一种应用于微波探测的双频天线的设计

为增加火灾探测天线频带范围,基于微带贴片天线,采用凹槽加载技术,设计了中心频率在Ku(12.4～18.0 GHz)波段的双频微带单元天线.利用HFSS软件对其建模、仿真及优化,结果表明,该单元天线在14.8 GHz和16.1 GHz时回波损失达到最小值,且回波损失小于-10 dB的带宽分别为600MHz和390 MHz.利用该单元天线,进而设计了一款2×2阵列天线,实测结果表明:该阵列天线具有很好的双频谐振特性,在14.3～14.9 GHz和15.7 ～16.1 GHz频带内既保留了原单元天线好的回波损耗特性,又提高了增益,使两个频段最大增益分别达到13.7 dBi和11.3 dBi.     

双频手机天线设计

本文设计了一种具有8个单元的MIMO天线,可在2.4～2.6 GHz和3.4～3.6 GHz范围内工作,适用于5G手机通信系统。首先设计一款基于倒F天线的单元双频天线,通过在倒F天线的基础上增加枝节来实现双频工作,通过弯折枝节设计来减小其所占空间,实现小型化设计。单元天线最大增益为6.3 dB,当它工作在2.5 GHz时天线效率约为94%;当它工作在3.5 GHz时,天线效率为83%。进一步地,通过将两个单元天线对称放置于地板上形成双频双天线MIMO结构。双频双天线最大增益为6.3 dB,该天线工作在2.5 GHz时效率为92%,工作在3.5 GHz时效率为82%。由于双天线间隔距离较大,所以它们之间的耦合度较小,隔离度均大于10 dB,满足设计要求。将各个天线单元分布在地板上下两侧,每侧各两个天线并呈对称分布实现双频四单元天线设计。该天线最大增益为6.1 dB,当它工作在2.5 GHz时天线效率为93.5%,当它工作在3.5 GHz时天线效率为75%。由于各个天线之间距离较大,所以它们拥有较好的隔离度。设计双频八单元天线,将八个单元天线分别位于地板上下左右侧,通过地板刻蚀L型缝隙的方...     

一种叠双菱形天线的改进设计

在对菱形天线结构和工作原理进行分析的基础上,为缩小天线尺寸结构,提高天线的方向和增益特性,设计了一种以2.4 GHz为中心工作频率的带反射板的叠双菱形天线。设计过程中利用VB软件制作了交互式天线计算器,方便天线尺寸参数的计算和优化调整,并使用4NEC软件搭建天线的模型及仿真优化。在天线测试平台上利用PNA3621网络分析仪对制作的天线进行了测试。测量结果表明,在2.35 GHz～2.45 GHz频率范围内,天线方向图较好,与仿真结果较为吻合,天线输入端电压驻波比和回波损耗较为理想。     

一种具有双陷波特性单极子超宽带天线的设计

提出了一种基于C/U形槽、具有双陷波特性的平面超宽带单极子印制天线。其天线的组成部分包括椭圆球拍形辐射贴片、微带馈电线和矩形地板。通过在球拍形辐射贴片蚀刻C形槽、馈电线蚀刻U形槽的方法,使天线在WiMAX(3.3~3.7GHz)和WLAN(5.15~5.825GHz)频段内具有双陷波性能。仿真和测量结果表明,这种新型天线在通频带(2.5~10.6GHz)内电压驻波比小于2,在2.9~3.9GHz和4.9~6.0GHz两个频段内电压驻波比大于5,阻带的频率可通过蚀刻槽的长、宽来调节。该天线的测试结果与仿真结果吻合良好,且尺寸小巧、结构简单、成本低,可应用于超宽带通信系统。     

