An Experimental Study of the Printed-Circuit Elliptic Dipole Antenna with 1.5-16 GHz Bandwidth

Printed-circuit board (PCB) elliptic antennas with useful bandwidth exceeding 10:1 ratio are suitable for wideband radar, wireless ultra wideband (UWB) and other wireless communication applications. We present wideband PCB elliptic dipole antennas which are capable of achieving the bandwidth requirements for all the applications. A set of elliptic dipole antennas with varying eccentricities have been fabricated for demonstration. We find one specific size (specific eccentricity) dipole that can yield an impressive 1.5-16 bandwidth exceeding the currently available. A couple of elliptic dipole antennas suitable for UWB application have been presented. We have measured swept frequency response, impedance and radiation patterns of all dipoles. An empirical formula is given for calculating the starting resonant frequency within the operating band. The calculated values are found in good agreement with measured results.

Geometry Aspects and Experimental Results of a Printed Dipole Antenna

Detail experimental measurements of a 2.4 GHz printed dipole antenna for wireless communication systems is presented and discussed. A group of printed dipoles with integrated balun have been designed and constructed on a dielectric substrate. This paper is based on modifications of the known printed dipole architecture. The corresponding printed dipole antennas have differences on their forms that are provided by two essential geometry parameters. The first parameter l is related to the bend on microstrip line that feeds the dipole and the second w corresponds to the form of the dipole’s gap. The impact of these parameters on reflection coefficient and radiation pattern of antenna has been investigated. The corresponding measured results indicate that the return loss and radiation pattern of a printed dipole antenna are independent of the w parameter. Instead, variations in the value of the l parameter in the dipole’s structure affect the form of the corresponding return loss. These observations are very important and provide interesting considerations on affecting design and construction of antenna elements at frequency range of 2.4 GHz.

Design of Printed Dipole Array for Omnidirectional Radiation Pattern

In this paper, we describe 2 kinds of printed dipole arrays and compare the performances of these arrays in term of reflexion coefficient, radiation pattern and dimensions. It is interesting to design array in order to obtain better performances in term of omnidirectional radiation pattern in comparison with single element. We choose this elementary source in order to obtain compact array with good performances. These antenna arrays are designed to have omnidirectional radiation pattern with horizontal polarization. We present an application dedicated to compact base station in the last section.

Measurements of Balun and Gap Effects in a Dipole Antenna

In the present paper, design and analysis of a 2.4 GHz printed dipole antenna for wireless communication applications are presented. Measurements on return loss and radiation pattern of this antenna configuration are included in this investigation. The printed dipole is combined with the feeding structure of a microstrip via-hole balun and is fabricated on an FR-4 printed-circuit-board substrate. Two inevitable discontinuities are introduced by this antenna architecture in the form of right-angle bends in the microstrip feed line and in the dipole’s gap, respectively. The impact of mitering these bends in the reflection coefficient, resonance bandwidth and radiation pattern of antenna has been investigated by means of simulation and experiment.

A Compact Wideband Dual-Polarized Printed Antenna with Coaxial Feeds for TD-SCDMA Application

In this article, a low-profile wideband dual-polarized planar printed dipole antenna, fed by coaxial lines, is investigated for the TD-SCDMA operation. The antenna is composed of two printed dipoles, two pairs of feeding coaxial lines and a ground. The single-polarized planar printed rectangular dipole and petal dipole, with the similar configuration, are first studied, exhibiting the potential wideband operation. Two petal dipoles are then cross-arranged to design a dual-polarized planar printed antenna, giving a lower profile and a better bandwidth covering the Chinese TD-SCDMA band (1880-2400 MHz). The dual-polarized antenna is simply excited by two pairs of coaxial feeds. Simulated and measured results show that the antenna achieves a common impedance bandwidth of 42% at both ports, good isolation of more than 25 dB, stable radiation patterns and the gain of about 7 dBi over the operating bandwidth.

