一种基于电调移相器的可重构天线

设计并实现了一种基于反射式移相器的极化可重构天线。该天线使用一对交叉摆放的领结型振子作为辐射单元,并在馈电网络中通过两路移相器调整双馈端口间的相位差实现线极化、左旋圆极化和右旋圆极化模式之间的切换。通过加载匹配枝节的方法扩展了反射式移相器的移相范围,提高了移相器的移相精度,降低了天线圆极化模式带内的轴比。所设计天线的中心频率为5.4 GHz,在线极化模式下10 dB 阻抗带宽为990 MHz,在圆极化模式下10 dB 阻抗带宽分别为760 MHz 和850 MHz,3 dB 轴比带宽分别为510 MHz和480 MHz。该天线在频带内具有稳定的波束方向图,其平均增益为5.3 dB,并且具有27 dB 的主极化-交叉极化隔离。最终的实测结果与仿真结果基本一致,表明该天线具有良好的性能。     

TD—LTE多频段协同优化探讨

中国移动已开展全国范围r8的TD-LTE网络新一期工程部署工作,室外宏基站和室内基站规模进一步扩大。从中国移动来看,GSM900、GSMl800、TD-SCDMA、TD-LTEF频段、TD-LTED频段的共存将导致“3模5频”组网方案的普遍存在,无论是F频段直接升级、F频段新建还是D频段新建都会大量涉及共站共天馈。而天线方向角和下倾角无法独立调整,因此也必然需要TD-LTE与TD-SCDMA的协同优化。     

数字馈相条件下相控阵天线波瓣指向精度分析

在分析数字馈相对相控阵天线波瓣指向精度的影响的基础上,通过数值模拟和分析,给出了数字馈相条件下天线波瓣最大指向误差与移相器位数之间的定量关系,并导出了移相器位数的一种选取标准。模拟计算表明,天线波瓣最大指向误差仅与阵元间距与工作波长比值以及移相器位数有关,应对这两个参数进行合理选取以提高天线波瓣的指向精度。     

一种新型多层PCB多频段电场测量传感天线

移动通信基站电磁辐射信号的监测是移动通信正常工作的重要保证,也是保障电磁环境安全的必要手段.文章针对监测设备核心部件——电场测量传感天线的需求,设计了一种新型的介质埋藏式多频段振子天线.利用多层印制电路板（printed circuit board,PCB）布板技术,将三个串馈微带印刷振子天线埋藏在介质基板中,可有效减小天线尺寸.通过仿真和优化实现电场测量传感天线的设计,并制作了天线实物,同时进行了参数测量,结果表明:天线工作的频段基本覆盖2G、3G、4G网络的工作频率范围,分别为0.850~0.950 GHz,1.670~2.740 GHz,方向图全向性好,大小为72.0 mm×48.0 mm×6.0 mm,可以达到测量移动通信基站电磁辐射的电场测量传感天线的专用性、多频段、灵敏度、各向同性和便携性要求.可以使用本文设计的电场测量传感天线来测量基站周围空间电场强度.     

移动通信基站天馈系统现场测试研究

传统衡量基站天线以及天线馈线性能的方法是按照相应产品标准,在实验室内进行分别测量。在实际的应用环境中,基站天线和馈线共同组成基站天馈系统。基站天馈系统的电气性能指标直接影响其所覆盖小区内语音以及数据业务质量。传统的基站天线、馈线的测量方法不能有效衡量基站天馈系统在实际应用环境中的性能。本文通过实地检测,对基站天馈系统电气性能进行了摸底,并对这种现场测试的可行性进行了探索。     

移相器对电调天线的影响分析

作为电调天线最核心的部件,移相器的选择将直接影响到天线整机的性能.目前,基站天线行业普遍使用的移相器主要有以下两种类型:介质移相器、带线耦合移相器.重点针对介质移相器和带线耦合移相器进行分析,研究探讨其对天线整机性能的影响,以及在设计和应用移相器的过程中需要关注的要点,为电调天线的设计和进一步发展提供参考.     

