共查询到20条相似文献,搜索用时 15 毫秒
1.
《Electronics letters》2008,44(25):1444-1445
The design and analysis of novel hybrid-mode soft and hard horn antennas with a low index metamaterial wall liner are presented. Metamaterial horn antennas have the potential for considerably larger bandwidth than the current state-of-the-art horns. The optimal or required metamaterial dispersion curve for these horns is qualitatively similar to the Drude dispersion, which indicates that the metamaterial horns are realisable. 相似文献
2.
A novel typed of hybrid-mode feed horn is presented. It comprises a hollow conical dielectric waveguide whose outer surface is metallized, and whose inner surface is coated with circumferentially oriented conducting strips. It may be designed to have mimimal cross polarization at two arbitrarily separated frequencies, as for a dual depth corrugated horn. Compared to the corrugated horn, it has the potential of lower weight and lower price. Small horns will have some cross polarization due to undesired radiation from the fields transmitted within the dielectric. 相似文献
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Beniguel Y. Berthon A. Klooster C.V. Costes L. 《Antennas and Propagation, IEEE Transactions on》2005,53(11):3540-3546
We report on the design and realization of horn antennas required to achieve high performances with respect both to the return loss and the cross polarization level over a wide band. 相似文献
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For specified bias conditions, measurements and theory justify the first-order representation of an enhancement-mode MOS transistor operating with forward source-substrate bias (‘hybrid-mode’ operation) as a parallel combination of two non-interacting devices—an MOS transistor with zero source-substrate bias, and a bipolar junction transistor. 相似文献
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设计了一种带有机玻璃天线罩的地平板结构横电磁波(TEM)喇叭接收天线,通过对馈入结构和辐射特性的理论分析初步确定关键结构尺寸,然后利用CST建立天线真实模型,完成相关结构参数的仿真优化,实现了快脉冲的较小馈入反射,时频特性良好。最后的天线测试结果表明,该TEM喇叭天线输入阻抗56 Ω,有效高度0.024 m,传递函数在3 GHz以内保持稳定,具备较好的时域保真度和馈入反射特性,适于作为超宽带接收天线。 相似文献
6.
The body current IB of deep submicron lightly doped drain pMOSFETs has been investigated. Based on the experimental results, an analytical IB model, applicable for devices operating in a Bi-MOS hybrid-mode environment, has been developed for the first time. The proposed model is able to effectively characterize the measured IB results over a wide range of independently applied biases (gate, drain and body) and gate lengths (from 1 μm down to 0.25 μm). The possibility of minimizing or even eliminating the undesired IB is also explored and discussed for the first time. 相似文献
7.
Skobelev S.P. Bon-Jun Ku Shishlov A.V. Do-Seob Ahn 《Antennas and Propagation Magazine, IEEE》2001,43(1):90-93
We have carried out the optimization of the simplest dual-mode horn that does not include the special cylindrical phasing section. Calculation of the horn characteristics has been performed by using a stepped representation of the conical section, with a subsequent application of the method of generalized scattering matrices, which more accurately accounts for all of the effects taking place when exciting the horn, The objective of the optimization has been the minimization of the maximum crosspolar level. The optimum horn parameters obtained as a result, and the corresponding radiation characteristics, can serve as additional reference information in the development of antenna systems using dual-mode horns 相似文献
8.
Robert W. Haas Dennis Brest Harry Mueggenburg Lee Lang Dave Heimlich 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(11):2289-2294
Future spaceborne millimeter and sub-millimeter wave sensing systems will require the sensitivity and resolution only achievable with large focal plane array receiving systems. A technique has been developed for the low cost fabrication of large arrays of millimeter and sub-millimeter wave corrugated feed horns. These arrayed horns exhibit high efficiency and symmetrical receiving patterns and are compatible with integrated receivers. W-band test results of a 3×3 array are presented. 相似文献
9.
The simultaneous but independent development in the United States and Australia of circular-aperture corrugated horns in the early 1960's is reviewed. The features of this development include the wide flare-angle corrugated "scalar" horn and the characteristics of focal-region fields of reflector antennas and the single- and multimode cylindrical corrugated horns necessary to feed them. 相似文献
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11.
