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。     

一种新型共面波导馈电单极子天线的设计与仿真

设计了一种简单的共面波导馈电单极子天线,给出了实验设计与仿真结果。结果表明,该天线具有良好的辐射特性,可覆盖GSM900、DCS1800、IEEE802.11.a、IEEE802.11.b和HiperLAN-2带宽。该天线体积小,尺寸仅为32mmx31mmx1.6mm,基板的介电常数为4.4。     

应用于WLAN/WiMAX/5G的CPW馈电三频天线设计

提出并制造一种应用于WLAN、WiMAX和5G系统的紧凑型共面波导(CPW)馈电三频天线.为了实现三频工作,分别将两个条带与主辐射矩形贴片和共面波导地面相结合.天线印刷在1.6 mm厚的FR-4基板上,整体尺寸仅为20 mm×30 mm×1.6 mm.天线实测和仿真测试有良好的吻合性,矢量网络分析仪测试结果表明,该天线在2.22～2.56 GHz、3.32～3.70 GHz和4.69～7.39 GHz内回波损耗小于-10 dB,在工作频段内有良好的增益.相比其他多频天线,该天线结构紧凑、简单.     

共面波导馈电平面小型化超宽带天线设计

超宽带(UWB)系统的工作频段与现有的全球微波互联网接入(Wi MAX)、无线局域网络(WLAN)系统等窄带系统的频段相互重叠,会导致系统相互干扰。为了有效抑制现有窄带系统对超宽带通信系统的干扰,在单极子天线的基础上,通过在带有L型分支结构的矩形辐射贴片上开槽的方法,设计了一款具有双陷波的超宽带天线。当电压驻波比小于2时,天线工作频率范围是2.5~16 GHz,其阻抗带宽为13.5 GHz。该天线最大的特点是在Wi MAX(3.4~3.69 GHz)以及WLAN(5.15~5.825 GHz)的频率范围具有双陷波特性,能够降低Wi MAX和WLAN对系统的干扰。同时,天线采用共面波导馈电,具有良好的共面特性。仿真和测试结果表明:该天线在超宽带频率范围内具有良好的陷波特性,能有效抑制现有其他窄带系统的干扰。与传统的超宽带天线相比,该天线在尺寸和带宽上具有很明显的优势。     

基于矩量法的小型化宽带线天线的仿真研究

研究了线天线的宽带化和小型化问题.针对目前通信技术的发展,各种电子设备均向小型化与微小型化方向发展,多频段和宽带跳频对带宽的需求,而常用的双极子天线由于带宽窄和物理尺寸大,无法满足天线小型化和宽带化的要求.提出了宽带匹配网络与加载相结合的方法设计了一种单极子加载天线,通过仿真详细分析了天线的电压驻波比和辐射特性,得出这种单极子加载线天线全面提高天线增益和降低电压驻波比的结果,经实验证明单极子加载天线基本满足小型宽带线天线要求.     

一种共面波导馈电的分形缝隙宽带天线

结合共面波导馈电和分形天线的优点,设计了一种共面波导馈电的正六边形分形缝隙天线。选择正六边形分形缝隙结构,采用渐变的共面波导馈电,不仅拓宽了阻抗带宽,而且实现了天线的小型化。通过计算测量,对天线的阻抗特性、增益和方向图进行了研究。实验表明,此分形缝隙天线的阻抗带宽达到89%,并且在整个工作频段内具有良好的辐射方向特性。     

双频共面波导天线设计

本文提出了一种基于共面波导结构的工作频率在2.45GHz和5.8GHz的双频带天线的设计。该天线采用了增加突出结构和边缘开槽的方法,通过时域有限差分法(FDTD)对共面波导尺寸的变化进行了仿真与优化,得出了共面波导结构对天线性能的影响,从而给出了相应的结构尺寸。并实际测量了天线的反射参数以及方向图,对比测量结果与仿真结果基本符合。最后本文对本次天线设计做出总结并对测量结果做了误差分析。     

双频共面电容耦合对称低轮廓微带天线的研究

本文提出了一款双频共面电容耦合对称低轮廓微带天线。该天线将同轴探针馈电方式与耦合馈电方式进行了有效的结合,融合共面、地轮廓等要素,制作出一款适用于WLAN系统的微带天线。本文在设计优化天线结构的基础上,制作了一款共面电容耦合对称低轮廓微带天线,并经过网络分析仪等测试仪器进行测试,结果表明:该天线适用于WLAN双频系统中。     

基于基片集成波导和消逝模谐振腔的压力传感器设计

提出一种新型的基于基片集成波导和消失模谐振腔的压力传感结构。设计了圆形空腔,当施加外界压力时,圆形空腔发生形变从而使谐振腔谐振频率变化。采用共面波导线对谐振腔进行耦合馈电并将频率信号传输出来。通过读取传感器的回波损耗参数( S11)来表征压力与频率的关系。利用高频仿真软件HFSS对谐振腔进行了仿真设计和优化,设计尺寸为30 mm×30 mm×1.93 mm,与传统谐振腔相比体积明显减小。传感器基底为Rogers 4003C板材,采用PCB技术进行加工。搭建压力测试平台对传感器进行测试,结果表明在0~3 N的压力范围内变化100 MHz,绝对灵敏度为25 MHz/N。仿真和实测结果比较吻合,验证了所设计压力结构的有效性。     

双频共面电容耦合对称低轮廓微带天线的研究

本文提出了一款双频共面电容耦合对称低轮廓微带天线。该天线将同轴探针馈电方式与耦合馈电方式进行了有效的结合,融合共面、地轮廓等要素,制作出一款适用于WLAN系统的微带天线。本文在设计优化天线结构的基础上,制作了一款共面电容耦合对称低轮廓微带天线,并经过网络分析仪等测试仪器进行测试,结果表明:该天线适用于WLAN双频系统中。     

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.     

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.     

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.     

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.     

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。     

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.     

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.     

Compact CPW‐Fed slot antenna with harmonic suppression

A compact coplanar waveguide (CPW)‐fed uniplanar antenna with harmonic suppression characteristics is presented. The above characteristics are achieved by properly modifying the ground plane and adjusting the signal strip of an open‐ended CPW‐fed transmission line. The simulated and experimental characteristics of the antenna are presented, compared, and discussed. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.