基于MEMS开关双频微带缝隙天线的设计

本文设计了一种基于MEMS开关的快速切换频率的双频微带缝隙天线.通过MEMS开关的通断来改变缝隙的尺寸,从而改变电流分布,实现天线谐振频率在2.4GHz和5.8GHz之间的快速切换.分析了MEMS开关状态与天线谐振频率之间的关系.仿真结果显示,当开关断开时,微带缝隙天线的频率为2.4GHz,回波损耗达到-27dB;当开关闭合时,微带天线工作频率切换到5.8 GHz,回波损耗达到-23dB,并通过实测数据验证了仿真结果.     

频率可重构的单极子天线设计

本文设计了一种频率可重构的单极子天线.天线由一个阶梯型馈线、两个L型枝节和一个矩形接地板组成.两个理想开关加载在馈线与枝节之间,通过控制开关状态改变天线的表面电流分布,从而实现频率可重构.天线的尺寸为35mm×40mm.仿真和测量结果表明:该天线可以在两个单频模式(2.4GHz和5.2GHz)以及一个双频模式(2.4GHz/5.2GHz)之间切换.天线在不同模式下都具有稳定的辐射方向图.     

应用于WLAN/WIMAX的宽频带单极子天线

针对应用于WLAN/WIMAX的双频和三频天线,通过构造6/9形辐射贴片和接地板开槽的方式,本文设计了一款结构简单的6/9形宽频带单极子天线.仿真结果表明:天线低频的相对带宽为14.8%(2.36~2.73 GHz),高频的相对带宽为52.8%(3.463~5.944 GHz).天线可同时接受WLAN(2.5/5.2/5.8GHz)和WIMAX(3.5/5.5GHz)等多个频率.在整个工作频带内天线的电压驻波比小于2.实测结果表明,加工的天线低频的谐振频率为2.58GHz,工作带宽为2.33~2.9GHz,相对带宽为22.1%(是仿真天线的1.46倍);高频的谐振频率为4.705GHz,工作带宽为3.45~5.96GHz,相对带宽为53.4%(是仿真天线的1.06倍),加工的天线比仿真模型的频段更宽.实现了一个结构简单且易于加工的天线设计,可以很好地接受WLAN/WIMAX的多个频率,且有较好的辐射特性,提高了天线的性能.     

陷波可重构的超宽带单极天线设计

本文提出了一个陷波可重构的超宽带单极天线.为了实现超宽带,辐射单元采用阶梯式结构.在辐射单元刻蚀一个开口缝隙,并在缝隙的适当位置放置三个开关,通过控制开关的不同组合状态实现陷波可重构.天线的尺寸为30mm×22mm(0.42λg×0.31λg,λg为低频导波波长).仿真和测量结果表明:天线可以工作在超宽带以及3个陷波可重构频段,超宽带工作频带为3.1GHz~10.7GHz,陷波频段涵盖3.4GHz~3.69GHz,3.7GHz~4.2GHz和5.2GHz~5.875GHz.     

一种双频MIMO天线的T型枝节解耦设计

本文设计了一种T型枝节解耦的双频MIMO天线.两个工作频段分别覆盖WLAN频率2.45 GHz/5.2 GHz/5.8 GHz.低频谐振单元为倒F天线,通过在低频枝节上增加短截线,用以产生高频谐振,实现双频工作.将天线单元沿水平方向对称放置形成二单元的MIMO天线,并采用在两个天线单元之间添加T型枝节的方法进行解耦.对...     

基于共面波导馈电的三频单极子天线

本文提出了一种新型的三频单极子天线,该天线用共面波导(CPW)馈电,由两个不同长度和结构的单极子构成,长单极子结构实现谐振频率1.57GHz和3.5GHz,短单极子结构实现谐振频率2.4GHz.同时,通过在左侧接地面上增加一个正方形贴片,改善了三个频段内的峰值增益.所实现的天线尺寸为59mm×40.55mm×1.6 mm,在三个工作频率上的带宽分别为254 MHz(1.518 GHz~1.772 GHz)、461 MHz(2.289GHz~2.75 GHz)和226 MHz(3.514 GHz~3.714 GHz),覆盖了GPS、无线局域网(WLAN)和无线接入系统等频段,增益分别为2.15dBi,3.12dBi和3.86dBi.     

