“飘带”式喇叭天线特性研究

基于TEM喇叭天线的结构特点,兼顾天线辐射性能和轻量化考虑,设计了一种“飘带”式喇叭天线,该设计用两根弯曲的窄带代替了基本模型中的上板。针对“飘带”式喇叭天线的一些重要物理尺寸,利用Ansoft HFSS仿真软件对模型进行了分析。结果表明,该结构进一步改善了喇叭天线的低频性能,展宽了天线的频带。最后分析了“飘带”式喇叭天线的各个参数与天线性能之间的关系,得到了一组优化结果。     

基于3D打印技术的梯形凹槽双脊喇叭天线

该文提出了一种带有梯形槽的双脊喇叭天线,天线在口径面和外侧壁引入梯形槽结构,抑制了喇叭外壁上的电流,从而达到降低喇叭天线旁瓣的目的。天线采用3D打印技术,有效地解决了传统方式加工难及一致性差的问题。仿真和实测表明,该天线设计可有效提高天线增益,在工作频带5～10 GHz内天线增益大于10.32 dBi,回波损耗小于-10 dB;在9.6 GHz时峰值增益可达14.61 dBi。将天线喇叭壁设计成空心结构,天线质量减小了74%。测试结果与仿真结果基本一致。     

用FIT方法设计的宽频带双脊圆喇叭天线

采用有限积分技术(FIT)设计了一种1GHz～6GHz的宽频带双脊圆喇叭天线.调整天线各部分的结构尺寸,使天线的驻波比达到最小值,计算了它的增益、方向图等天线参数,并将它们和广泛用于电磁兼容测试的宽频带双脊角锥喇叭天线的电参数进行了对照,结果表明该天线比双脊角锥喇叭天线在吸渡材料拱形法测试当中有更大的优越性.对制作出的天线的电参数实测,结果和计算结果基本吻合.     

一种双频段圆锥喇叭天线的设计

介绍了一种双频段圆锥喇叭天线的设计.作为星载阵列天线单元的圆锥喇叭天线需要满足20/30 GHz双频段工作的需要.此处采用在光壁圆锥喇叭内加载一个外形渐变的金属柱体来改变天线的输入阻抗,调节金属柱体的尺寸,包括两端的口径和长度,可以在要求的频段得到理想的输入阻抗.仿真分析和实验测试结果说明该天线具有满意的频带特性和方向图特性.     

一种用于毫米波双向通信的波导喇叭天线设计北大核心CSCD

毫米波由于方向性强，要实现在同一直线上的前后向通信，通常采用功分器+双天线的方式。为进一步实现集成化，本文提出了一款将波导功分器和双矩形波导喇叭天线进行集成设计的波导喇叭天线。首先，根据波导的两级阻抗变换设计T型宽带波导功分器；然后，根据最佳角锥天线公式完成对矩形喇叭天线设计仿真；最后，将波导功分器和双矩形形喇叭天线按工程应用进行集成设计建模仿真。仿真结果表明该双向天线最大增益为22.48dBi，在71-86GHz的频带内S11优于15dB。除此之外，本次设计的波导喇叭天线具有结构简单、尺寸小、加工容易等优点，通过合理地集成到宽带通信设备中，可满足货运铁路准线性区上下行的双向无线接入。     

一种高功率多模喇叭天线

为满足高功率微波系统对天线的需求,设计了一种覆盖15.9~21.8 GHz频带的多模喇叭天线,并研究了其高功率性能。仿真计算表明,该喇叭天线在频带内驻波＜1.2,并具有良好的辐射特性。在16.3~20.8 GHz满足E面和H面方向图在20 dB范围内等化度良好,且喇叭输出功率达526 MW时不会出现击穿现象。     

一种末端加载型300MHz/1GHz双频车载超宽带探地雷达天线设计

为满足高速铁路无损探测需兼顾低频探测深度与高频探测精度的要求,采用理论计算与软件仿真结合的方法,设计制作了一种双频带(300MHz/1 GHz)指数型TEM喇叭天线并对其进行了测量。所设计的指数型TEM喇叭天线采用末端加载和适当天线臂切削来实现此超宽带天线的双频带工作。仿真与实测结果表明,天线分别工作在中心为360MHz、带宽约为110MHz的低频带和中心为1 020MHz、带宽约为260MHz的高频带,相对带宽均大于20%。实测天线的接收信号保真度较高,拖尾持续时间短,满足设计要求。此外,这种双频带天线系统可减少雷达系统天线和采样盒等设备的使用数量,降低雷达系统的成本,有较好工程应用前景。     

0.2～2 GHz宽带双脊喇叭天线的设计

双脊喇叭天线作为一种重要的宽带天线,在电磁兼容性测试中的应用越来越广泛。本文采用软件仿真设计了一种0．2～2GHz的双脊喇叭天线。通过仿真计算优化了天线各部分的尺寸,计算了天线的驻波比、增益和方向图等参数。对制造出的天线的参数进行实测,结果和仿真结果基本吻合。     