L波段全向天线研究与设计

在实际应用中,有时需要全向天线在水平面以上覆盖较广的空域,针对这一需求,文章提出了两种工作在L频段的波束上翘的全向天线。其中一种为使用同轴转平行双线结构进行馈电的串联印刷偶极子天线,且加入反射板保证波束上翘,实测结果表明该天线在工作频段内,电压驻波比(voltage stanting wave ratio,VSWR)小于1.5,水平面增益大于2dBi,俯仰角0°~70°(定义水平方向为0°)增益大于-7dBi,不圆度小于2dB。另一种为双锥天线,使用上下锥体不对称结构保证波束上翘,同时引入固定套环保证天线的稳定性。实测结果表明该天线在工作频段内,VSWR小于2,俯仰角0°~20°增益大于1dBi,俯仰角0°~70°增益大于-7dBi,不圆度小于2.5dB。该天线结构稳定,性能优良,可应用于车载通信或其他通信场景中。

一种宽频带复合天线设计

针对多系统载体天线数量多的问题,提出了一种基于印刷振子结构的宽频带共口径复合天线设计方法;通过两种不同形式的印刷偶极子进行共口径设计:采用平面印刷偶极子结构完成宽带高增益线极化天线,通过宽带定向耦合器实现了天线和差方向图辐射;采用十字印刷偶极子实现低增益天线的圆极化辐射;两种天线单元印刷在同一微波介质上,通过优化天线单元布局,相对位置关系和增加金属隔离环等措施,降低天线之间的相互影响,实现共口径复合天线性能满足工程应用要求;加工了天线样机,测试结果表明线极化天线在工作频带1.2~1.8 GHz范围内和差通道电压驻波比小于1.8,和通道增益大于13.5 dBi,方位差波束零值深度小于-25 dB,圆极化天线在工作频带1.2~1.8 GHz范围内电压驻波比小于1.6,增益大于6.5 dBi,轴比小于2.5 dB,与计算结果基本一致;复合天线可以满足多种无线通信系统的需求,减少了天线数量,有效节省载体平台空间,同时具有结构简单紧凑、剖面低、易于工程实现等特点,具有广阔的应用前景。

双频MIMO印刷偶极子天线设计

文章设计了一种具有双频工作特性的偶极子多入多出(Multiple Input Multiple Output, MIMO)天线,通过在接地板上开矩形缝隙并添加音叉型寄生微带枝节,达到了天线端口去耦合的目的,隔离度显著改善。偶极子天线单元由2个矩形开口环构成,2个环形谐振器的尺寸不同。天线实现了双频工作特性。在端口反射系数不高于-10 dB的情况下,该MIMO天线在1.63~2.01 GHz和5.61~7.02 GHz 2个频段内均实现了超过20 dB的隔离度。

一种宽带双极化印刷振子天线的设计

双极化印刷振子具有重量轻、体积小、成本低、便于排阵等优点,能发射或接收两个正交极化的电磁波,有利于频率复用或者收发同时工作。对双极化印刷振子进行了理论与实验研究。对用微带线巴伦进行耦合馈电的印刷振子的宽带特性进行了分析,并以单极化印刷振子的结构为基础,设计了一种双线极化印刷振子。最后对设计出的天线进行了实际测量,测量结果要好于仿真结果,说明该方法是正确可行的。

基于RFID应用的小型化印刷偶极子天线设计

为了研究满足工程需要的射频识别(RFID)标签天线,以2.45 GHz工作频段为例,给出了印刷偶极子标签天线及其小型化设计.所设计的2.45 GHz印刷偶极子标签天线的性能指标为:在驻波比小于1.5时,工作带宽约为450 MHz;天线增益为1.4 dB;天线尺寸大小为37 mm×45.8 mm.小型化后的天线尺寸缩小为31.8 mm×28.5 mm,面积减小了约47%,在驻波比小于1.5时,天线带宽约为220 MHz,天线增益为1.2 dB.此外,给出了小型化天线的实测结果,并且与理论结果进行了比较,结果吻合良好.

电磁带隙结构在天线雷达散射截面减缩中的应用

提出了一种使用电磁带隙结构来减小微带印刷对称阵子天线雷达散射截面的方法。该方法利用电磁带隙结构的带阻特性,使其能作为天线的地板,在带外(非谐振)时,电磁带隙结构对入射电磁波起滤波作用。仿真和实验的结果表明,电磁带隙结构能保证天线在带内辐射不受影响的同时,还大幅度地降低了天线带外的雷达散射截面。

一种方向图可重构印刷振子天线的设计

为了在同一副天线上实现定向和全向方向图,提出了一种方向图可重构印刷振子天线。通过控制开关的状态,天线实现单极子和带反射器的偶极子两种工作方式,分别实现全向和定向方向图。用Ansoft HFSS软件对天线尺寸进行了分析和优化。根据仿真结果对于所提出的天线进行了制作和测试,并给出了测试结果。测试结果表明:开关断开时,天线带宽为2.09～2.44GHz;开关闭合时,天线带宽为2.64～2.94GHz。

