any optimal arbitrary antenna is 50%.      

微波通信线路中天线塔高的优化设计

本文利用余隙标准,考虑微波接力通信线路的不同反射系数,对线路中天线塔高进行优化设计;采用最优化计算方法中的直接搜索法,得出了符合余隙标准的最低塔高尺寸;通过对一些工程实例的计算模拟结果表明,该方法不胆能节省大量冗繁的手工计算,而且对降低线路成本具有很大的作用及意义。     

An Adjustable Sliding Termination for Rectangular Waveguide

A new adjustable sliding termination for rectangular waveguide has been developed. The termination is of simple design and can easily be adjusted to have reflection coefficients from zero to nearly unity in magnitude and any desired phase. In addition to the usual applications of adjustable sliding terminations for rectangular waveguide, it provides a suitable design for an adjustable transferor secondary standard of impedance for rectangular waveguide systems.