共查询到20条相似文献,搜索用时 132 毫秒
1.
2.
将射频开关和Koch分形振子天线相结合,设计了一种可工作在多个频段的射频开关加载的Koch振子天线。通过控制射频开关的通断,可使所设计的天线工作在几个不同的频段。所设计的Koch振子天线与普通振子天线相比,其长度有较大幅度的减小。HFSS软件仿真表明所设计的天线在几个不同的频段都具有良好的性能。 相似文献
3.
4.
5.
文中提出了一款新的蝶形双偶极子宽带印刷端射天线。在该天线设计中,引入阶梯槽线结构来改善天线带宽上的阻抗匹配,拓宽天线的带宽;在地板反射器和双偶极子驱动器上加载蝶形枝节来加长天线的电流流径,实现天线尺寸减小和带宽提高;在不改变天线尺寸的前提下,在引向器上下两边加载寄生贴片,扩大天线辐射口径,进一步提高天线的带宽和增益。所设计的天线被加工成实物并对其进行了测试,结果显示该天线在反射系数低于-10 dB情况下的频率范围为1.59 GHz~3.96 GHz,在相应带宽上,天线的增益为5.84 dBi~8.5 dBi。 相似文献
6.
讨论了共面波导(CPW)馈电蝶形开口振子缝隙天线。在缝隙振子天线两端加入蝶形开口结构,形成振子蝶形组合结构天线。使用有限元仿真软件(Ansoft HFSS)分析了设计的天线,结果表明组合结构天线具有振子天线与蝶形天线的优点:蝶形天线的宽带特性与振子天线的高增益特性,整个天线的性能得到提高。使用了两种馈电方式:感性耦合和容性耦合,感性耦合时组合天线的带宽特性较好,从振子天线5.9%提高到10.32%;容性耦合时增益特性较好,从振子天线的3.19dB提高至6.27dB。分析了衬底厚度对天线的影响,衬底厚度的增加使谐振频率降低,但对天线带宽的影响不大。 相似文献
7.
采用遗传算法和时城有限差分算法(FDTD),结合并行计算技术成功地构建了一套天线自动设计软件系统:"天基"天线自动设计系统.运用该天线自动设计软件系统,对一种采用泪滴状偶极振子和平面套筒结构的微带天线进行了超宽带和高端射增益的自动设计.根据设计结果制作了实际天线并进行了测试,测试结果表明该天线具有良好的超宽带性能,S11<-10 dB的频带超过了2.5倍频程(1.3~3.4 GHz),在此工作频带中,天线辐射为端射,最大端射增益达到了9.2 dBi. 相似文献
8.
9.
通过对同相馈电十字振子圆极化天线的分析,提出了用振子等效长度缩短模型来定性,分析其实现圆极化的原理.同时利用时域有限差分法对十字振子天线进行仿真.并在2个波长长度范围内找到了实现圆极化的振子尺寸,在满足一定轴比带宽条件下,在垂直于十字振子平面通过十字振子中心的轴线上圆极化轴比可以达到1.166 8.分析了当大线尺寸改变时,圆极化特性的变化规律.为同相馈电十字振子圆极化天线的设计提供了参考. 相似文献
10.
11.
Polarization of a simple turnstile antenna situated close to the human body, for potential WBAN applications at 2.45 GHz band, is studied in detail by the use of electromagnetic simulator WIPL-D Pro. Circular polarization of the antenna (when isolated) is provided by adjusting the dipole impedances. Full-size, 3-dimensional simplified homogeneous model of a human body is applied. Polarization of both far and near field is studied, with various positions of the antenna and with/without metallic reflector. In the far field significant degradation of the circular polarization, due to the vicinity of the body, was observed. In the near field, at points close to the surface of the torso, polarization (of vector E) was found to significantly deviate from circular. Obtained results can be useful in designing on-body sensor networks in which circularly polarized antennas are applied, for both far field communication between sensor nodes and the gateway and near field communication between sensors. 相似文献
12.