面向5G高隔离度4单元MIMO手机天线设计

设计了一个4单元高隔离度手机天线,由4个辐射单元组成,辐射单元分别位于天线的4个角落。对天线辐射单元进行分析测试,测量天线辐射单元工作频段为3.43 GHz～3.86 GHz,覆盖5G移动通信测试频段。MIMO天线工作频段在端口回波损耗小于-10 dB阻抗带宽条件下,工作频段为3.45 GHz～3.64 GHz;在端口回波损耗小于-6 dB阻抗带宽条件下,天线工作频段为3.23 GHz～3.96 GHz。新设计的圆形开槽结构能减少天线和电子元器件耦合,并且天线具有良好的全向性和辐射特性。MIMO天线在3.2 GHz～4 GHz频率内,天线辐射效率为65%～73.4%。仿真表明,脑部辐射SAR(Specific Absorption Rate)参数小于1.6 W/kg,天线对人体影响较低。     

一种低剖面蝴蝶结型的毫米波天线设计天线

文章介绍了一种新型的蝴蝶型天线,该方案通过在两个梯形天线的两侧加两个环形天线从而实现为带天线的宽带化,文中并以28GHz天线为例,给出了仿真结果,最终生产的蝴蝶天线阵测试和仿真结果保持一致.     

电磁带隙的超宽带阻带天线设计

设计了一种电磁带隙(EBG)结构.根据实际应用要求,在一种超宽带微带天线上加载电磁带隙单元,设计出一种阻带天线.对天线的多个参数进行讨论并优化设计,根据仿真实验制作出天线实物.实验结果说明:天线在3.11～5.97 GHz的频带范围内,电压驻波比(VSWR)值大于2;在5.46 GHz处达到了9.23的峰值,阻带范围覆盖WiMAX (3.4～3.7 GHz),C-band (3.7～4.2 GHz),WLAN(5.15 ～5.35 GHz/5.725～5.825 GHz)这三个频段,且天线增益在阻带内明显降低.     

一种超宽带的毫米波天线的相位和方向图的研究

针本文介绍了一种新型的蝴蝶型天线,该方案通过在两个梯形天线的两侧加两个环形天线从而实现微带天线的宽带化并将该天线进行一维八阵子组合,通过调整相位来实现一维扫描的功能,文中并以28GHz天线为例,给出了仿真结果.     

用于认知无线电系统的陷波可重构超宽带天线

提出了一种可应用于认知无线电系统的新型陷波可重构超宽带缝隙天线,以改进矩形单极子天线为基本模型,采用切角的矩形地板,实现了2.9～12 GHz的超宽带特性。在改进的矩形辐射片上蚀刻由倒U形和H形组成的对称折叠槽,实现了陷波特性。通过切换3个PIN二极管的状态来改变折叠槽的形状和有效长度,实现了3个频段陷波可重构功能。该天线结构紧凑,便于加工制作,在认知无线电系统中有潜在应用价值。仿真和实测结果表明,该天线具有良好的辐射特性,在WiMAX (3.4～3.9 GHz)、WLAN (4.6～6.0 GHz)和X波段卫星通信(6.5～8.2 GHz)下行链路范围内具有3个可重构的频带陷波功能。     

一种新型的双频段圆极化可重构微带天线

在移动终端的狭小受限空间内,如何有效地利用频率资源、空间资源,提高通信系统的传输容量是研究热点,设计性能良好的可重构天线是一种有效手段。本文采用多环缝隙结构设计了一种新型的双频段圆极化可重构天线。它在MEMS开关的控制下,可在4.9GHz和5.8GHz两个频率上同时实现左旋和右旋圆极化,两个频带的相对带宽分别达到11.2%和13.8%,很好地实现了圆极化可重构天线的双频带特性,能够满足移动通信对多频技术的需求。     

Radiated cross‐polar levels and mutual coupling in patch radiators

This article presents the relation between the cross‐polar signal radiated by a dual feed patch antenna and the mutual coupling existing between the antenna feeds. The theoretical analysis is based on the S‐parameters of the antenna element, providing a clear understanding of the physical relation between cross‐polar level and coupling. Analytical expressions are given for the radiation pattern computation, including the cross‐polar level and the effect of higher order modes on the pattern. Finally, the results of the study are illustrated with measured patterns. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 342–352, 2000.     

