脊波导缝隙圆极化天线的设计*

设计了一种新型脊波导缝隙圆极化天线。在脊波导宽边开并联纵缝,从波导耦合电磁波至其上方的四脊波导圆极化器,实现圆极化辐射。采用脊波导不仅减小了单元尺寸,更改善了天线的带宽性能。重点研究了四脊波导圆极化器对相互垂直的两辐射场分量的影响,优化单元的轴比特性。在提取单元谐振电导的基础上,设计了工作在10GHz 的1×10 圆极化波导缝隙阵列。对天线实物测试得到中心频率处的增益为16.8dB,第一副瓣电平为 25dB,阻抗带宽约为8.5%,相对轴比带宽(AR臆3dB)约为3.2%。     

一种Ka频段高效率圆极化宽角扫描波导缝隙相控阵天线

该文提出一种新型小尺寸、低剖面、“f”字型波导缝隙圆极化器,高度仅1/6波长,宽度约2/5波长。基于该圆极化器,设计了一种高效率、低剖面、圆极化脊波导缝隙线阵天线。为满足空间应用中对轻质、高效率、圆极化、±60°宽角扫描相控阵天线的需求,采用该线阵天线作为阵元设计、仿真并实现了16阵元Ka频段脊波导缝隙相控阵天线。仿真和实测结果表明,该相控阵天线可实现1维±60°宽角扫描。在扫描角范围内,相控阵天线的轴比小于4.1 dB,增益下降小于4.3 dB。在0°扫描角工作时,天线的实测增益为35.9 dBi,辐射效率接近85%。     

一种Ka频段高效率圆极化宽角扫描波导缝隙相控阵天线

该文提出一种新型小尺寸、低剖面、"f"字型波导缝隙圆极化器,高度仅1/6波长,宽度约2/5波长.基于该圆极化器,设计了一种高效率、低剖面、圆极化脊波导缝隙线阵天线.为满足空间应用中对轻质、高效率、圆极化、±60°宽角扫描相控阵天线的需求,采用该线阵天线作为阵元设计、仿真并实现了16阵元Ka频段脊波导缝隙相控阵天线.仿真和实测结果表明,该相控阵天线可实现1维±60°宽角扫描.在扫描角范围内,相控阵天线的轴比小于4.1 dB,增益下降小于4.3 dB.在0°扫描角工作时,天线的实测增益为35.9 dBi,辐射效率接近85％.     

倒L形枝节加载宽带圆极化缝隙天线

设计了一种倒L形枝节加载宽带圆极化缝隙天线。天线为单层矩形结构,采用共面波导(CPW)馈电,通过在馈线上端加载倒L形枝节和在环形接地面上加载T 形枝节,实现了天线的宽阻抗带宽和宽轴比带宽特性。实测结果表明,S11 ￡-10 dB 的阻抗带宽达到115%(1.6-5.9 GHz),轴比￡3 dB 的圆极化带宽为48.3% (2.2-3.6 GHz)。该天线结构简单、易于制作,具有较好的应用前景。     

一种宽带宽波束圆极化微带天线的设计

文设计了一款宽带宽波束圆极化微带天线。 天线采用堆叠的双层圆贴片结构,结合四点顺序旋转馈电方式,实现了宽带圆极化辐射性能;在叠层圆贴片周边加载垂直接地金属柱环形阵,利用波束引向作用和等效零模谐振特性,在大带宽范围内实现了半功率波束宽度(HPBW)的有效展宽,并保证宽带宽波束内的圆极化辐射性能。 对天线进行了加工、测试。 实测结果表明,S11 小于-10 dB 的阻抗带宽( 4. 54 GHz ~ 11. 50 GHz)为 87%,覆盖了期望的应用工作频带6 GHz ~ 10 GHz;轴比小于3 dB 的带宽达到了33. 1%(6. 71 GHz~ 9. 36 GHz);HPBW 在6 GHz~ 8 GHz 范围内接近100°,在整个带宽内均超过 75°;除了 9. 5 GHz 以上频段,工作频带内的 6 dB 轴比波束宽度覆盖范围都接近 200°,表明天线在宽带和宽波束内具有良好的圆极化性能。     

新型宽带圆极化毫米波平面缝隙天线

研究了一种新型共面波导馈电的宽带圆极化毫米波平面缝隙天线.通过新型的短路微扰法实现了平面圆环形缝隙天线的单馈宽带圆极化,回波损耗(RL)≤-10dB时的实测阻抗带宽达到约20%,AR≤3时的实测轴比带宽约为21.2%,实测最大增益约为5.2dB.实测结果与ANSOFT HFSS软件仿真结果基本吻合,表明了设计的合理性.     