低频补偿TEM喇叭天线的仿真与测试

以超宽带窄脉冲辐射为应用背景,通过添加补偿回路并调整回路的大小,设计了一种具有低频补偿的超宽带TEM喇叭天线.利用FDTD方法对天线结构进行了仿真,分析了不同补偿回路大小时TEM喇叭天线的S11参数、相位特性、辐射带宽及前后向辐射场等参数,得到了在大于400 MHz频带范围内S11参数低于-10 dB的天线结构.制作天线原型,并进行了实际测试,频域S11参数测试结果与仿真结果基本吻合.通过对时域波形的分析可知,该天线具有较高的波形保真度.     

1～18GHz宽带双脊喇叭天线的分析及仿真

本文研究了同轴线馈电的1～18GHz的宽频带双脊喇叭天线。分析发现，与通常的看法不同，喇叭天线辐射方向图并不能在全频带上保持轴线方向具有单一的主波瓣。实际上，在12GHz以上，辐射方向图的主瓣开始分裂为偏离轴线方向的四个较大的旁瓣，且相对主瓣电平旁瓣电平低6dBC。喇叭天线是较为理想的测试天线，这方面的应用已经有四十多年的历史，但是对这一非理想特性的解释，未见公开文献发表。为了深入研究这一现象，运用矩量法仿真分析了整个天线系统。仿真结果与1～18GHz频带上的测量值非常吻合，由此表明在EMC的应用中，使用这种型式的喇叭天线还存在一定的问题。     

Efficiency measurement of UWB antennas using time reversal in reverberation chambers

Using the reverberation chamber to obtain antenna radiation efficiency is considered. The reverberation chamber, which has for many years been used for electromagnetic compatibility measurements, can also be used with great advantage for antenna measurements since it simulates effectively a uniform multipath propagation environment. How a reverberation chamber can be used to measure the ultra-wideband (UWB) antenna efficiency in a very short time is described. The procedure based on time domain is described and some experimental results are given and compared to measurements obtained by the Wheeler cap method extended by Schantz to UWB antennas.     

搅拌器配置对混波室场影响的FDTD分析

混波室能提供统计均匀和各向同性的场,是一种用于辐射发射、屏蔽效能及敏感度测试等电磁兼容测试的小室。本文用FDTD方法分析混波室的场分布,分析了搅拌器不同大小及不同倾斜角度对混波室时间平均场分布的影响,为实际设计混波室的搅拌器提供参考。最后给出了与数值分析相一致的实验结果。     

镜像对称结构对多馈源混响室场性能的影响

为解决混响室大体积与场性能高要求之间的矛盾,提出了一种基于镜像原理的多馈源混响室的设计思想,从原理上分析了镜像多馈源混响室的可行性和有效性,并通过仿真计算研究了镜像双馈源混响室的场性能.结果表明,在输入功率一定时,两个单混响室系统组合成镜像双馈源混响室后,在工作区域的场均匀性能不下降的基础上,不但可用于电磁兼容测试的工作区域体积大幅度增大,而且测试区域的电场强度也得到了提高.同时,对镜像多馈源混响室进行了进一步的扩展分析,得出了组成镜像多馈源混响室的单混响室系统数量的理论表达式.     

Power transfer characteristics of a microwave reverberation chamber

Power transfer through a microwave reverberation chamber is studied theoretically and experimentally. Two configurations are employed as follows. In the first, the chamber contains a transmitting antenna and a receiving antenna; in the second, it contains a transmitting antenna and a receiving D-dot sensor. For each configuration a theoretical model is derived and laboratory measurements are carried out for the power gain of the chamber as a function of frequency. The models prove useful in predicting the observed variation of gain with frequency, and they provide insight into the importance of power flow to the chamber walls and to the receiving antenna/sensor     

混响室法欠模状态屏蔽体屏蔽效能测试技术研究

欠模状态下屏蔽壳体内部场分布不均匀,屏蔽效能测量结果与位置相关,因此需要利用探头或单极子天线进行多位置测量,过程繁琐。文中利用长线天线来测量欠模状态下屏蔽壳体屏蔽效能,并与单极子天线测量结果进行比较。在暗室中测量天线自由空间反射系数S₁₁;在混响室中利用不同天线测量屏蔽壳体的屏蔽效能,并利用S₂₂分析腔体谐振特性。测量结果表明,长线天线宽频带匹配特性优于单极子天线,测量的屏蔽效能能够更好地反映屏蔽体谐振特性,为屏蔽壳体的屏蔽效能测试评估提供了指南,具有工程应用价值。     

A closer look at reverberation Chambers - 3-D Simulation and experimental verification