An antenna system is described for a spin-stabilized satellite with its axis normal to the orbital plane. Three antennas in a compact lightweight package comprise the antenna system: a switched-beamX -band transmitting antenna, an omnidirectionalX -band receiving antenna and an omnidirectional VHF telemetry antenna. The first is a cluster of eight circularly polarized horns pointed radially outward every 45 degrees about the spin axis. An eight-throw solid-state waveguide switch turns on that horn currently pointing most nearly to earth. This is accomplished by providing the switch with electrical signals from a logic circuit operating on information from earth sensors. The second antenna is a circularly polarized biconical horn located above the cluster of transmitting horns. Its sense of polarization is opposite that of the transmitting antenna, and a filter in the transmission line to the receiver insures the required isolation. The third antenna is obtained by feeding across the gap between the twoX -band antennas and exciting the external surfaces to radiate in a linearly polarized mode. Total weight of the three-antenna package is less than4frac{1}{2} pounds; it occupies a volume less than 10 inches square by 8 inches high above the top panel of the satellite. 相似文献
13.
现有的线极化天线单元组成的圆形天线阵要激发涡旋电磁波,需对天线阵进行等相位差馈电,馈电网络结构较复杂。文中首先从理论上探讨利用圆极化天线单元组成的圆形天线阵产生涡旋电磁波的可能性,基于圆极化波传播特性,通过旋转圆极化天线单元而使相邻天线单元的远区辐射场产生相位差,导出圆形天线阵远场区的电磁辐射公式,论证圆极化的圆形天线阵在同相位馈电时能产生涡旋电磁波束。进而,以8 个天线单元构成的圆形天线阵为例进行仿真验证。结果表明,通过合理的天线单元角度分布替代移相器模块功能,只需使用相同相位的馈电端口就能产生l =0,±1,±2,±3 七种模式的轨道角动量,这种新型轨道角动量激发技术有效提升了馈电网络设计的灵活性。 相似文献
14.
波束前倾结构后置天线(Forward Tilted Beam and Back-placed Antenna, FTBBA)在高超声速小型飞行器领域有广泛应用。文中采用水平磁+电壁构成端射元,利用电与磁的二重性原理和Yagi天线理论,构建C波段波束前倾结构后置微带八木天线以实现端射。同时,利用栅格结构人工电磁材料(Artificial Electromagnetic Structures, AEMS)抑制表面波,减小杂散电磁波对端射方向图和极化纯度的影响。此外,围绕高超声速小型飞行器天线的共形需求,将两组FTBBA共形于典型的高超声速飞行器表面以实现双极化端射。该天线能够在5.2~5.9 GHz实现VSWR<2 (相对带宽为12.6%),增益>11 dBi,主瓣波束宽度约20×32°。该天线突破端射波束控制技术,解决了常规技术手段难以克服的高速飞行器结构后置和波束前倾相互制约等技术难题。 相似文献
15.
16.
17.
18.
19.
This paper describes a combined panel antenna with an aperture of about eight wavelengths The combined antenna consists of a zigzag antenna and two collinear arrays. This antenna can be used to radiate vertically polarized, horizontally polarized waves or both, When properly phased it can be used to transmit or receive circularly polarized waves, 相似文献
20.
为了拓展倾斜波束圆极化天线(Circularly Polarized Antenna with Tilted Beam,CPA-TB)的带宽,在分析了该天线结构及其特征的基础上,提出了一种花纹式螺旋臂(Flower-Spiral,FS)协同互补开口谐振环(complementary split ring resontor,CSRR)的CSRR-FS结构.该结构通过FS增加了天线表面电流路径,实现了天线驻波比(voltage standing wave ratio,VSWR)的拓展;利用CSRR改变了低频点反射板的电流分布,实现反射板小型化的同时,减小了天线的交叉极化分量,增强了天线的辐射性能,拓展了天线的轴比带宽.仿真和实测结果表明:与普通的平面反射板相比,在保证圆极化、波束倾角30°的条件下,基于CSRR-FS结构的CPA-TB相对带宽为24%(5.5-7GHz),天线工作带宽拓展了1.8倍.CSRR-FS结构的提出为CPA-TB带宽的拓展提供了新的途径. 相似文献