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为拓展工作带宽,以传统正反渐变槽天线为基础,利用基片集成波导馈电,该文提出了两种高增益、宽频带的正弦渐变槽天线。利用矩形波导3 dB定向耦合器和90移相器工作原理设计了半模基片集成波导单脉冲馈电网络,进而得到了对称型和非对称型正弦渐变槽单脉冲天线,带宽均超过了3.0 GHz,带内和波束最大增益在9.0 dBi左右,差波束零深在10.0 GHz处均低于-20 dB。其中,非对称型正弦渐变槽单脉冲天线具有更宽的工作频带和更平稳的天线增益,可以广泛应用于微波定向探测系统中。 相似文献
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An antipodal Vivaldi antenna (AVA) with band-notched characteristics is proposed in this paper for ultra-wideband (UWB) applications. For UWB systems, there will be some interference from the narrow band systems. The proposed antenna adopts resonant parallel strip (RPS) to reject an unwanted narrow band. It is easy to tune the RPS to eliminate the interference band. To validate this approach, a printed AVA with RPS is simulated and fabricated. From 2 to 9 GHz, the proposed antenna shows a good result with approximate 2:1 VSWR, an average gain of 6.5 dB, and stable radiation patterns except the notched band. At the center frequency of the notched band, the measured results show that the VSWR is more than 8:1, the realized gain is less than −10 dB and a messy radiation pattern is achieved. The simulated and measured results are in good agreement. 相似文献
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We present several algorithms for self-intersection detection, and possible elimination, in freeform planar curves and surfaces. Both local and global self-intersections are eliminated using a binormal-line criterion and a simple direct algebraic elimination procedure that enables the direct solution of the algebraic (self-)intersection constraints.All algorithms have been fully implemented and tested. Examples are presented for applications in self-intersection detection, self-intersection-free metamorphosis of curves, and proper trimming of self-intersections in offset curves. 相似文献
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提出了一种新颖的対拓Vivaldi天线。该天线的辐射耀斑用新的复合指数曲线修正。为改善天线的辐射特性(增益,波束偏离和交叉极化),提出了一个新的引向器,该引向器由两个混合椭圆金属贴片构成。测试结果表明该天线在1到40GHz频率范围内增益>0dBi, 并且在15到40G频段内天线的增益>12dBi。在3到40GHz频率范围内,E面的波束偏离小于3°,并且在15到40GHz不超过2°。 相似文献
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在被动毫米波 (PMMW) 成像焦平面阵列 (FPA) 馈源的天线中,直线渐变缝隙天线 (LTSA) 相对于传统的喇叭天线、介质棒天线具有其独特的优势。该文优化设计了一种新型的对跖直线渐变缝隙天线 (ALTSA),通过加载超材料结构使天线的增益得到了改善,天线采用基片集成波导 (SIW) 技术进行馈电。通过仿真与测试分析,该天线在较宽的频带内具有良好的阻抗特性、较低的副瓣电平及较高且平稳的增益,所设计的天线具有较小的口径宽度,在焦平面中易于组成较为密集的馈源阵列,以提高被动毫米波成像的空间分辨率。
相似文献8.
Changfei Yao Jinping Xu Mo Chen 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(3):243-249
A Ka-Band hybrid integrated single-ended mixer with low conversion loss is designed in this paper. In the proposed circuit
architecture, metallic via holes are implemented along the mounting edge of substrate embedded in the split-block of WG (waveguide)-finline-microstrip
transition. Simulated results show that the effect of high-order modes due to the mounting groove is effectively eliminated
and the transition loss is greatly improved. Meanwhile, a slow wave and bandstop filter at Ka band, which presents an equivalent
short circuit, is designed for the maximized utilization of idle frequency energy, RF and LO signal energy. In this way, the
conversion loss of the mixer can be further improved. The lowest measured conversion loss 3.52dB is obtained at 32.2 GHz;
the conversion loss is flat and less than 5.68dB over the frequency band from 29 to 34 GHz.
Supported in part by National Natural Science Foundation of China (NSFC) under Grants 60621002 and in part by NSFC under Grants
60471017. 相似文献
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Toshihiro Abe 《Computational statistics & data analysis》2011,55(12):3271-3282
Models for circular data displaying two diametrically opposed modes are considered. A general construction which can be used to generate such models, founded upon doubling the argument of a base symmetric unimodal distribution and cosine perturbation, is proposed. Fundamental properties of the resulting models are described, as are those of a particularly flexible family of distributions and three of its submodels. Parameter estimation via the method of moments and maximum likelihood is discussed, and a likelihood-ratio test for antipodal symmetry developed. The application of the proposed models and inferential methods is illustrated using two animal orientation data sets. 相似文献
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This paper proposes a stable gain and a compact Antipodal Vivaldi Antenna (AVA) for a 38 GHz band of 5G communication. A novel compact AVA is designed to provide constant gain, high front to back ratio (FBR), and very high efficiency. The performance of the proposed AVA is enhanced with the help of a dielectric lens (DL) and corrugations. A rectangular-shaped DL is incorporated in conventional AVA (CAVA) to enhance its gain up to 1 dBi and the bandwidth by 1.8 GHz. Next, the rectangular corrugations are implemented in CAVA with lens (CAVA-L) to further improve the gain and bandwidth. The proposed AVA with lens and corrugations (AVA-LC) gives a constant and high gain of 8.2 to 9 dBi. The designed AVA-LC operates from 34 to 45 GHz frequency which covers 38 GHz (37.5 to 43.5 GHz) band of 5G applications. Further, the presented AVA-LC mitigates the back lobe and sidelobe levels, resulting in FBR and efficiency improvement. The FBR is in the range of 12.2 to 22 dB, and efficiency is 99%, almost constant. The AVA-LC is fabricated on Roger’s RT/duroid 5880 substrate, and it is tested to verify the simulated results. The proposed compact AVA-LC with high gain, an improved FBR, excellent efficiency, and stable radiation patterns is suitable for the 38 GHz band of 5G devices. 相似文献
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