This paper presents three-dimensional (3-D) full-wave simulations of the electromagnetic field inside a medium-sized reverberation chamber. A frequency-domain method-of-moments approach based on the electric field integral equation is used. A synopsis of the computational challenges particular for reverberation chambers is described and a detailed overview on the chamber modeling procedure is given. The electric field inside the chamber is computed and the influence of small geometric details and asymmetries is investigated as well as the effect of different excitations and stirrers. It is demonstrated that a statistics-based validation of reverberation chamber simulations is insufficient. To validate simulation results, therefore extensive near-field measurements inside the prototype reverberation chamber are performed. The complete 3-D reverberation chamber simulation, considering stirrers, door, and various practical excitations, accurately predicts the fields within the chamber in the important lower-to-medium frequency range and thus represents a reliable tool facilitating reverberation chamber optimization.     

Validation of a Three-Dimensional Transmission Line Matrix (TLM) Model Implementation of a Mode-Stirred Reverberation Chamber

Reverberation chambers are attractive electromagnetic compatibility test facilities, both economically and technically. Careful design and analysis of these facilities are important, if the results obtained are to be treated with a high level of confidence. Numerical modeling is an important part of the process of reverberation chamber design and analysis. Hence, it is important that the modeling techniques to be used are appropriately validated. Much of the published work to date takes either a statistical or a deterministic view of validation. This paper provides validation evidence for a low-resolution transmission line matrix (TLM) model of a reverberation chamber in a manner approximating the way in which the chamber is used, i.e., validating based on the effects of a simple device under test. A variety of statistical and heuristic approaches have been used to quantify the level of agreement, intending to set the likely lower bound for the quality of comparisons between simulations and measurements. While not drawing any "universal" conclusions about the veracity of the TLM technique, the paper concludes that a relatively simple model of a reverberation chamber provides a useful analysis of the chamber with close comparisons between modeled and measured data.     

Design and construction of a multipurpose wideband anechoic chamber

An electromagnetic anechoic chamber has been constructed at the Multimedia University. It is designed to operate over a very wide frequency range from 30 MHz through 18 GHz. It can be used for electromagnetic compatibility (EMC) tests, antenna measurements, radar cross section (RCS) measurements, testing RF transceivers, calibration of scatterometers, and other electromagnetic research experiments. The geometry of the chamber is asymmetrical, consisting of a combination of rectangular and tapered volumes. The size of the chamber is about 64 ft /spl times/ 32 ft /spl times/ 24 ft high. Ease of construction and ease of lining of the absorbers were preserved so that the actual quietness is comparable to the theoretical simulation result. The transmitting source is placed at one end of the chamber, and the receiving antenna or object under test is placed in a designated quiet zone at the other end. The walls and ceilings are configured such that no first-order and or second-order reflections (except those reflected from the floor) propagate into the quiet zone. Hence, less-expensive absorbers can be used to achieve the required wideband performance. Reflection from the floor is required by the international EMC standards for radiated electromagnetic interference (EMI) emission tests; therefore, the chamber is designed for this capability. However, absorbing material can be placed on the floor to convert a semi-anechoic chamber into a fully anechoic chamber for radar and antenna measurements.     

Short axial length broad-band horns

Ever-increasing antenna frequency bandwidth requirements for countermeasures applications and electromagnetic compatibility measurements have provided the impetus for the development of a series of very broad-band horns. In addition to the broad bandwidth, a substantial reduction in axial length over that of earlier models has been achieved for the two designs discussed in this communication. The first horn described covers the frequency range from 1.0-12.0 GHz with the flared portion of the horn having an axial length of 6 in as compared with 12 in for an earlier model. Although horn antennas are not commonly considered for use at frequencies as low as 0.2 GHz, the short axial length design appeared to be an attractive approach in developing a very reasonably sized antenna operating in the 0.2-2.0 GHz range. The technique of fabricating theHplane walls in the form of a grid was used in both designs as a means of maintaining the requiredH-plane half-power beamwidths. The grid for the 1.0-12.0 GHz horn is of printed circuit form while the grid elements of the lower frequency horn are made of aluminum tubing. Electrical characteristics of both designs are presented, as well as some additional data for recent advances which indicate that a further reduction in axial length or an increase in bandwidth can be achieved with only a moderate rise in VSWR in the lower portion of the frequency range.     

一种K频段宽带双极化滤波喇叭天线设计

文中设计了一种K频段宽带双极化滤波喇叭天线,该天线采用阶梯型喇叭代替传统喇叭提升了天线效率,并通过在馈电波导冗余空间中引入一种T/Π型滤波结构,提升了天线带外的抗干扰能力. 仿真和实验结果表明,该双极化天线的?10 dB阻抗带宽超过5 GHz,覆盖了K/Ka频段卫星的下行频段,天线效率超过58%,并在其上行频段实现了超过33.1 dB的带外抑制,该天线可作为单元用于K/Ka频段卫星下行频段的大型阵列天线设计.