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缝耦合微带双贴片天线阻抗和辐射特性 总被引:1,自引:0,他引:1
本文提出了将阵列单元由单贴片改成缝耦合双贴片的形式。利用并矢Green函数和谱域矩量法分析了单贴片及缝耦合双贴片天线的输入阻抗。考虑了阵列天线的馈电网络中不均匀性的影响,根据解积分方程所得出的微带天线贴片表面电流分布。计算出其方向图特性,结果表明,缝耦合双贴片两单元微带阵列天线的阻抗频带提高到普通两单元微带阵列天线频带的2.5倍,文中实验数据与理论计算结果吻合甚好。 相似文献
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提出了一种利用多种形式的辐射贴片阵元组成的复合式阵列天线。阵元采用了多种形式的馈电方法。部分阵元和馈电微带线直接连接馈电,其他阵元和馈电微带线采用电磁耦合进行馈电。通过优化辐射贴片的形状、对应的馈电方法、辐射贴片连接端的阻抗调节块、阵列单元之间的阻抗调节段,在宽频带内不但获得了良好的阻抗特性,也实现了期望的赋形辐射方向图。测试结果表明,该阵列天线高度小于中心频率的0.06个波长,相对阻抗带宽(驻波比小于1.45)和辐射带宽分别超过23%和17%。 相似文献
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本文提出了一种新型的宽频带、高增益贴片天线,这种天线在频带内拥有良好的方向图特性。天线的频带范围
从1GHZ 到3.5GHZ,这个天线的尺寸是
0.9?0?0.9?0?0.14?0 ,阻抗带宽达到了111%(驻波比小于2)。设计的贴片天线
采用耦合馈电形式,天线在频带范围内方向图对称,没有出现裂瓣,最高增益达到10.5dBi,交叉极化在-20dB 以下。 相似文献
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讨论了有源相控阵面天线的波束扫描特性,用矩量法(MM)计算出互阻抗,激励电流及相应的辐射波瓣,提出了用互阻抗矩阵对天线进行去耦的方法,并用此方法进行实验,得出面天线的立体方向图和主磁面方向图,实验结果表明上控阵天线波束扫描角小于45°时,这种去耦方法是有效的,为实现超低副瓣相控阵面天线奠定了理论基础。该法还可以用于舰用共形阵天线的去耦。 相似文献
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A hybrid numerical technique is presented for a characterization of the scattering and radiation properties of microstrip patch antennas and arrays residing in a cavity recessed in a ground plane. The technique combines the finite-element and boundary integral methods to formulate a system for the solution of the fields at the aperture and those inside the cavity via the biconjugate gradient method in conjunction with the fast Fourier transform (FFT). By virtue of the finite-element method, the proposed technique is applicable to patch antennas and arrays residing on or embedded in a layered dielectric substrate and is also capable of treating various feed configurations and impedance loads. Several numerical results are presented, demonstrating the validity, efficiency, and capability of the technique 相似文献
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背腔式微带天线电磁散射分析的FEM/PO-PTD方法 总被引:3,自引:0,他引:3
将一种新的混合方法-FEM/PO-PTD方法,应用于分析计算背腔式微带天线的电磁散射特性。通过无穷大接地导体平面上矩形背腔式微带天线的RCS计算,验证了该方法的正确性。在此基础上,计算了两组有限尺寸金属载体上背腔式微带天线的RCS曲线,理论分析与计算结果表明,该混合方法具有计算机内存需求少、计算时间短等优点。 相似文献
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Jian Gong Volakis J.L. Woo A.C. Wang H.T.G. 《Antennas and Propagation, IEEE Transactions on》1994,42(9):1233-1242
An edge-based hybrid finite element-boundary integral (FE-BI) formulation using tetrahedral elements is described for scattering and radiation analysis of arbitrarily shaped cavity-backed patch antennas. By virtue of the finite element method (FEM), the cavity irregularities, the dielectric super/substrate inhomogeneities, and the diverse excitation schemes inside the cavity may be readily modeled when tetrahedral elements are used to discretize the cavity. On the aperture, the volume mesh reduces to a triangular grid allowing the modeling of nonrectangular patches. Without special handling of the boundary integral system, this formulation is typically applicable to cavity-backed antenna systems with moderate aperture size. To retain an O(N) memory requirement, storage of the full matrix due to the boundary integral equation is avoided by resorting to a structured triangular aperture grid and taking advantage of the integral's convolutional property. If necessary, this is achieved by overlaying a structured triangular grid on the unstructured triangular grid and relating the edge field coefficients between the two grids via two narrow banded transformation matrices. The combined linear system of equations is solved via the biconjugate gradient (BICG) method, and the FFT algorithm is incorporated to compute the matrix-vector product efficiently, with minimal storage requirements 相似文献
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The analysis of patch antennas residing in cavities filled by general inhomogeneous and lossy bianisotropic substrates is presented. The theoretical study is based on a variational formulation associated with the boundary value problem under analysis, and a hybrid finite element-boundary integral method is employed to solve the electromagnetic field inside and outside cavities numerically. Initially, the general formulation presented is applied to some particular cases known in the literature. Then, the main scattering and radiation features of cavity backed patch antennas with chiral, anisotropic, and bianisotropic materials are presented. Particularly, it is shown that complex media allow for frequency control and for a reduced antenna size at a given operating frequency. 相似文献