一种宽带四脊波导正交模极化耦合器

坐落于贵州天然喀斯特地形的500 米口径球面射电望远镜(FAST),其低噪声接收机系统需要高性能正交模极化耦合器,对此,提出了一种四脊波导形式宽带正交模极化耦合器快速有效的设计方法:首先分别设计四脊波导正交模极化耦合器的两个关键部分,然后进行整体优化,为了改善带内阻抗匹配性能可以在同轴输出端口的内探针引入阶梯匹配环。使用这种方法研制的FAST L 波段极化器工作带宽达到2 颐1,在整个带宽范围内极化器的反射系数小于-20 dB,极化耦合水平低于-43 dB,带内插入损耗优于0. 15 dB,仿真和实测结果有很好的一致性。提出的设计方法适用于各种频率范围的宽带四脊波导正交模极化耦合器的设计。     

一种W波段圆极化微带天线研究

研究了不同馈电形式的W波段圆极化微带天线阵列,并采用等幅同相馈电方式以及新型波导到微带过渡结构,完成了圆极化阵列天线的设计.由理论分析和仿真结果可知,通过选择合适的介质,以及利用单元间等幅同相馈电,既能有效减小W波段天线的损耗,又能实现圆极化的良好轴比特性.功分网络的合理排布,波导到微带过渡结构亦有利于减小天线损耗.对8×8阵列天线进行实测,S(1,1)小于-15dB的相对带宽为4.3%,轴比小于3dB的波瓣宽度为11°,中心频点94GHz时天线增益为20.6dB,与仿真结果基本吻合.     

高增益宽带圆极化微带天线阵研究

研究了S波段高增益宽带圆极化天线阵的设计方法,讨论了阵列间距与天线增益、E面方向图之间的关系,论述了微带天线阵馈电网络工程实现途径,并研制了S波段高增益宽带圆极化天线阵实验样机,并对天线阵实验样机的电特性进行了测量,测量结果表明,天线最大增益为15 dB时,天线阵的阻抗带宽达到了12.25%,圆极化轴比小于3 dB带宽为9.4%,测试数据充分说明了该天线阵具有尺寸小、高增益、宽频带、圆极化特性,从而验证了设计方法的有效性.     

圆极化微带贴片天线辐射和散射特性研究

提出了一种改进的宽带圆极化微带天线。该天线采用单端口、共面波导馈电。通过仿真优化,获得了32.7%的圆极化轴比带宽(AR<3dB),和47.6%的阻抗带宽(VSWR<2.0)。测量天线样机的阻抗带宽为44.4%,较好地吻合了仿真计算结果。最后,以设计天线为例,研究了圆极化微带贴片天线的辐射特性和散射特性,为圆极化天线雷达截面减缩技术打下了良好的理论和实验基础。     

A dual polarized aperture coupled circular patch antenna using a C-shaped coupling slot

The design and development of a dual linearly polarized aperture coupled circular microstrip patch antenna at C-band are presented. The antenna uses a novel configuration of symmetric and asymmetric coupling slots. Variations in isolation between orthogonal feedlines and antenna axial ratio with the position of coupling slots are studied and broadband isolation and axial ratio are achieved. The prototype antenna yields 7.6 dBi peak gain, 70/spl deg/ 3-dB beam width, 25 dB cross-polarization levels and an isolation better than 28 dB between the two ports. With an external quadrature hybrid coupler connected to the two orthogonal feedlines, the antenna yields 3-dB axial ratio bandwidth of more than 30% at 5.8 GHz.     

Broadband circularly polarised crosspatch- loaded square slot antenna

A new design of a circularly polarised square slot antenna loaded with a cross patch is presented. A cross patch inclined diagonally with respect to the square slot is placed at the centre of the square slot. By choosing proper dimensions of the cross patch, two orthogonal resonant modes with a 90deg phase difference for circular polarisation can be excited and feed the square slot antenna using a 50 Omega CPW with a protruded signal strip. 10 dB return loss bandwidth of 846 MHz (39.6%) and 3 dB axial ratio bandwidth of 240 MHz (12.4%) for the proposed antenna are achieved. Gain variation within the CP bandwidth is observed to be less than 1 dB     

机载圆锥对数螺旋天线及两种馈电方式的研究

论述了机载圆锥对数螺旋天线及其两种馈电方式的设计方法.利用FEKO软件对圆锥对数螺旋天线和两种平衡馈电方式进行了优化仿真分析.结果说明,该天线的电特性能够满足实际工程应用要求.在此基础上,研制了天线实物样机,并对该天线实物样机进行了测试.测试结果表明该天线在2.5～8GHz的工作频率范围内,方向图3dB波瓣宽度为100°左右,轴比小于3dB,驻波系数小于2.测试数据说明该天线的测试结果和仿真分析结果吻合良好,同时也说明该圆锥对数螺旋天线具有宽频带圆极化及宽频带宽波束特性,进而说明该设计方法是有效可行的,并可以推广应用.     