Design of a 16‐beam pattern‐reconfigurable antenna for vehicular environment

This article presents the design of a multipattern antenna with pattern switching for vehicular communications. The proposed antenna has four triangular patches integrated onto a split square ring (SR) resonator to operate at two distinct frequencies, viz. 2.4 and 3.5 GHz. The proposed antenna is designed with a view to enhancing the link reliability of Wireless Local Area Network (WLAN), WiMax, and vehicle to vehicle communication frequencies. Each triangular patch is separately excited using a microstrip line feed to enable beam steering. The ground plane of the antenna is embedded with two SR slots to improve the bandwidth and radiation performance. Further gain enhancement is achieved by loading the antenna with a plane reflector located at a distance of 20 mm from the antenna's ground surface. In reality, this reflector is realized using the vehicle's roof which provides gain enhancement up to 5.2 dBi at 2.4 GHz and 4 dBi at 3.5 GHz. By exciting single to multiple ports sequentially 16 different radiation patterns are obtained, which provides high‐gain omnidirectional coverage. The prototype antenna is fabricated and the simulation results are verified using experimental measurements. From the results, it is evident that the proposed antenna is suitable for vehicular communication applications.     

Optically transparent broadband water antenna

In this article, we investigate an optically transparent broadband water antenna, which is composed of a cross‐shaped slot feeding structure and a thin layer of water supported by a transparent dielectric slab. This water antenna can be analyzed as an embedded stacked dielectric resonator (DR) antenna (DRA) mounted on a ground plane. Two distinct resonator modes—namely, DRA mode and dielectric‐loaded slot (DLS) mode—are excited to achieve a good impendence matching over a very wide frequency range. A prototype antenna is designed, fabricated, and measured. Measured results demonstrate that the designed water antenna exhibits a broad impedance bandwidth of about 37% from 1.07 to 1.56 GHz with antenna efficiency better than 65% and broadside radiation characteristics with low cross‐polarizations.     

Tunable dual band antenna with multipattern reconfiguration for vehicular applications

This article presents the design of a pattern switchable patch antenna for vehicular applications. The proposed antenna has a square patch that is divided into four triangular regions using diagonal rows of vias. The triangular regions are separately excited using a coaxial feed to achieve frequency and pattern reconfiguration. Each triangular section of the antenna has “U” shaped and inner rectangular strips to obtain two resonant frequencies of 2.4 and 3.5 GHz, respectively to cover the part of WLAN, WiMax, and car‐to‐car communication ranging from 3.4 to 3.8 GHz. In order to cover the maximum bandwidth of WLAN and WiMax standards, frequency tuning is done using a varactor diode. Upon exciting any one of the port, the antenna generates a tilted beam with a peak gain of 6.8 and 5.8 dBi at 2.45 and 3.5 GHz, respectively. A full azimuth beam coverage can be achieved by exciting the ports sequentially. The antenna is also capable of generating eight other beams using multiple feed excitations with the maximum gain of 8.4 and 9.4 dBi for the axial beam at 2.45 and 3.5 GHz, respectively.     

Design of a miniaturized planar half elliptical ultra‐wideband dipole using a concaved arm

This article presents the miniaturization of a planar half elliptical ultra‐wideband dipole. By simply placing a concaved arm in close proximity to the original structure, a 45% area reduction in terms of electrical wavelength can be achieved. The proposed antenna exhibits a wide measured return loss bandwidth of 2 to 9.9 GHz and omnidirectional radiation patterns across the band. The design features a footprint size of 41.5 × 41.5 mm² and an electrical size of 0.28λ × 0.28λ at 2 GHz. Compared with some previously reported planar designs, the proposed antenna presents a more compact electrical dimension and better or comparable bandwidth. Critical geometric parameters of the structure, particularly the concaved arm, are investigated to understand the miniaturization and operating mechanism of the design. Satisfactory correlation between the simulation and measurement data is obtained.     