基于中和线解耦的小型化MIMO天线设计

本文设计了一种利用中和线技术来提高隔离度的双频MIMO天线.天线单元采用印刷单极天线的形式,两个工作频段分别覆盖WLAN频率2.45 GHz/5.2 GHz/5.8 GHz.低频谐振单元为倒F天线,通过增加短截线,用以产生高频谐振,实现双频工作.在天线之间增加一个悬置的中和线来提高天线端口之间的隔离度.仿真结果表明,天线两个工作频带分别为2.39~2.53 GHz和4.57~6.09 GHz.天线两个端口之间的隔离度,在低频段内,S 21<-19.3 dB,在高频段内,S 21<-24.6 dB,满足移动通信WLAN频段天线的设计要求.     

探针馈电贴片天线的建模及其在滤波天线中的应用

针对探针馈电矩形微带贴片天线的建模,本文提出了一种新的集总元件等效电路,并给出了等效电路模型中元件参数的相关公式,尤其包含了馈电探针的位置参数.此等效电路的特点是其端口特性能够在比较宽的频率范围内与物理模型保持一致.为了验证该等效模型,以滤波器综合理论和所提出的等效电路模型为基础,设计了一个中心频率为2.4GHz,且具有二阶巴特沃尔斯带通滤波器响应的滤波天线,其中用提取好的2.4GHz探针馈电矩形微带贴片天线等效电路模型取代滤波器的末级谐振回路和端口.整个滤波天线的等效电路仿真结果与其物理结构仿真结果吻合较好,经实测得到的反射系数、方向图和增益也与仿真结果一致.     

基于双谐振环超表面的双波束天线

本文提出了一种基于双谐振环超表面的双波束天线.天线由两个相同的印刷偶极子贴片和超表面构成,超表面单元为双谐振环.该天线通过加载超表面实现了波束成形和波束偏转;同时,通过在偶极子贴片辐射臂旁边加入一排短路过孔,抑制了旁瓣,增加了波束的偏斜角度,还使天线的波束宽度变窄.另外,在基板上加载2×2的双谐振环阵列,提高了天线的增益.结果表明,天线谐振频率在3.5 GHz,-10 dB带宽为0.93 GHz,最大辐射波束指向(φ,θ)=(±155°, 90°),增益可达到8.02 dBi.     

一种平面宽带单极天线的设计

设计一种新颖的平面宽带单极天线。该天线由矩形平板单极天线变形而来,通过U形槽、增加和折叠天线两臂,实现小型化、多模和低驻波比特性(在1.71～1.96GHz和2.38～6.37GHz频段内VSWR小于2)。通过CST软件进行仿真,分析各谐振的电流分布和谐振长度。该天线结构简单,尺寸较小(60mm×20mm),制作容易,可用于GSM/WLAN/WIMAX应用。通过加工测试,天线的仿真结果和实测结果非常吻合。     

Reconfigurable patch-antenna design for wideband wireless communication systems

An effective design of a reconfigurable patch antenna, with a wide operational bandwidth for wireless communication and radar systems, is presented in this paper. The reconfigurable patch possesses an E-shaped structure and its operation frequency can be changed by integrated switches. The operational frequency of the antenna can cover an octave frequency range by utilising only two switch states. In state 1, the antenna operates from 9.2 GHz to 15.0 GHz and, in state 2, from 7.5 GHz to 10.7 GHz. Relative bandwidths of 48% and 35% are obtained in the two states, respectively     

Reconfigurable Compact Wideband Circularly Polarised Dielectric Resonator Antenna for Wireless Applications