跨频共站升级LTE FDD网络天线下倾角优化策略分析

在800MHz频段现有CDMA网络共站升级2.1GHz频段LTE FDD网络。以密集市区站间距500m场景为例,首先分析2.1GHz频段天线下倾角对LTE FDD网络覆盖性能和容量性能的影响,给出相应的最优天线下倾角配置原则;然后通过与800MHz频段网络最优天线下倾角进行比较,给出跨频共站升级方案天线下倾角的优化策略。跨频共站升级LTE FDD网络方案天线下倾角优化策略的研究,可为4G网络的升级与部署提供可靠的参考数据。     

TD-SCDMA与TD-LTE协同优化研究

从中国移动来看,GSM900、GSM1800、TD-SCDMA、TD-LTE F频段、TD-LTE E频段、TD-LTE D频段的共存将导致“3模6频”组网方案的普遍存在,无论是E、F频段直接升级,还是D、E、F频段新建都会大量涉及共站共天馈。而天线方向角和下倾角无法独立调整,因此也必然需要TD-LTE与TD-SCDMA的协同优化。     

相控阵串馈开关内校正高副瓣的消除

简述了相控阵天线BIT行波串馈开关内校正方法,该校正方法在角θ-sin^-1（λ／λg）处引入一个高电平副瓣。分析认为,非待检单元间信号的窜扰及其在行波线网络中传输的线性相差是导致高副瓣出现的主要原因。在理论分析的基础上,提出了通过对各通道的移相器馈入和窜扰信号反向的线性相差以消除高电平副瓣的方法,结果表明所采用的方法效果良好。     

宽带双向微带天线设计

针对室内走廊或狭长街道小功率基站应用要求,采用微带结构设计了一款具有双向辐射特性的宽带线极化低剖面天线.天线辐射元为平行四边形结构,馈电点在其几何中心,通过在靠近馈点两侧开两个反对称L形槽,实现了宽带双向辐射特性.低剖面原型天线的相对带宽为5.8％,两端射方向增益约为4.3dBi,在工作频带内天线辐射场为有一定倾角的线极化.该天线结构可置于小功率基站内部,有助于减少系统体积.     

Receiving Phased Antenna Array Based on Injection-Locked Harmonic Self-Oscillating Mixers

A 4 times 1 element receiving phased antenna array is presented with phase-shifter elements based on injection-locked harmonic self-oscillating mixers. Each phase-shifter element provides the double functionality of variable phase-shifter and down-converter. The phase-shifts applied to the input signals coming from the different antenna patch elements can be selected by dc control signals in a continuous range of 450deg. The required dc control voltages are calculated for the different incident angles by means of harmonic balance simulations. The influences of phase-shift and conversion gain errors on the beam-steering frequency performance of the antenna are studied. Also illustrated is how the phase-shifter parameters can be optimized in order to minimize the frequency scanning. A 4 times 1 element receiving phased antenna array, with an input frequency band centered at 11.25 GHz and the output frequency band centered at 1.5 GHz, has been manufactured for the experimental validation of the simulated results. A beam scanning range from -23deg to 23deg has been experimentally obtained.     

一种应用于基站天线的新型球透镜

针对传统龙伯透镜结构复杂、制作工艺难度大、不易实现批量化生产等问题,提出了一种应用于基站天线的新型球透镜,采用同一种介质材料的一个介质基座和多个介质锥体,再将各介质锥体均匀分布连接于介质基座上,组成球透镜.仿真结果表明:采用所提出的球透镜的双极化基站天线,具有良好的辐射方向图和高增益性能.     

双环天线在3G基站中应用的研究与改进

双环天线在3G基站中的应用是一种新的探索与尝试。本文对双环天线在3G基站中应用的方向图特性、阻抗匹配以及宽频带性能等进行了仿真研究与分析。为了更好地抑制第一副瓣电平,提出了对双环天线进行改进的方案。通过仿真检验,改进后的双环天线能抑制第一副瓣电平约1.4dB。应用改进的双环天线设计了一种基站天线,测试的结果均达到了指标要求,证实了双环天线在3G中的适用性。     

