A novel wideband antenna design using U-slot

U-slot patch antennas with П-shaped feed slot are studied, and numerical results based on the FDTD method are presented. The effects of varying physical parameters are investigated with a goal of understanding the coupling among different resonators. It is found that the U-slot patch antenna can be designed to attain 50% impedance bandwidth as well as 30-40% gain bandwidth. By altering the sizes of U-slot and feed slot, the wideband characteristic can be changed into a duai-frequency char- acteristic.     

A combined full-wave BCG-FFT method for radiation of microstrip antenna arrays

A method of combining BiConjugate Gradient(BCG) with Fast Fourier Trans-form(FFT) to analyze the radiation of microstrip antenna arrays is presented, where the spatially discrete BCG-FFT for analyzing microstrip structure is used and the del operators on Green's functions are transferred from the singular kernel to the expansion and testing functions. The resultant equations are solved by using BCG method in which the matrix-vector product is evaluated efficiently with FFT. The calculated patterns are in good agreement with the measured data.     

宽带微带贴片天线的研究进展

文章论述了微带贴片天线频带展宽方面的研究进展,主要介绍了几种新型的大带宽微带贴片天线。这些天线采用了在贴片或接地板“开窗”,附加负载,增加片元等方法来改进微带贴片天线的窄频特性,同时使其向小型化,结构简单化方向发展,使微带贴片天线的应用范围得到进一步的扩大。     

FDTD法计算铁氧体微带天线的RCS

该文采用并改进了一种将铁氧体进动方程直接离散的更有效的FDTD算法,在结合其它FDTD算法中的新技术基础上分析计算了任意方向外加偏置磁场时铁氧体矩形微带贴片天线的RCS频响特性并给出了一些有用的结论。     

曲线分段的矩量法分析阿基米德平面螺旋天线

从混合位积分方程出发,采用矩量法结合曲线分段的三角基函数和脉冲检验函数分析了阿基米德平面螺旋天线,给出了输入阻抗,电流分布以及辐射方向图结果.从曲线形式的海伦积分方程出发结合折线分段的脉冲基函数点匹配法比较结果与文献[2～4]十分吻合.由于采用了曲线分段,在相同分段数情况下其结果的精度将比采用折线分段的高.     

Efficient analysis of electromagnetic radiation from microstrip antenna using volume-surface current contunuity method

The Volume-Surface Current Continuity Method (VSCCM) is presented to analyze electromagnetic radiation from microstrip antenna. The microstrip antenna is discretized into small triangular patches on conducting surface and tetrahedral volume cells in dielectric region. The Method of Moments (MoM) is applied to solve the integral equation. An equation contains the restriction relation between the volume and surface current coefficient is derived from the current continuity equation at those parts where the conducting surface is in contact with the dielectric material. A simple equivalent strip model is introduced in the treatment of the feeding probe in VSCCM. The VSCCM can reduce the unknowns required to be solved in MoM, as well as the condition number of the matrix equation. Numerical results are given to validate the accuracy and efficiency of this method.     

Millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip antenna

A millimeter-wave waveguide-based out-of-phase power divider/combiner using microstrip patch antenna has been proposed in this paper. The stepped rectangular waveguide provides smooth impedance matching from standard rectangular waveguide to oversized rectangular waveguide. In order to obtain good amplitude balance, four symmetrical microstrip patch antennas are utilized. A Ka-band four-way passive power combiner is designed and measured. The measured results show a reasonable agreement with the simulated ones.     