一种宽带UHF印刷偶极子天线的设计

设计制作了一种宽带UHF印刷偶极子天线。为了使天线在UHF的低频段获得宽带特性,采用了改进的Marchand巴伦馈电。该巴伦在传统的结构上,通过在接地板上开槽以改变耦合微带线与接地板之间的电容值,从而调整巴伦的奇偶模阻抗,以提高偶模阻抗与奇模阻抗的比值,实现带宽的拓展。仿真表明天线在530～790MHz范围内,回波损耗低于-10dB,相对带宽可达40%。加工制作了天线,实测结果与仿真数据吻合良好。这类天线在微波低频段具有特别的实用意义。

1.8GHz微带平衡巴伦馈电印刷偶极子天线

为实现天线的小型化,借助ADS2009电磁仿真软件,设计了一种1.8 GHz微带平衡巴伦馈电印刷偶极子天线。样机测试结果显示,该天线相对带宽为15.54%,增益为2.16 dB,输入阻抗为49.37+j1.605Ω,3 dB波瓣宽度为78.8°。实测特性阻抗、回波损耗特性、E面水平极化方向及H面垂直极化方向等电磁辐射性能与仿真结果基本相符。该天线可独立使用,或作为大型天线阵的辐射元。

一种波束赋形相控阵天线的分析与设计

设计了一种水平面赋形、俯仰面扫描的一维相控阵天线,天线单元采用印刷振子.为了获得低副瓣,馈电电流采用泰勒分布.为了满足0.2°扫描步进指标要求,采用虚位技术,通过4位移相器实现9位移相器功能,简化了设备,降低了成本.测试表明:在±15°扫描范围内,半功率波束宽度小于2.3°,增益大于25 dB,副瓣低于-25 dB,水平赋形方向图3 dB波束宽度33°,满足设计指标要求.

一种宽频带低交叉极化伞形印刷振子阵列天线

为了增加天线带宽及降低交叉极化,采用中心balun馈电双层伞形印刷振子天线结构,设计了一种新型宽带阵列天线.仿真表明,天线单元相对阻抗带宽(驻波比小于等于2)为38.8%,交叉极化电平小于-45 dB,前后比优于16.4 dB.阵列天线带宽达到39.4%,H面交叉极化电平小于-48 dB,增益达到16.2 dB.

印制电路板电磁辐射等效偶极子建模与预测

提出了一种计算由印刷电路板产生的电磁辐射的新方法。这种方法是从近场扫描推导出的等效偶极子模型,建立了一系列可以产生相同辐射场的无穷小偶极子来代替PCB板。等效偶极子的参数直接由被测近场磁场决定,在封闭环境下仿真,等效的方法被推广应用到电介质平面偶极子模型,通过等效PCB基本物理特征来解决在PCB板和外壳之间的相互作用。通过用数学法求解等效模型来预测电磁辐射,极大的减少了仿真时间,提高了仿真效率。最后,以一块印制电路板为对象,通过对其进行电磁辐射仿真与试验测试,证明了利用本文方法建模与预测的正确性和高效性。

一种915MHz印刷偶极子标签天线的分析与设计

射频识别技术由于具有体积小、容量大等优良性能而被广泛应用于很多领域。针对反射调制式RFID系统,介绍了一种基于ISO/IEC18000-6标准应用的RFID印刷偶极子标签天线及其优化设计方案。首先进行了915MHz印刷偶极子天线的结构设计,给出了等效电路模型和具体的设计尺寸和仿真结果;然后使用分支线结构加载的方法进行小型化设计,设计结果为在中心工作频率915MHz处,增益为2.15dBi,电压驻波比小于1.5的工作带宽为78MHz,尺寸减缩幅度达48%以上;最后,在一定的柱面共形半径条件下,对上述印刷偶极子天线进行仿真,结果表明该天线仍能保持较好的工作性能,可以广泛应用于弹体共形等情况。

印刷偶极子天线实现全向辐射的一种设计方法

印刷偶极子天线由于具有体积小、频带宽等优点而被广泛用于许多领域。针对在某些场合需要E面全向辐射天线,设计了一个平面结构的宽带阵列天线,并利用电磁仿真软件HFSS进行仿真。天线采用了巴伦馈电的印刷偶极子作为基本单元,通过引入平面喇叭和反射单元来改善方向图不圆度,使其能在E面实现全向辐射。结果表明,它在3.5～6.5GHz的宽频率范围内的回波损耗基本在-10dB以下,E面方向图不圆度小于3dB,仿真与实测结果能够较好地吻合。