Printed ring slot antenna for circular polarization

A new design of a microstrip-line-fed circularly polarized printed ring slot antenna is proposed. Circular polarization (CP) radiation of the proposed design is achieved by introducing proper asymmetry in the ring slot structure and feeding the ring slot using a microstrip line at 45° from the introduced asymmetry. The asymmetry introduced in the proposed design is a meandered-slot section and the proposed CP design can be applied to printed square and annular ring slot antennas. Prototypes of the proposed design have been implemented. Experimental results show that good CP radiation performances are obtained and the 3 dB axial-ratio CP bandwidths obtained for the square and annular ring slot antennas are about 4.3% and 3.5%, respectively     

Electric tripole antenna for circular polarization

The feasibility of using the tripole antenna for circular polarization was experimentally investigated. Measured impedance and radiation patterns were in agreement with the predictions from the infinitesimal tripole model. For simultaneous operation in both senses of circular polarization the tripole antenna must be fed by a special separator network, preferably of the nonreciprocal type.     

Rectangular microstrip antenna for circular polarization

Richmond's reaction integral equation method is used to design a rectangular microstrip patch to produce a circular polarization. A rectangular patch with the aspect ratioa = W_{x}/W_{y}, in the range 1.015- 1.02 and corner fed by a microstrip line, produces circular polarization. For substrate with thicknessd = 0.16cm,a = 1.017the nearly square patch gives maximum bandwidth.     

新型小尺寸双陷波超宽带天线设计

提出了一种基于槽天线的小型化、高隔离度的超宽带(Ultra Wideband, UWB)多入多出(Multiple-Input Multiple-Output, MIMO)天线.该MIMO天线由两个槽天线单元构成, 为了增加天线阻抗带宽, 每个槽天线单元由末端带有圆形贴片的微带线和末端为圆形的槽线两部分耦合馈电.采用在地板上开槽和方向图分集方法, 减少地板表面波和空中电磁波影响, 达到提高天线隔离度的目的.数值仿真和实验结果表明:该天线在3.1~11 GHz频段内满足端口反射系数|S₁₁| < -10 dB, 隔离度|S₁₂|在7~11 GHz频段内小于-25 dB, 在3.1~7 GHz频段内小于-16 dB, 并根据仿真和测试S参数计算了包络相关系数.     

Printed circular disc monopole antenna for ultra-wideband applications

A novel and simple design of a printed circular disc monopole antenna for ultra-wideband applications is presented. The parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.     

Printed antenna and array with circular polarisation

A new type of printed antenna element, as well as an array of elements with circular polarisation, is shown. The antenna has a much wider bandwidth than known circularly polarised printed antennas, mostly microstrip patches. The method of design and realisation with experimental results is shown     

A wider band microstrip antenna for circular polarization

Circular polarization is achieved by separating two degenerate orthogonal modes in an annular ring patch antenna, by using an ear at the outer periphery. The analysis of such a structure is performed by using the generalized transmission line model. It is found theoretically that this structure can be used to generate circular polarization over a wider frequency range than other structures. An annular ring is designed and its performance is evaluated. Good agreement between the theory and the experiment is obtained. It is also found that the axial ratio bandwidth is higher for the TM₁₂ mode than the TM₃₂ mode of operation in an annular ring antenna     

Cross-slot-coupled microstrip antenna and dielectric resonatorantenna for circular polarization

Circular polarization (CP) design of microstrip antennas and dielectric resonator (DR) antennas through a cross slot of unequal slot lengths in the ground plane of a microstrip line is demonstrated. The proposed CP design is achieved by choosing a suitable size of the coupling cross slot, which results in the excitation of two near-degenerate orthogonal modes of near-equal amplitudes and 90° phase difference. This CP design can be applied to both configurations of microstrip antennas and DR antennas and has the advantages of easy fine-tuning and less sensitivity to the manufacturing tolerances, as compared to their respective conventional single-feed CP designs. For the proposed design applied to a low-profile circular disk DR antenna of very high permittivity studied here, a large CP bandwidth, determined from 3-dB axial ratio, as high as 3.91% is also obtained. Details of the proposed antenna designs are described, and experimental results of the CP performance are presented and discussed     

一种用于卫星定位系统的宽波束圆极化天线

在卫星通信、定位设备中,为了迅速完成定位和通信功能,一般要求天线具有较大的波瓣宽度和较好的低仰角增益.研究设计了一种具有良好低仰角增益的宽波束圆极化四臂螺旋天线,该天线在上半空间的增益分布十分均匀,10°仰角的增益相对峰值增益下降不超过 3dB.为了改善天线的轴比性能,提出了一种4臂等幅、相位依次相差 90°馈电的天线方案,仿真结果表明,这种天线的增益特性和轴比特性都得到了较大的改善.     

The design of a squarer-ring slot antenna for circular polarization

A new design of a circularly polarized square-ring slot antenna is proposed. The circular polarization is achieved by a series microstrip-line-feed configuration coupling to two orthogonal sides of the square-ring slot. A parametric study is conducted using a commercial simulation software based on the method of moments, and the design procedure is established. The required ground-plane size of the proposed design for a given frequency is also indicated. Three antenna prototypes respectively operated at distinct frequency bands are constructed and measured for providing the simulation validation. Experimental results show that the proposed antenna has good circularly polarized radiations and the 3 dB axial-ratio bandwidth is more than 6%.     

