一种圆柱共形的全向微带天线

提出了一种全向的圆柱共形矩形微带天线。阐述了这种在薄圆柱形介质基片上的矩形微带天线的分析方法和设计方法，并给出了理论和实验结果，证实了这种天线在垂直于柱体轴的平面内辐射出全向性的方向图。     

计算多介质层矩形微带天线谐振频率的解析方法

提出一种分析多介质层矩形微带天线的解析方法。首先导出了计算多介质层微带线的等效相对介电常数的显式计算公式，进而得到了多介质层矩形微带天线谐振频率的解析计算公式和一些数值结果。与精确的数值方法结果和实验值作了比较，它们吻合得很好。本方法运算简单，特别适合于ＣＡＤ应用。     

矩形微带天线的一种快速优化设计方法研究

针对矩形微带天线优化设计主要依赖经验和反复试验的现状,研究提出了一种矩形微带天线的快速优化设计方法。分析了传输线理论对矩形微带天线分析时的准确性,并将传输线理论成功地与改进的量子遗传算法(IQGA)相结合,应用于矩形微带天线的优化设计之中。利用该方法优化设计了一款矩形微带天线,通过将设计分析的结果与有限元软件HFSS计算结果比较,说明该算法的高效性及准确性。为方便该方法的应用,开发了一款矩形微带天线的快速优化设计软件包。     

微带电视频道天线设计和实物测试

微带天线结构的特殊性,使其在航天技术,通信领域受到重视。采用印制电路板的工艺制造方法,可以方便地将辐射器、全部功率分配器、匹配网络和移相电路光刻在介质板一侧,另一侧为接地板,就形成了微带天线。笔者以微带矩形片为振元,设计了电视ＣＨ４９频道微带天线,额定功率为５０ Ｗ。１ 矩形微带天线的辐射原理选用传输线模型分析方法来讨论矩形片微带天线辐射原理,如图１所示。设辐射元长度为Ｌ,宽度为Ｗ,介质基片厚度为ｈ。这样就可以将辐射元、介质基片和接地板视为一段长为Ｌ的低阻抗微带传输线,其两端形成开路。根据传输线理…     

矩形手征微带天线的辐射特性

本文首先建立了有覆盖层的矩形手征微带天线的数学模型，应用谱域导抗法得到了不同区域中的说域并矢格林函数，借助矢量法数据分析了手征介质的本构和几何参数，以及矩形贴片的几何形状等参量对微带天线的谐振频率和方向图的影响程序，发现了一些有趣的现象。     

层状磁电复合基板微带天线设计及应用

 本文提出一种新的小型化、宽频带微带天线.采用以层状磁电复合材料为基板的微带天线形式,推导了设计公式并给出计算结果.与介质基板矩形微带天线相比,该磁电复合基板天线的尺寸缩小了40%多,而带宽约为6%,是介质基板天线4倍.     

对L型宽频微带天线的改进

宽频带技术是微带天线研究的一个重要方向.依据矩形微带天线理论,设计了以空气做介质层,采用在脊形接地板顶端用同轴探针对单层方形贴片进行馈电的新型天线,目的是减小探针引起的电感,从而扩展了微带天线的工作频带.利用Ansoft HFSS软件对天线进行仿真和优化,并进行实物加工和测试,最后达到了天线设计的要求.     

空气隙对矩形微带天线性能的影响

论述了通过引入空气隙来改变矩形微带天线性能。首先,根据修改的微带天线的腔模理论,利用电磁场理论推导了具有空气隙的矩形微带天线的等效介电常数和谐振频率的理论计算公式。然后,考虑了边缘场的影响,引入了有效介电常数,对谐振频率的理论公式进行了修正。同时,应用等效原理和镜像原理推导出辐射方向图。最后,对于空气隙高度为不同数值的情况给出矩形微带天线的谐振频率和辐射方向图的数值结果,与文献实测结果很吻合。     

基于腔模理论讨论矩形微带天线远区场

微带天线具有剖面薄、体积小、重量轻、平面结构等特点,他可以形成与导弹、卫星等载体表面共形的结构,能与有源器件和电路集成单一的模件,便于获得圆极化波,实现双频段、双极化等功能。微带天线是由导体薄片粘贴在背面有导体接地的介质基片上形成的天线,利用腔模理论对矩形微带天线远区场求解时,将微带天线看作是一个矩形谐振腔,列出腔内波动方程,求出内场,利用Jm=n×eEz公式求出磁流,再利用矢量电位求出远区场和方向函数表达式。     

介质微扰对微带天线性能影响的研究

本文论述了在微带天线辐射缝隙附近,局部的介质基板对天线频率特性的影响.首先建立了一个以空气为介质,工作频率为2.45GHz的矩形微带贴片天线,并给出了天线的具体尺寸,在此基础上,在天线基板两辐射缝隙处增加了相对介电常数为εr的一小段矩形支撑介质,借助于微带天线腔模理论模型和麦克斯韦方程式对改变后的模型进行分析,得出了增加支撑介质后天线谐振频率与原谐振频率的关系,并利用HFSS仿真工具验证了公式在一定范围内是正确的.     

Superconducting microstrip antennas: an experimental comparison oftwo feeding methods

The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gas-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals     

Theoretical Investigation of the Input Impedance of Gap-Coupled Circular Microstrip Patch Antennas

In this paper, we have explored a simple theoretical input impedance computation technique for the two gap-coupled circular microstrip patch antennas by using circuit theory approach. The frequency characteristics of the input impedance of the two gap-coupled circular microstrip patch antennas with the gap-distance between the feed patch and parasitic patch is analyzed and simulated. The effect of feed location in the feed patch on the input impedance of proposed antenna is also studied. The theoretical results are compared with the simulated results as well as other reported literature. The simulation has been performed by using a method-of-moment based commercially available simulator IE3D.     