Constructing the phase converters consisting of arbitrary number oftranslucent surfaces

An effective analytical method of synthesis of an artificial anisotropic structure has been developed. At a design frequency, it ensures perfect match and a phase shift given. The structure may be formed by arbitrary number of inductive and capacitive grids. The method has been applied to constructing circular polarizers and twist polarizers. The geometrical parameters of the polarizers were found in the explicit form. Analytical criteria for an estimate of the bandwidth of the devices have been derived. Performance of the polarizers over a frequency band was studied. A circular polarizer has been proposed which consists of both a cascade of two inductive grids and a cascade of two capacitive grids. The polarizer can be used when very high axial ratio is needed. It ensures more than 10% bandwidth for 0.99 axial ratio. Measurements have been presented that prove adequacy of the mathematical model for real inductive and capacitive screens     

一种用于5G MIMO 系统的宽带高增益圆极化天线

为提升5G无线通信系统容量,设计了一款基于V 形缝隙耦合馈电的宽带高增益圆极化天线。该天线采用双层辐射贴片结构,拓展天线的阻抗带宽,并分别在辐射贴片和寄生贴片上刻蚀一对半径不等、位置正交的双圆形缝隙,有效改善了天线的圆极化特性。通过加载平板反射器提高天线的前后比,实现良好的定向辐射。实测结果表明,驻波比小于2的阻抗带宽为53.55% (2.27~3.93 GHz),在半功率波束宽度范围内轴比小于3 dB,轴比带宽为27.38%(2.9~3.82 GHz),在工作频带内实测的天线平均增益达到8.22 dBi。该天线适合作为5G多天线系统中的智能天线单元进行自适应波束赋形。     

基于Bragg光栅的超高消光比SOI波导偏振器设计

波导偏振器是片上集成相干光学系统中的关键器件之一,超高消光比、低损耗、紧凑型波导偏振器的设计一直是研究的热点。基于绝缘体上硅平台的倾斜Bragg光栅被用于实现超高消光比波导偏振器结构。利用一维光子晶体能带理论分别计算TE和TM模式光的能带结构分布,选择TE模式禁带与TM导带重叠带隙设计光栅,可实现TM模式低损传输,而TE模式被Bragg光栅高效反射,从而产生超高偏振消光比。3D FDTD仿真表明:16 μm倾斜Bragg光栅波导偏振器可在中心波长1550 nm附近70 nm的带宽内,实现大于37 dB的超高消光比,器件的损耗小于0.64 dB;进一步增加光栅周期数,当长度为25 μm时,消光比可提高至46 dB。Bragg光栅倾斜角与刻蚀宽度偏差仿真表明:设计的结构加工误差容限较大,同时该结构仅需一次曝光刻蚀,工艺流程简单。     

Low-Cost Broadband Circularly Polarized Printed Antennas and Array

This paper presents the design, simulation, and measurements of two low-cost broadband circularly polarized (CP) printed antennas: an element and an array at 2 GHz. To realize the broadband circularly polarized antenna element, a circular microstrip patch is electromagnetically coupled by crossed slots cut in the ground plane, which is fed by an L-shaped microstrip feed. Two orthogonal modes in the patch are excited by using the crossed slots, and a single L-shaped feed provides a 90deg phase shift between two orthogonal slots. The antenna element achieves a 9.6% bandwidth for an axial ratio (AR) below 3 dB and a voltage standing wave ratio (VSWR) below 1.5. To further improve the performance, a sequentially rotated feed network is designed for a 2 times 2 array. The axial ratio value of the array is below 3 dB within a 27.2% bandwidth, from 1.75 GHz to 2.3 GHz. The return loss is above 10 dB within a 41% bandwidth, from 1.62 GHz to 2.45 GHz. Details of the proposed antenna element and the array design are described, and both the simulation and the experimental results are presented and discussed.     

A wave polarization converter for circular polarization

A linearly polarized wave may be converted to a circularly polarized wave by means of a panel which provides90degdifference in transmission phase between two crossed linear components. This phase difference is obtained over a wide frequency band by means of thin sheets containing both inductive and capacitive shunt susceptance. Low reflection and near unity axial ratio may be obtained by means of three sheets which are spaced for least reflection. An experimental polarizer has been constructed using three photo-etched sheets and a dielectric honeycomb core. Over a 20 per cent band the axial ratio of the circular polarization is within 1.7 db and the insertion loss is within 0.5 db. Over a 46 per cent band the axial ratio is less than 2.0 db and the insertion loss is less than 1.0 db.