FDTD中微带线激励源设置的新方法

ＦＤＴＤ已广泛应用于微带问题的计算中,本文提出了一种新的微带线馈电激励设置方式,同以往的激励设置方法不同,它不仅能计算Ｇａｕｓｓｉａｎ脉冲激励也能计算正弦波激励,计算过程中,源平面无需切换成吸收边界,场区的划分使反射场自然从总场区分离出来。     

Analysis of Modified Square Sierpinski Gasket fractal microstrip antenna for Wireless communications

In this paper, the slot loaded microstrip antenna has been developed with Sierpinski gasket technique. The proposed Modified Square Sierpinski Gasket (MSSG) fractal antenna involves a square patch utilizing Sierpinski gasket (triangular) structure. Four triangular slots are loaded at each iteration. The structure is then simulated using commercially available Ansoft HFSS simulator. The multi-band operation has been achieved by the proposed antenna at 15.915 GHz, 20.045 GHz, 23.077 GHz, 27.77 GHz frequencies with −20 dB, −25 dB, −22 dB, −28 dB return loss respectively which works well for Ku (12–18 GHz) and K (18–27 GHz) band. The consistent result is obtained after simulation and the validity of fabricated design is checked by the measured result. The designed antenna is an attractive candidate for applications like wireless multi-band communication systems.     

多层微带贴片天线单元和阵列设计

该文通过结合经验公式和全波分析法,设计了一种电容补偿双层贴片、四层介质的微带贴片天线单元,该单元天线在频率为995～1125MHz的范围内,在驻波比SWR1.5的情况下,相对阻抗带宽达到12.26％的工程要求。此外,该文给出由该单元天线组成的216天线阵以及天线阵的驻波比的实测结果,最后给出天线阵的各单元排列方式和单元之间的互耦特性曲线的实测结果。     

口径积分法结合CST软件分析缝隙阵列天线罩

采用近场口径积分算法结合三维电磁仿真软件(Computer Simulation Technology,CST)仿真软件分析了带有多层介质天线罩的平板缝隙阵列.用CST对天线罩内的缝隙阵列天线进行仿真分析得到每个缝隙中心点的电磁场分布,对天线罩部分分析采用近场口径积分法分析天线罩部分对平板缝隙阵的影响.通过对该混合方法计算出的带罩平板缝隙阵列天线结果与CST全波仿真结果进行对比来验证该方法的正确性,结果表明:两者吻合很好.由于采用CST软件提取缝隙阵口径场考虑了阵元之间的互耦,较传统的理想阵元模型更加准确.混合方法避免了全波算法解决电大尺寸多层介质天线罩分析过程中耗费计算资源大、时间长的缺点.     

角馈微带天线的全波分析

利用积分方程法对角馈型微带天线进行了分析,对其中的奇异振荡函数积分,给出了有效的数值积分方法。数值实验证明了该方法的有效性。同时,给出了角馈微带天线的输入阻抗特性,方向图特性和带宽特性。     

Performance enhancement of a compact wideband patch antenna array using EBG structures

In this paper, a compact wideband linear microstrip phased array antenna (MPAA) is proposed. To reduce the size of MPAA, a compact wideband aperture coupled microstrip patch antenna (MPA) is utilized as array element. Size reduction of the array element is performed through incorporating an interdigital capacitor (IDC) in the patch and a metamaterial (MTM) unit cell close to slot in the ground plane of the antenna. By cutting two vertical slits from the slot, further compacting of the slot in the ground plane of array element is obtained. By this technique dimensions of the patch and slot are reduced by 12.9% and 12.2%, respectively. Furthermore, dimensions of the MPAA are reduced through decreasing the spacing between array elements causing the antenna performance degradation. To overcome this shortage and improve the radiation characteristics of the proposed MPAA, an electromagnetic bandgap structure (EBG) is utilized. The effect of implementing EBG cells on the reflection coefficient of the elements in the MPAA during beam scanning is studied in details. The maximum measured gain, bandwidth and cross-polarization level of the fabricated MPAA are 13.3 dBi, 24.4% and −40 dB, respectively making it a good candidate for monopulse tracking radar applications. The measurement results confirm the simulation results.     