Bersanelli M. Bensadoun M. De Amici G. Limon M. Smoot G.F. Tanaka S. Witebsky C. Yamada J. 《Antennas and Propagation, IEEE Transactions on》1992,40(9):1107-1109
A large rectangular horn antenna with a center frequency of 2.0 GHz, corrugated on the E -plane walls, made out of aluminium sheet, has been designed, constructed, and tested. A technique has been developed to solder thin aluminium strips onto the back plane to form the corrugations. The radiation beam pattern shows half-power beamwidths of 12° and 14° in the H - and E -planes, respectively, and sidelobe response below -40 dB at angles greater than 50° from the horn axis. The measured return loss is greater than 20 dB (VSWR<1.22) between 1.7 and 2.3 GHz; insertion loss is less than 0.15 dB 相似文献
12.
Gonzalo R. Teniente J. del Rio C. 《Antennas and Propagation, IEEE Transactions on》2002,50(11):1505-1513
A new horn antenna profile is presented. This new profile based on Gaussian techniques offers the best solution when the requirements related to the radiation pattern are very stringent. Short-horn antennas with high-conversion efficiency to a fundamental Gaussian beam, and therefore, very low sidelobe and cross-pol levels in a wide-frequency band, could be obtained by using the design technique presented here. Once the theoretical principles of the Gaussian profiled horn antennas (GPHA) are presented, some other possibilities involving Gaussian profiles are studied and compared with their conventional counterparts. Finally, as an example of the design technique proposed, a particular design of a GPHA for HISPASAT 1C and now also valid for the new HISPASAT 1D satellite is presented, showing the excellent agreement between the theoretical and experimental results. 相似文献
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15.
Proposed is a novel miniaturisation method of a coaxial beam-rotating antenna (COBRA) lens horn for high power application. Generally, a miniaturised horn increases the phase error at the aperture because of large flare angle which causes gain decrease. However, since the proposed COBRA lens horn compensates phase error with a modified COBRA lens, radiation characteristics such as gain and radiation pattern of the miniaturised COBRA lens horn are similar to the conventional one while the length of the horn is reduced by more than 50%. 相似文献
16.
The effect of metallization thickness in striplines is investigated on the basis of the quasi-static and frequency-dependent hybrid-mode formulations. The formalism utilizes the aperture fields as source quantities and uses the extended version of the network analytical methods of electromagnetic fields. It is therefore applicable for the general structure, i.e., coupled thick strips with uniaxially anisotropic media. Numerical computations include comparisons with available data for the simpler cases to show the accuracy of the present method and the quasi-static and frequency-dependent hybrid-mode solution for single and coupled thick strips with anisotropic media 相似文献
17.
A. A. Kuraev A. K. Sinitsyn 《Journal of Communications Technology and Electronics》2006,51(4):373-379
The rigorous theory of excitation of an irregular electrodynamic system is used to formulate and solve the problem of determining the profile of a horn operating on symmetric E modes that provides a required mode structure at the output and an optimum directivity pattern. 相似文献
18.
设计了一种新型太赫兹(THz)超高斯波纹喇叭天线。它由正弦曲线部分和线性平行部分组成,可同时激励起HE11和HE12两种模式。该天线工作的中心频点为0.34 THz,带宽大于40 GHz。在本文设计中,高斯基模的能量耦合效率可提高到99.8%。同时具有-37 dB的旁瓣电平和-50 dB的交叉极化特性。仿真和实测结果也表明此天线的优良性能,可以看出仿真结果与实测结果非常吻合。 相似文献
19.
The hybrid-mode operation of deep-submicron LDD pMOSPETs has been investigated experimentally. Based on the experimental results, analytical models for the threshold voltage, the device currents, the transconductance, and the output conductance were derived. The various current components in this mode of operation were extracted and identified. The effects of independently biasing the source, drain, gate, and body potentials on the device currents and parameters were examined. The body-induced-barrier-lowering (BIBL) effect, which is one of the VSB effects and introduced for the first time, has been used to account for the changes in both the threshold voltage and the device currents caused by the forward source-body bias 相似文献
20.
The authors present a systematic process for the design of multimode quasi-integrated horn antennas, and provide a full range of practical antenna designs for millimeter- and submillimeter-wave applications. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is used in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate model. This results in a simple and efficient design process. The design procedure has been applied to the design of 20-, 23-, and 25-dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97%. The designed antennas have been tested and characterized using both full-wave analysis and 91/370-GHz measurements. The quasi-integrated horn antennas are also examined as feed elements for Cassegrain antenna systems and are proved to be comparable to the traditional machined corrugated horn feeds 相似文献