Multiband antenna for mobile terminals

In this paper, a multiband antenna composed of a tri‐mode monopole, an open‐slot etched on the ground, and a parasitic strip is proposed for mobile terminals. The tri‐mode monopole excites three modes including 0.25 λ, 0.25 λ, and 0.75 λ modes at 0.9, 1.85, and 2.4 GHz respectively, and can cover the desired frequency band 1.7 to 2.7 GHz. The open slot etched on the ground can obtain better impedance matching at 0.9 GHz to cover 0.82 to 0.96 GHz. To further broaden the bandwidth of the low frequency, a parasitic open‐ended strip is used to introduce a new resonance to extend the lower frequency band to 0.69 GHz. The proposed antenna is simulated, fabricated and measured. The impedance bandwidths with S₁₁ better than ?6 dB are 270 MHz (0.69‐0.96 GHz) and 1.06 GHz (1.7‐2.76 GHz). The consistency between the measured and simulated results indicates that the proposed antenna is available for mobile phone applications.     

基于北斗的警犬天线设计及优化

为了有效完成铁路沿线的安全监测,基于北斗警犬状态远程监测系统应运而生,目前存在着监测系统中天线受环境影响大、接收性能差等问题,针对上述问题设计了一种平面微带天线。本文以单支节调配器为主线,以应用角度出发,分别对其平面及馈线弯折等情况进行了仿真分析,克服铁路特殊环境北斗天线安装困难、频带窄易受干扰等缺点。采用ANSOFT HFSS软件进行天线性能仿真,仿真结果表明,设计的北斗天线有效中心频率为1571MHz,电压驻波比小于1.5,符合警犬状态远程监测的实际应用要求。     

Recent developments in bandwidth improvement of dielectric resonator antennas

This article shows a compressed chronological overview of dielectric resonator antennas (DRAs) emphasizing the developments targeting to bandwidth performance characteristics in last three and half decades. The research articles available in open literature give strong information about the innovation and rapid developments of DRAs since 1980s. The sole intention of this review article is to, (a) highlight the novel researchers and to analyze their effective and innovative research carried out on DRA for the furtherance of its performance in terms of only bandwidth and bandwidth with other characteristics, (b) give a practical prediction of future of DRA as per the past and current state‐of‐art condition, and (c) provide a conceptual support to the antenna modelers for further innovations as well as miniaturization of the existing ones. In addition some of the significant observations made during the review can be noted as follows; (a) hybrid shape DRAs with Sierpinski and Minkowski fractal DRAs seems comfortable in obtaining wideband as well as multiband, (b) combination of multiple resonant modes (preferably lower modes) can lead to wider impedance bandwidth, (c) at proper matching wider patch with slotted dielectric resonator can exhibit better bandwidth.     

Wideband microstrip‐based wearable antenna backed with full ground plane

A wideband microstrip‐based wearable antenna with a fractional bandwidth of 51% is designed using textile materials for wearable applications. The antenna operates between 2 and 3 GHz with low back‐radiation to ensure minimum coupling to the body and reduced electromagnetic power absorption in the human tissue. The behavior microstrip antenna topology, which is narrowband in nature, is altered via the combinations of various broadbanding techniques, while maintaining the existence of the full ground plane backing. This ensures that the antenna radiation is directed outward form the body to efficiently propagate wireless signals toward other off‐body nodes and base stations. Simulation and measurement results indicated that the use of this microstrip topology with multiple broadbanding techniques is capable of reducing the back lobe, resulting in a front‐to‐back ratio of about 17 dB and a 3.5 dBi of average gain.     

Design of a single null compensation dipole antenna

In this paper, a single null compensation dipole antenna for Wi‐Fi band (2.4 GHz) is developed. The antenna is fed by the parallel transmission lines, and its radiation unit consists of a printed dipole antenna and a Yagi antenna. The proposed antenna has three layers. The top and bottom layers are printed with the dipole antenna and the driver arm of the Yagi antenna. The director and the reflector of the Yagi antenna are placed on the middle layer. The three layers are separated by two FR‐4 substrates. This antenna satisfies the omnidirectional radiation characteristic in its H plane and can compensate a null point in the E plane. Simulation results show that the 10 dB bandwidth is 2.32 to 2.46 GHz. The maximum realized gain is 1.13 dB in the frequency band. The non‐roundness of the H plane is less than 2 dB, which shows good omni‐directivity. A null point in the radiation pattern of the E plane is compensated to ?1.4 dB at 2.4 GHz, while the other null point of the E plane remains below ?15 dB. The antenna has been manufactured and tested, and the measurement results validate the design and the simulation results.