隧道二极管在放大电路中的应用

详细介绍了隧道二极管的特性和负阻产生的机理，分析讨论了隧道二极管并联放大器的静态特性、主要性能指标和偏置要求。根据研究结果，完成了电路元件的参数选择。通过计算机仿真，获得满意的结果。对隧道二极管的应用具有一定的指导意义。     

Resonant characteristics of aperture type FSS and its application in directivity improvement of microstrip antenna

In this paper, we propose an aperture type frequency selective surface (FSS) by employing an array of 12 × 12 unit cell elements and its resonant characteristics is analyzed. A resonant cavity antenna is then formed by the ground plane substrate and the FSS superstrate. The high reflective behavior of the proposed FSS at an offset of the resonance is then utilized for improving the performance of this cavity antenna. The impedance bandwidth and directivity are improved up to 0.66 GHz and 8.95 dBi, simultaneously at an optimum gap of 17.6 mm between the antenna substrate and FSS superstrate. For validation purpose, prototypes of both patch antenna and FSS, are fabricated and characterized. A fairly good agreement is achieved between the measured and simulated results.     

基于调节转移技术稳定激光二极管的频率

阐述了利用调节及转换技术稳定激光二极管发射器的频率 ,这种发射器可以发射纳米波长的激光。通过分析两个相互独立的激光器系统中存在的振动信号 ,知道该振动信号已揭示了在 0 .0 9秒的时间内有 10 - 1 1 秒的时间频率是相对稳定的 ,并且在 1秒的时间内似乎可以得到 10 - 1 2 的最低干扰频率。为避免产生共振 ,充分吸收铯元素的D2 线作为频率参考及非线性光谱研究     

超宽带微带天线的波概念迭代法分析

随着无线通信系统的快速发展,具有宽带宽、增益高、尺寸小的超宽带微带天线受到广泛的关注。利用波概念迭代法(WCIP)结合传输线理论仿真了双层和三层结构的超宽带微带贴片天线,计算了该天线的回波损耗、驻波比等参数;对比分析了WCIP在计算效率上的优势;分析了电路层数对天线带宽的影响,发现增加电路层数是天线带宽展宽的一个有效途径。同时,与软件HFSS仿真结果的对比验证了WCIP分析微波多层电路的正确性和有效性。     

双偏置格里高利天线赋形方法的研究

针对双偏置格里高利天线的赋形技术进行了研究, 给出了一种双偏置格里高利天线的赋形方法.通过全微分条件推导出了副反射面和主反射面的映射关系, 并结合能量守恒定律、反射定律和等光程条件, 求取天线主、副反射面的轮廓曲线.最后给出了一个设计实例, 仿真结果表明:利用文中的赋形方法能够有效控制口面场幅度分布, 实现预期的天线方向图.     

双极化方形微带天线的阻抗特性

在方形微带贴片的相邻两边电可以辐射双极化波。文中结合平面电路技术,腔模理论,用Ｇｒｅｅｎ函数法导出了双边馈电方形微带天线输入阻抗与互阻抗的计算公式,分析了Ｘ波段双极化方形贴片天线输入阻抗,Ｓ参数和电压驻波比在谐振频率附近的变化情况,以及馈电点位置与宽度和εｒ对这些特性参数的影响。文中的计算方法可靠而简捷,可用于此类天线的设计,这种天线容易形成阵列结构,并易于有源集成。     

An iterative adaptive multi-modal stereo-vision method using mutual information

We propose a method for computing disparity maps from a multi-modal stereo-vision system composed of an infrared–visible camera pair. The method uses mutual information (MI) as the basic similarity measure where a segment-based adaptive windowing mechanism is proposed along with a novel MI computation surface with joint prior probabilities incorporated. The computed cost confidences are aggregated using a novel adaptive cost aggregation method, and the resultant minimum cost disparities in segments are plane-fitted in their respective segments which are iteratively refined by merging and splitting segments reducing dependency to initial segmentation. Finally, the estimated disparities are iteratively refined by repeating all the steps. On an artificially-modified version of the Middlebury dataset and a Kinect dataset that we created in this study, we show that (i) our proposal improves the quality of existing MI formulation, and (ii) our method can provide depth comparable to the quality of Kinect depth data.