In this work, a novel compact wideband reconfigurable circularly polarised (CP) dielectric resonator antenna (DRA) is presented. The L-shaped Dielectric resonator antenna is excited by an inverted question mark shaped feed. This arrangement of feed-line helps to generate two orthogonal modes inside the DR, which makes the design circularly polarised. A thin micro-strip line placed on the defected ground plane not only helps to generate a wideband response but also assist in the positioning of the two diode switches. These switches located at the left and right of the micro-strip line helps in performing two switching operations. The novel compact design offers the reconfigurability between 2.9–3.8 GHz which can be used for different important wireless applications. For the switching operation I, the achieved impedance bandwidth is 24% while axial ratio bandwidth (ARBW) is 42%. For this switching state, the design has 100% CP performance. Similarly, the switching operation II achieves 60% impedance bandwidth and 58.88% ARBW with 76.36% CP performance. The proposed design has a maximum measured gain of 3.4 dBi and 93% radiation efficiency. The proposed design is novel in terms of compactness and performance parameters. The prototype is fabricated for the performance analysis which shows that the simulated and measured results are in close agreement.     

CPW-fed ultra wideband slot antenna with arc-shaped stub

An ultra wideband coplanar waveguide (CPW) fed slot antenna is presented. A rectangular slot antenna is excited by a 50-CPW with an arc-shaped tuning stub. For the proposed antenna, the 210 dB return loss bandwidth could reach 15.6 GHz (3.7-19.3 GHz), which is about 135% with respect to the centre frequency of 11.5 GHz. Details of the antenna design, simulation and measured results on the return loss and the E-and H-plane radiation patterns of the proposed antenna are presented.     

Super Compact UWB Monopole Antenna for Small IoT Devices

This article introduces a novel, ultrawideband (UWB) planar monopole antenna printed on Roger RT/5880 substrate in a compact size for small Internet of Things (IoT) applications. The total electrical dimensions of the proposed compact UWB antenna are 0.19 λ_o × 0.215 λ_o × 0.0196 λ_o with the overall physical sizes of 15 mm × 17 mm × 1.548 mm at the lower resonance frequency of 3.8 GHz. The planar monopole antenna is fed through the linearly tapered microstrip line on a partially structured ground plane to achieve optimum impedance matching for UWB operation. The proposed compact UWB antenna has an operation bandwidth of 9.53 GHz from 3.026 GHz up to 12.556 GHz at −10 dB return loss with a fractional bandwidth (FBW) of about 122%. The numerically computed and experimentally measured results agree well in between. A detailed time-domain analysis is additionally accomplished to verify the radiation efficiency of the proposed antenna design for the ultra-wideband signal propagation. The fabricated prototype of a compact UWB antenna exhibits an omnidirectional radiation pattern with the low peak measured gain required of 2.55 dBi at 10 GHz and promising radiation efficiency of 90%. The proposed compact planar antenna has technical potential to be utilized in UWB and IoT applications.     

A Compact 28 GHz Millimeter Wave Antenna for Future Wireless Communication

This article presents a novel modified chuck wagon dinner bell shaped millimeter wave (mm-wave) antenna at 28 GHz. The proposed design has ultra-thin Rogers 5880 substrate with relative permittivity of 2.2. The design consists of T shaped resonating elements and two open ended side stubs. The desired 28 GHz frequency response is achieved by careful parametric modeling of the proposed structure. The maximum achieved single element gain at the desired resonance frequency is 3.45 dBi. The efficiency of the proposed design over the operating band is more than 88%. The impedance bandwidth achieved for −10 dB reference value is nearly 2.9 GHz. The proposed antenna is transformed into four element linear array which increases the gain up to 10.5 dBi. The fabricated prototype is tested for the measured results. It is observed that measured results closely match the simulated results. By considering its simple structure and focused radiation patterns, the proposed design is well suited for IoT (Internet of Things), mmWave microwave sensing, 5G and future RF (Radio Frequency) front-ends.     

A novel design of a cpw‐fed single square‐loop antenna for circular polarization

Abstract

The experimental and simulated results for the proposed antenna are investigated in this article. Moreover, a novel broadband design of a circularly polarized (CP) single square slot antenna fed by a single coplanar waveguide is presented. By appropriately choosing the circumference of the square‐loop, the length of the protruded strip, and the gap, this proposed antenna thus owns good CP radiation and good impedance match simultaneously at the frequency of 2.45 GHz. This proposed antenna has the fundamental resonant frequency of 2.5 GHz with the minimum return loss of ‐39.9 dB. Furthermore, its impedance bandwidth is 460 MHz or 18.4% and 3‐dB axial‐ratio (AR) bandwidth is 360 MHz or 14.4% at 2.5 GHz.     