Analysis of circularly polarized square ring and crossed-strip microstrip antennas

Segmentation technique coupled with cavity model have been used to analyze square ring and crossed-strip microstrip patch antennas for circular polarization. This technique is found to predict the characteristics of antennas correctly, as is evident from the close agreement between the calculated and measured results for resonant frequency, input impedance, radiation patterns, and bandwidth. Square ring antenna has been found to have larger impedance bandwidth and axial ratio bandwidth because of lowerQ. Crossed-strip antenna has larger size and thus fabrication tolerances can be relaxed.     

Lens-coupled imaging arrays for the millimeter- andsubmillimeter-wave regions

The authors have been developing four kinds of lens-coupled antenna imaging arrays for operation at millimeter- and submillimeter-wave frequencies. Dipole antennas, Yagi-Uda trap-loaded antennas, and microstrip patches are compared from the viewpoint of matching with detectors and optical systems. The radiation patterns and input impedance of each antenna have been calculated and measured to attain the optimum matching using model experiments. The trap-loaded antenna arrays have been successfully applied to plasma diagnostics at the Tsukuba GAMMA 10 tandem mirror     

Feeding structure contribution to radiation by patch antennas withrectangular boundaries

A combination of piecewise sinusoidal-pulse functions and semi-infinite microstrip current expansion functions is used in the full-wave spectral-domain method to analyze microstrip antennas with arbitrary rectangular boundaries. Radiation properties are formulated in the spectral domain to achieve high numerical efficiency. Two types of microstrip antennas, edge-fed rectangular and inset fed patches, have been analyzed and measured. A line-reflect-line de-embedding algorithm has been implemented to measure the input impedance of both antennas. The results show good agreement between measurement and calculated data. The radiation patterns from the edge-fed rectangular patch are measured and are compared with the theoretical data. Results show that the current on the feed line can disturb the antenna radiation pattern     

Analysis of the annular-ring-loaded circular-disk microstripantenna

A rigorous analysis of the natural resonance frequencies and input impedance characteristics of an annular-ring-loaded (ARL) circular-disk microstrip antenna is presented. Using vector Hankel transforms, the problem is formulated in terms of vector dual-integral equations. Galerkin's method is then used to solve the equations to obtain the resonance frequencies and the current distribution on the conductive patches arising from a probe excitation. Due to the singular nature of the current distribution, the singularity subtraction method has been used to accelerate the convergence of basis function expansions. Experiments for determining resonance frequencies and input impedance characteristics of an ARL circular-disk microstrip antenna with various substrate thicknesses have been made. The theoretical results are in good agreement with the experimental data even when the thickness of the substrate is 0.1 substrate wavelength. It is shown that this theory can be used to analyze some microstrip antennas with an electrically thick substrate, including the analysis of mutual coupling between conductive patches or between the path and the feed of a microstrip antenna     

A modified contour Integral analysis for Sierpinski fractal carpet antennas with and without electromagnetic band gap ground plane

A modified contour integral method coupled with segmentation method has been used, for the first time, to analyze both the Sierpinski fractal carpet (SFC) antennas of different orders and an SFC antenna with electromagnetic band gap (EBG) ground plane. The close agreement between the calculated and measured results for resonant frequencies and input return losses indicates that this technique can be used to accurately predict the impedance characteristic. A novel stacked microstrip Sierpinski carpet fractal antenna using the EBG ground plane is also presented. Comparing to an ordinary microstrip fractal antenna, which has a maximum bandwidth of approximately 2%, the proposed antenna has a higher input impedance bandwidth of nearly 9%. The radiation patterns of the proposed antenna are improved due to the removal of unwanted radiation caused by the surface wave. The experimental measurement results of the proposed antenna are presented in this paper.     

高温超导微带天线的谐振特性研究

传输线模型是分析微带天线的一种最简单的方法,但其未将导体的特性参数考虑到天线的分析中去,针对这一缺点,为研究超导体的表面阻抗对高温超导微带天线输入阻抗和谐振频率的影响,把导体特性对天线的影响看作一种微扰来处理,对传统的传输线模型进行了修正,并通过与谱域矩量法相比较,验证了修正后方法的有效性.进而利用修正后的方法计算分析了高温超导矩形微带贴片天线的输入阻抗和谐振频率,给出了关于高温超导微带天线输入阻抗和谐振频率的若干结论.     

Analysis of arbitrarily shaped microstrip patch antennas using segmentation technique and cavity model

Arbitrarily shaped microstrip patch antennas have been analyzed for resonant frequency, input impedance, and radiation patterns. The segmentation technique and the cavity model have been used for this purpose. The usefulness and the accuracy of the method are shown through comparison with experimental results for a rectangular ring antenna. The agreement is seen to be very good. Ihe method appears to be more efficient compared to those reported so far for arbitrary shapes. Moreover, feed reactance is built into the analysis. The method presented here can also be used to analyze microstrip antennas with various types of loadings, e.g., shorting pins, matched loads, etc.     

Novel design of broad-band stacked patch antenna

A novel broadband stacked E-shaped patch antenna is proposed in this paper. The proposed antenna has an input impedance bandwidth of about 38.41%, better than the conventional E-shaped microstrip patch antenna, which has an input impedance bandwidth of 33.8%. Through the use of the washer on the probe of the stacked patch antenna, the input impedance bandwidth is improved further to 44.9%. The radiation patterns are found to be relatively constant throughout the whole band. Comparisons of these antennas are presented in this paper.