一种适用于LTE和Sub-6 GHz频段的宽带双极化基站天线

提出了一种适用于LTE和Sub-6 GHz频段的紧凑型双极化基站天线辐射单元,辐射振子臂采用1.2 mm板厚的FR4基板双层印制工艺。利用在双极化辐射单元上方加载寄生单元的方式来扩展天线工作频带。实物测试结果显示天线工作频段可连续覆盖LTE(1.8 GHz^2.7 GHz)和5G的Sub-6 GHz频段(3.3 GHz^3.7 GHz),带内电压驻波比小于1.8,隔离度大于20 dB。天线最高增益为9.42 dBi,半功率波束宽度为60°±9°。测试和仿真结果吻合较好。可应用于4G和5G移动通信基站。     

移动通信基站天线的关键技术研究进展

基站天线作为移动通信系统中的重要部件,对通信质量起至关重要的作用,其关键技术被广泛研究。通过对基站天线的电调技术、极化技术、宽带技术、阵列天线多频技术和基站天线小型化技术等的研究发展历程介绍,分析了这些关键技术在工程上的实现方法与措施,总结了这5个关键技术今后的研究重点和发展方向。在基站天线下一步的发展中,需要将多个关键技术完美地结合在一起,阵列天线多频技术和基站天线小型化技术将成为今后的研究热点。     

Design and analysis of a microwave large-range variable phase-shifter based on an injection-locked harmonic self-oscillating mixer

In this letter, a new microwave variable phase-shifter based on an injection-locked harmonic self-oscillating mixer, is presented for its application in an active microstrip phased antenna array. The circuit provides the double functionality of variable phase-shifter and down-converter. Maximum conversion gain is obtained, through the optimization of a new multi-harmonic load at the input-port of the circuit. The ranges of synchronized operation are analyzed versus the circuit parameters and the corresponding phase-shifts are calculated. The stability of the synchronized solutions is analyzed using the envelope transient simulation method. An 11.25-1.5-GHz down-converter with a 3.25-GHz free-running frequency has been designed, providing a phase-shift variation at intermediate frequency up to 540/spl deg/, with a 4.5-dB conversion gain. A good agreement between the simulated and experimental results has been found.     

Two-dimensional beam-scanning microstrip leaky-wave antenna

A novel two-dimensional beam-scanning microstrip leaky-wave antenna (MLWA) is presented. The proposed antenna consists of two half-width MLWA with a phase-shifter. This new type of MLWA has the advantages of two-dimensional beam-scanning and suppressing back lobes. This reduced size MLWA is useful in automotive radar systems and air traffic control.     

TD—SCDMA移动通信基站电磁辐射的运行期环境影响预测与分析

浙江省的3G网络TD—SCDMA基站正在大量建设,本文通过选取在温州市已经运行两个TD—SCDMA基站的电磁辐射现状监测,对未建或在建基站的电磁辐射环境影响进行了预测与分析。由温州市两个已建基站的类比监测和分析可见,基站正常运行时对周围环境的电磁辐射贡献相对较低,类比监测结果均低于评价标准值;拟建基站对周围电磁辐射水平的贡献随与发射天线的距离增大而减小,若天线主瓣前方无遮挡物,则单个基站的电磁辐射贡献值能符合电磁辐射环境保护要求。     

Redundancy concepts to increase transmission reliability in wireless industrial LANs

Wireless LANs are an attractive networking technology for industrial applications. A major obstacle toward the fulfillment of hard real-time requirements is the error-prone behavior of wireless channels. A common approach to increase the probability of a message being transmitted successfully before a prescribed deadline is to use feedback from the receiver and subsequent retransmissions (automatic repeat request-ARQ-protocols). In this paper, three modifications to an ARQ protocol are investigated. As one of these modifications a specific transmit diversity scheme, called antenna redundancy, is introduced. The other modifications are error-correcting codes and the transmission of multiple copies of the same packet. In antenna redundancy the base station/access point has several antennas. The base station transmits on one antenna at a time, but whenever a retransmission is needed, the base station switches to another antenna. The relative benefits of using FEC versus adding antennas versus sending multiple copies are investigated under different error conditions. One important result is that for independent Gilbert-Elliot channels between the base station antennas and the wireless station the antenna redundancy scheme effectively decreases the probability of missing a deadline, in a numerical example approximately an order of magnitude per additional antenna can be observed. As a second benefit, antenna redundancy decreases the number of transmission trials needed to transmit a message successfully, thus saving bandwidth.