同轴共线阵列天线低副瓣设计

对流层风廓线雷达对阵列天线的要求是结构简单,在满足高增益条件下,低副瓣是其关键指标。针对该应用背景,提出了一种辐射单元长度可变的同轴共线天线(COCO)模型。该天线模型利用不同数量辐射节COCO线源组阵,其口径幅度为修正Taylor分布。在该模型基础上,采用数值计算和优化,COCO阵列天线增益为25.7dB,E面副瓣为-23dB,H面副瓣为-22.3dB。该天线阵样品的测试表明,所设计的低副瓣COCO阵列天线完全达到了设计目标。

双锥共线阵天线辐射特性

双锥共线阵天线因其宽频带,高辐射功率等特点被广泛应用于工程中,文中采用基于有限元法的电磁场仿真技术对双锥共线阵天线进行辐射特性研究,分别通过改变阵子个数,锥角等参数研究其辐射特性与各参数变化的关系。然后根据导航设备的实际需要设计出一种满足国际民用航空公约附件十要求的双锥共线阵天线,实验结果表明,该天线适用于陆基导航系统中测距机的信标天线。

同轴共线阵天线分析及在干扰查找中的判别

同轴共线阵天线是一种广泛用于雷达、通信等领域的高增益全向天线。本文通过对该天线进行仿真,结合天线增益图和微波链路计算公式,得出与发射源不同距离、仰角的接收点电平值大小,最后给出徒步查找干扰源的建议。

介绍三种调频收音机天线

为了改善和提高调频收音机的接受效果,常常需要敷设天线。这里介绍三种用300Ω扁平馈线制作的调频收音机用天线。这三种天线制作简单,取材方便,可以布置在室内和室外,其效果也都优于机上所带的拉杆天线。

Ultra-wideband bilateral tapered slot-line antenna fed by coplanar waveguide

In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.

Coordinated Resource Allocation for Satellite-Terrestrial Coexistence Based on Radio Maps

Coexistence of satellite and terrestrial wireless communication systems in the same frequency band is quite promising for addressing the challenge of spectrum scarcity. To cope with the inevitable inter-system interference, radio resource allocation at both sides should be carefully re-optimized. In this paper, we focus on a scenario where a satellite communication system and a terrestrial distributed antenna system(DAS) coexist via spectrum sharing. We particularly utilize the radio map(RM) to reduce the system overhead for channel acquisition. Based on the large-scale channel state information at the transmitter(CSIT), which is derived from the RM, we propose an optimized power allocation scheme to improve the achievable sum rate of the terrestrial system. For the satellite side, an opportunistic user scheduling scheme is presented, to reduce the harmful leakage interference to the terrestrial mobile users. Simulation results demonstrate that the proposed RM-based coordination scheme can significantly promote the performance of satellite terrestrial coexistence, although the small-scale channel fading has been ignored in the formulated optimization.

Coordinated Multi-User Spectrum Sharing in Distributed Antenna-Based Cognitive Radio Systems

Spectrum sharing for efficient reuse of licensed spectrum is an important concept for cognitive radio technologies.In a spectrum-sharing system(SSS),deploying the antennas in a distributed manner can offer a new spatial dimension for the efficient reuse of licensed frequency bands.To improve the whole performance of multiple secondary users(SUs),this paper addresses the problem of coordinated multi-SU spectrum sharing in a distributed antenna-based SSS.By adopting the Hungarian method,the primal decomposition method and pricing policy,we propose a coordinated multi-user transmission scheme,so as to maximize the sum-rate of SUs.Simulation results show that the proposed method can significantly enhance the system performance,and the computational complexity is low.

互耦效应对天线阵单元间相关性的影响

分析了互耦效应对多天线性能的影响,通过网络等效分析法对天线模型进行简化分析,得出阻抗矩阵和收发端的耦合矩阵。推导出互耦效应时天线阵元空间相关性的通用表达式,并论证了它与无互耦时空间相关性的关系。研究了互耦效应分别对平行天线阵列和共线天线阵列阵元间空间相关性的影响。仿真分析表明,互耦效应对于两种天线阵列的影响显著不同,适当的选择天线阵列可以有效地改善互耦效应对于系统性能的影响。