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The finite thickness of the ground plane is taken into account in the cavity model to analyse some aperture coupled microstrip patch antennas at millimetre-wave frequencies (60 GHz). The thickness has a strong effect on impedance matching at high frequencies owing to the ratio between the thickness and the wavelength, which increases with frequency. The calculated results are compared to those obtained by experiment for several antennas with different input impedances due to different slot lengths. Close agreement is found between the calculated and experimental results 相似文献
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Gérard Dubost 《电信纪事》1987,42(9-10):588-605
The transmission line model has been utilized to determine the input impedance, the bandwidth, the radiation patterns and the mutual impedance of several microstrip antennas such as the arbitrary shape patch antennas and the wideband flat dipole which is an hybrid radiating source. We suppose that the dominant mode of propagation is the quasiTem one having negligible variation of fields in the transverse direction. Nevertheless a general scattering problem of an arbitrary shaped tridimensional antenna solved by moments method and the finite difference approach applied to integral equations has explained the very large bandwidth microstrip antenna behaviour. The wideband flat dipole has been used in flat arrays, with more than several hundred of such elements, and in microstrip phased arrays with beam steering in a large angular sector. 相似文献
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Reddy C.J. Deshpande M.D. Cockrell C.R. Beck F.B. 《Antennas and Propagation, IEEE Transactions on》1996,44(10):1327-1333
A technique using the hybrid finite element method (FEM)/method of moments (MoM) and geometrical theory of diffraction (GTD) is presented to analyze the radiation characteristics of cavity fed aperture antennas in a finite ground plane. The cavity which excites the aperture is assumed to be fed by a cylindrical transmission line. The electromagnetic (EM) fields inside the cavity are obtained using finite element method (FEM). The EM fields and their normal derivatives required for FEM solution are obtained using: (1) the modal expansion in the feed region and (2) the MoM for the radiating aperture region (assuming an infinite ground plane). The finiteness of the ground plane is taken into account using GTD. The input admittance of open-ended circular, rectangular, and coaxial line radiating into free space through an infinite ground plane are computed and compared with earlier published results. Radiation characteristics of a coaxial cavity-fed circular aperture in a finite rectangular ground plane are verified with experimental results 相似文献
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Shafai L. Sharma S.K. Daneshmand M. Mousavi P. 《Antennas and Propagation, IEEE Transactions on》2006,54(5):1467-1473
In this paper, the far-field phase shift properties of microstrip patch antennas are investigated. It is shown that, similar to reflectarrays, the resonant nature of microstrip patches can be used to change the phase of the radiated field. This phase change can be caused by the dimensional change of the microstrip patch, or by a reactive loading of its cavity such as an aperture on its ground plane. However, the available phase shift is limited by the antenna impedance bandwidth. The problem is initially investigated for conventional patch antennas, determining the available phase shift range. It is then studied for a wideband E-slot microstrip antenna, showing a considerably larger phase shift range. Then, a micro-electro-mechanical (MEM) based ground plane membrane, activated by an electrode from below, is proposed to adaptively generate and control the required phase shifts. It provides a low loss, continuously variable phase shifter that can be used at high frequencies for beam scanning in small arrays. 相似文献
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A finite-difference time-domain (FDTD) analysis of spiral antennas is performed to calculate input impedance, antenna gain, and scattering. A semicircular spiral mounted on a dielectric substrate was simulated for computing the input impedance versus frequency. The gain and scattering computations were performed on a square Archimedean spiral mounted in a ground plane with a cavity backing. Total-field FDTD calculations are used to compute the impedance and gain patterns, while a specially modified scattered-field approach for aperture antennas in infinite ground planes is used for the scattering results. Comparisons are made with published impedance measurements and gain and scattering calculations done with a finite element method. Good results were obtained for impedance, radiation, and scattering 相似文献