A Compact Flexible Circularly Polarized Implantable Antenna forBiotelemetry Applications

With the help of in-body antennas, the wireless communication among the implantable medical devices (IMDs) and exterior monitoring equipment, the telemetry system has brought us many benefits. Thus, a very thin-profile circularly polarized (CP) in-body antenna, functioning in ISM band at 2.45 GHz, is proposed. A tapered coplanar waveguide (CPW) method is used to excite the antenna. The radiator contains a pentagonal shape with five horizontal slits inside to obtain a circular polarization behavior. A bendable Roger Duroid RT5880 material (ε_r = 2.2, tanδ = 0.0009) with a typical 0.25 mm-thickness is used as a substrate. The proposed antenna has a total volume of 21 × 13 × 0.25 mm³. The antenna covers up a bandwidth of 2.38 to 2.53 GHz (150 MHz) in vacuum, while in skin tissue it covers 1.56 to 2.72 GHz (1.16 GHz) and in the muscle tissue covers 2.16 to 3.17 GHz (1.01 GHz). GHz). The flexion analysis in the x and y axes was also performed in simulation as the proposed antenna works with a wider bandwidth in the skin and muscle tissue. The simulation and the curved antenna measurements turned out to be in good agreement. The impedance bandwidth of −10 dB and the axis ratio bandwidth of 3 dB (AR) are measured on the skin and imitative gel of the pig at 27.78% and 35.5%, 13.5% and 4.9%, respectively, at a frequency of 2.45 GHz. The simulations revealed that the specific absorption rate (SAR) in the skin is 0.634 and 0.914 W/kg in muscle on 1g-tissue. The recommended SAR values are below the limits set by the federal communications commission (FCC). Finally, the proposed low-profile implantable antenna has achieved very compact size, flexibility, lower SAR values, high gain, higher impedance and axis ratio bandwidths in the skin and muscle tissues of the human body. This antenna is smaller in size and a good applicant for application in medical implants.     

Design of a Compact Monopole Antenna for UWB Applications

In this paper, a low cost, highly efficient and low profile monopole antenna for ultra-wideband (UWB) applications is presented. A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency. To design the proposed structure, three steps are utilized to achieve an UWB response. The bandwidth of the proposed antenna is improved with changing meander lines parameters, miniaturization of the ground width and optimization of the feeding line. The measured and simulated frequency band ranges from 3.2 to 12 GHz, while the radiation patterns are measured at 4, 5.3, 6 and 8 GHz frequency bands. The overall volume of the proposed antenna is 26 × 25 × 1.6 mm3 ; whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025, correspondingly. The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98% for the entire wideband. Design modelling of proposed antenna is performed in ANSYS HFSS 13 software. A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.     

Ultra wideband patch antenna with a novel folded-patch technique

The authors present the results of a polygonal patch antenna for ultra-wideband applications covering a frequency band from 4.14 to 13.50 GHz. The fabricated antenna achieved a 210 dB impedance bandwidth in excess of 125% with an antenna size of 0.373λo/sub / x 0.373 xλo/sub /0.149λ/spl o/ at its centre frequency. The antenna?s impedance bandwidth is 64% higher than what is currently obtainable with state-of-the-art folded-patch techniques. The proposed patch antenna has a polygonal-shape with a rectangular slot and shorting pins. The analysis of this antenna shows that bandwidth broadening is achieved by using a rectangular slot on the patch that is fed from a folded-patch feed, whereas the reduction in antenna size is achieved through the use of two shorting pins strategically located on the radiating patch.     

小型化超宽带微带天线的设计

本文提出了一种结构简单的小型化超宽带微带天线,尺寸为28mm×30mm．天线采用渐变馈线对酒杯状贴片馈电,接地板采用缺陷地的结构．天线参数采用电磁仿真软件CST进行仿真和优化．测量结果显示该天线在S11小于-10dB时,相对带宽是170．1％（2．4GHz～30GHz）．实际制作了天线的样品并进行了测试,实测与仿真吻合良好．