新型强耦合宽带双圆极化阵列天线

空间飞行器由于受到动力和负载的限制, 需要尽可能使搭载的天线轻质小型化.文中提出了一种新型强耦合双圆极化轻质天线.天线单元采用H型缝隙耦合和增加寄生贴片方法, 提高了天线带宽.同时, 通过在辐射贴片、寄生贴片上开圆形槽, 以及金属反射板栅格化的处理, 明显地减轻了天线的质量.采用这种新型天线单元, 设计了8单元的宽带双圆极化阵列天线.仿真结果表明:该阵列天线的中心频率为433 MHz, 左旋和右旋圆极化的相对轴比(Axial Ratio, AR)带宽(AR < 3 dB)分别达到了24.4%和23.2%, 有效实现了小型轻质化宽频带双圆极化阵列天线.     

小型宽波束圆极化天线及馈电网络

提出一种新型的小型宽波束圆极化天线及馈电网络。天线由四个独立辐射单元顺次旋转90°组合而成,辐射单元采用平面印刷电路工艺加工、使用容性加载及短路点调配方式实现小型化;使用变形的分支线定向耦合器与移相电路组合,实现具有功率分配与正交移相功能的馈电网络。经理论分析、软件仿真及实测表明:天线高度小于0.12λ,3 dB波束宽度大于120°,6 dB轴比波束宽度大于180°,辐射特性在15%相对带宽内稳定;天线的驻波比(VSWR)小于2.0的相对带宽为16%。该小型宽波束圆极化天线采用印刷电路工艺制作,结构紧凑,加工成本低、精度高,易于与微波电路集成,其结构也适用于S波段以上更高频段。     

一种圆极化可重构微带天线的设计

对圆弧寄生单元微带天线进行了理论分析,设计了一种圆极化可重构的圆形微带天线。该天线通过电控开关控制圆弧寄生单元的状态,从而实现左、右旋圆极化的转换。并利用仿真软件HFSS13.0对天线的特性进行了仿真验证。结果表明,在天线回波损耗S11<–10 dB时,该天线在频段为2.38~2.51 GHz,3 dB轴比带宽为30 MHz,且最大辐射方向处正交极化差达20 dB以上。天线的整体辐射性能良好,且结构简单易于实现,很容易在低频段匹配到50,能够满足WLAN在2.4 GHz频段的要求。     

高增益低副瓣X波段宽带圆极化Vivaldi天线阵设计

设计了一种新型的覆盖X波段的宽带圆极化2×2天线阵,具有高增益、低副瓣和良好的圆极化性能.该阵列以Vivaldi天线为基本单元,采用旋转对称的十字形结构,四端口等幅馈电且相位依次为0°,90°,180°和270°.此天线阵在整个X波段内阻抗匹配良好,轴比均低于3dB.采用矩形栅栏和底部扼流环结构将天线地板上的表面电流集中在槽线附近并降低后向辐射,从而获得低副瓣和高增益.频段内的峰值增益为10.7 dB,前后比大于20 dB.两个主平面的方向图对称性良好且基本重合.各天线单元间的低耦合使得天线阵的交叉极化很低.实物测试结果与仿真结果基本吻合.     

一种弹载宽带圆极化天线阵设计

本文设计了一种工作于X波段的弹载宽带圆极化四元阵.该阵列天线以印刷八木天线为基本单元,围绕导弹均匀布置,组成旋转对称的十字型结构.4个馈电端口的相对相位依次为0°、90°、180°和270°.利用镜像原理,使得单元天线尺寸减小了一半,实现了小型化,便于与载体共形.测试表明,该天线阵在整个X波段内回波损耗小于-10 dB,极化轴比基本小于3 dB,主辐射方向指向导弹正前方,平均增益为4.5 dB,满足设计要求,这与仿真结果较为一致.     

利用线极化天线快速测量圆极化天线轴比的方法

针对轴比测试需要连续旋转线极化天线极化轴,在高频段旋转关节难以消除高速旋转带来的电缆抖动所引起的幅度和相位不一致性,提出了一种快速、精确测量圆极化天线轴比的测试方法。基于椭圆极化波的正交分解理论,该方法利用线极化天线对待测圆极化天线进行两组正交的线极化幅度测量,通过计算得到圆极化天线的轴比等极化椭圆参数的信息。在此基础上又提出了只用三个线极化分量测量圆极化天线轴比的方法。通过在微波暗室中对圆极化天线进行多次测试,验证了该方法的有效性。该方法提高了圆极化天线的测试效率,降低了测试难度,对于工程应用有重要的应用价值。     

三频双圆极化北斗天线的设计

设计了一款新型的小型化多频段圆极化北斗天线。天线采用双层层叠结构设计,上层天线采用矩形贴片切角开缝的方法,实现北斗系统L频段的左圆极化;下层天线利用复合左右手传输线结构进行设计,通过在矩形贴片中间位置加入非对称十字和直角折线槽结构,同时在四角位置加入90o折线结构和金属过孔,实现北斗系统B1频段、S频段以及GPS L1频段的右圆极化。天线尺寸为39 mm×39 mm×6.8 mm。仿真结果表明该天线各项指标均满足北斗系统对天线性能的要求。