共查询到18条相似文献,搜索用时 171 毫秒
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前端设备由抛物面天线、低噪声下变频器(高频头)LNB、“功分”器、卫星接收机、邻频调制器、解调器、制转器和混合器组成。1 抛物面天线安装C波段抛物面天线一般由6~12瓣反射面组成,天线直径一般选(2.4~3.2)m天线,安装时必须按照厂方提供的编号顺序两两拼装,组成两个半圆形,将装好加强支架底盘与两个半圆抛物反射面装在一起。注意此时所有螺丝都不要拧紧,待把天线面装上后,整理各面平整,各瓣无间隙凹凸时再拧紧螺丝。在安装3根馈源支架时,支架可调长度的螺钉拧进的深度应一样,以保持馈源在中心线上。馈源和高频头的连接中,其矩形波… 相似文献
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在卫星星座跟踪、远距离微波能传输等需要构建大功率均匀场的领域,都需要具有平顶波束的高增
益反射面天线。受多模和混合模喇叭天线的启发,文中创新性地在反射面天线设计中引入了多模的理念。首先提
出了双模反射面的思路,即在标准抛物面天线的最大辐射方向上引入相位差为180°的反相模式场,由两种模式合成
平顶波束。然后,将双模的理念推广开来,总结出多模反射面天线的一般理论,即由反射面的不同区域激励多种模
式的信号,合成期望的赋形方向图。文中还详细介绍了多模反射面天线的多种结构形式、模态变化和实现方式,并
依此理论成功设计了具有平顶方向图的C 波段高增益反射面天线,为传统反射面天线的发展与应用提供了新的理
论与技术支持。 相似文献
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抛物反射面天线,在雷达及微波通信中是广泛应用的天线。近年来,由于卫星通信与卫星电视转播的发展,使它的应用日益广泛。抛物面天线由旋转对称的旋转抛物面(反射面)与馈源组成。由于反射面是固定的旋转抛物面,天线的性能在很大程度上取决于馈源的性能。所以,为了改善和提高抛物面天线的性能,近年来天线工作者把相当多的注意力都放在馈源的研究与改进上,要求馈源与反射面密切匹配。也就是说,作为反射面天线的馈源,要求它能在天线反射面的口面上形成一个适当的场分布。这种分布使得天线在某个频带内,在某一给定的旁瓣电平的前提下能得到最大的增益。这除了在设计天线时正确选择馈源的波束宽度与之相配外,还要求馈源的辐射方向图旋转对称、交叉极化激励得要低、旁瓣与后瓣电平要低,在 E 面与 H 面的相位中心要重合,再有馈源与其支架结构对天线的遮挡要小。 相似文献
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本文叙述了背射模螺旋与轴模螺旋的差别,推导了背射模螺旋天线远区幅射场,研究了以它为馈源的小型反射面天线的辐射特性,给出了工作在L和C波段抛物面天线的实际性能,天线效率达到并超过70%。 相似文献
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卫星接收设备主要可分这几部分。天线系统,含天线和馈源;连接部分,含高频电缆、接插件及电源连接;卫星电视接收机,含模拟及数字两种接收机以及彩色电视机等。 现在让我们了解一下卫星电视接收过程。 由电视卫星上的转发器天线送出电视载波信号,又称下行信号,它有C和Ku波段之分,从特性看,有模拟和数字压缩方式。该信号被地面站天线所接收,目前接收天线常用的是前(正)馈抛物面天线,它用于 C/Ku波段;偏馈天线(单偏馈抛物面天线),它可用在C波段,但更多用于Ku波段。下行信号会聚在抛物面天线反射面的焦点(F)上,… 相似文献
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Microstrip-fed quasi-Yagi antenna with broadband characteristics 总被引:1,自引:0,他引:1
A compact and uniplanar antenna with broadband characteristics is presented. The novel Yagi-like printed dipole array antenna is fed by a microstrip-to-coplanar strip transition, and uses the truncated microstrip ground plane as its reflecting element. An X-band prototype measures a bandwidth of 17%. With 6.5 dB gain, 18 dB front-to-back ratio, and lower than -15 dB cross-polarisation level at 10 GHz 相似文献
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《Antennas and Propagation, IEEE Transactions on》2009,57(5):1360-1366
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Kin-Lu Wong Chih-Hua Chang 《Antennas and Propagation, IEEE Transactions on》2005,53(11):3496-3499
A novel wireless local-area network (WLAN) chip antenna suitable to be mounted above the system ground plane of a mobile device is presented. The antenna in the study is easily fabricated from folding a single metal plate onto a foam base, and mainly comprises a short-circuited radiating strip and an antenna ground. The antenna ground occupies the bottom surface and two adjacent side surfaces of the foam base. When the antenna is mounted at the corner of the system ground plane, this antenna ground structure is expected to effectively reduce the antenna's possible fringing electromagnetic fields inside the mobile device. In this case, when the associated element such as the radio-frequency shielding metal case is placed under the proposed antenna, small or negligible variations in the antenna performance are obtained. Design considerations of the proposed antenna for WLAN operation in the 2.4 GHz band are described, and results of the constructed prototypes are presented. 相似文献
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Compact triple band antenna for WLAN/ WiMAX applications 总被引:3,自引:0,他引:3
A low profile printed antenna with triple band operation is presented for simultaneous use in wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna consists of a rectangular radiating element fed asymmetrically by a 50 Omega microstrip line and a shaped trapezoidal ground plane. Rectangular horizontal strips are attached to the radiation element to form different current paths which make the antenna resonate in WLAN and WiMAX frequency bands. The antenna operates in dipole configuration outlining overall dimensions of 38 times 30 times 0.8 mm3. 相似文献
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A planar artificial magnetic conductor (AMC) ground plane is proposed as a means to reduce the profile of a highly directive resonant cavity antenna. The structure is formed by a printed microstrip patch antenna and a superimposed partially reflective surface. The antenna profile is reduced to approximately half by virtue of employing the AMC ground plane. A ray theory model is used to qualitatively describe the functioning of the antenna and theoretically predict the existence of quarter wavelength resonant cavities. 相似文献
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《Advanced Packaging, IEEE Transactions on》2009,32(4):797-808
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CPW-fed crescent patch antenna for UWB applications 总被引:1,自引:0,他引:1
A novel printed antenna for ultra-wideband (UWB) applications is presented. The antenna consists of an open annulus strip as a ground plane and an open crescent patch in the inner space of the annulus as a radiating element. The antenna is fed by a coplanar waveguide with a central strip connected to the crescent patch. The antenna has a compact structure, and the total size is 33 times 30 times 1.57 mm. A relative impedance bandwidth of 129% is achieved, which covers 3-14 GHz. 相似文献