A modified contour Integral analysis for Sierpinski fractal carpet antennas with and without electromagnetic band gap ground plane

A modified contour integral method coupled with segmentation method has been used, for the first time, to analyze both the Sierpinski fractal carpet (SFC) antennas of different orders and an SFC antenna with electromagnetic band gap (EBG) ground plane. The close agreement between the calculated and measured results for resonant frequencies and input return losses indicates that this technique can be used to accurately predict the impedance characteristic. A novel stacked microstrip Sierpinski carpet fractal antenna using the EBG ground plane is also presented. Comparing to an ordinary microstrip fractal antenna, which has a maximum bandwidth of approximately 2%, the proposed antenna has a higher input impedance bandwidth of nearly 9%. The radiation patterns of the proposed antenna are improved due to the removal of unwanted radiation caused by the surface wave. The experimental measurement results of the proposed antenna are presented in this paper.     

Analysis of Modified Square Sierpinski Gasket fractal microstrip antenna for Wireless communications

In this paper, the slot loaded microstrip antenna has been developed with Sierpinski gasket technique. The proposed Modified Square Sierpinski Gasket (MSSG) fractal antenna involves a square patch utilizing Sierpinski gasket (triangular) structure. Four triangular slots are loaded at each iteration. The structure is then simulated using commercially available Ansoft HFSS simulator. The multi-band operation has been achieved by the proposed antenna at 15.915 GHz, 20.045 GHz, 23.077 GHz, 27.77 GHz frequencies with −20 dB, −25 dB, −22 dB, −28 dB return loss respectively which works well for Ku (12–18 GHz) and K (18–27 GHz) band. The consistent result is obtained after simulation and the validity of fabricated design is checked by the measured result. The designed antenna is an attractive candidate for applications like wireless multi-band communication systems.     

微带双频蓝牙天线二种结构及性能比较

双频蓝牙天线的工作频率分别为2.4～2.5GHz和5.15～5.35GHz,提出了一种曲折臂倒F天线,对其进行了仿真,并加工出天线,测试结果表明,该天线与直臂天线性能基本一致,适合于蓝牙通信。     

Miniaturization of microstrip loop antenna for wireless applications based on metamaterial metasurface

The metamaterial and fractal techniques are two main methods for antenna miniaturization and in this paper, we have modeled an especial shape of the antenna based on loop formation with metamaterial load for this aim. The metamaterial layer is made by multi parallel rings and the result shows that the final antenna size reduced drastically while the frequency shifts from 7 to 4 GHz. The antenna has Omni-directional pattern with the gain of 3.5 dBi, so the size is reduced around 40%for 4.5 GHz and another resonance is made at 2.5 GHz with a return lossless than −6 dB with more than 60% frequency shift. The reflection and transmission have been utilized for showing the left hand characteristic based on two port periodic simulations in HFSS full wave software. We show that how the metamaterial load can provide the circular polarization (CP) by controlling the current distribution. We also presented that by making slots we obtained the better Axial Ratio (AR) and miniaturized the antenna with reconfigurable qualification. As a result of fact, we show that by using metasurface we able to miniaturized the antenna and simultaneously achieved the circular polarization.     

波导式双正-近零媒质加载双频微带天线

提出了一种基于嵌入式弯曲线(EML)和互补金属开口谐振环(CSRR)结构的波导式双正-近零分层 人工媒质,将其加载在微带贴片天线上以实现双频工作特性。理论分析以及仿真和实测结果表明:加载了分层人工 媒质的双频微带天线,两个最低阶谐振模式分别是TM010 和修正型TM020 模式,且该天线在这两个谐振频点上具有比 较一致的边射式辐射特性。本文提出的双频微带天线具有结构紧凑、易于用印刷电路板工艺进行一体化制造的优 点。     

K波段高增益超材料微带天线的拓扑优化设计

超材料微带天线的设计通常依赖经验,其中超材料基元的设计多以尺寸优化和形状优化为主。研究了常规超材料对微带天线增益性能的影响,发现其对增益性能的提升效果有限。提出了一种基于遗传算法的高增益超材料微带天线拓扑优化设计方法,对超材料基元采用整体设计的方法,以天线增益最大化为设计目标,以覆铜贴片方格子的有无为设计变量,建立了K波段(24 GHz)超材料微带天线的拓扑优化模型。进而基于遗传算法的求解策略,获得了一种新颖的超材料微带天线构型。仿真结果表明优化后的超材料微带天线侧向辐射得以抑制,其最大增益提升到10.5 dB,与普通微带天线相比性能提升了35%。同时通过改变覆铜贴片格子的布置规模对优化设计结果的收敛性进行分析,分析结果显示创新构型超材料微带天线设计结果是收敛的,且10*10方格子规模下的创新构型制备性价比最高。最后研究了超材料基元单独设计与整体设计的天线工作频率匹配对比,对比结果证实了超材料基元采用整体设计对于超材料微带天线拓扑优化是非常必要的。     

基于FSS 的双频高增益微带天线

设计并制作了一种基于双屏FSS(Frequency Selective Surface)部分反射表面的双频高增益微带天线。该FSS 结构是在介质板上下表面分别刻蚀两条方环形金属带,通过调节金属带的宽度,实现频比(Frequency Ratio,FR)达到2 的双频谐振,且在5. 12 ~5. 31GHz 和10. 08 ~10.84GHz 频带内反射相位曲线斜率为正(一般的为负),反射系数模值都在0. 86 和0. 82 以上。将FSS 以覆层的形式放置于双频微带天线上方,相当于增加了双频天线的辐射口径面积,有效改善天线的辐射性能。仿真和实测结果表明:与原始双频微带天线相比,加载双频FSS 覆层后,新天线的增益得到了提高,在5.22GHz 和10. 43GHz 处,天线鼻锥方向增益分别提高了4. 8dB 和5. 1dB。     

Compact and miniaturized microstrip antenna based on fractal and metamaterial loads with reconfigurable qualification

We have described a compact antenna based on fractal and metamaterial loads techniques. The microstrip patch antenna is assumed as a basic antenna and then the effect of fractal structures is implemented. The fractal patch is considered as a right-handed element and then by adding a left-handed element, the antenna miniaturization is achieved by using the metamaterial loads technique. The equivalent circuit is also used to describe the element effect on miniaturization and parametric models clarify them. The proposed antenna is modified for wireless applications and experimental results confirm our simulation results. In addition, we show that the proposed antenna is suitable for reconfigurable. By joining the unit cells together with various arrangements and changing the effective length, the various inductances can be obtained. Finally, by adding reconfigurable characteristic to the proposed antenna, the gain and radiation pattern can be controlled as shows in this paper. The patch antenna has low bandwidth and gain and so we have developed the patch antenna with defected ground to improve the bandwidth and the Frequency Selective Surface (FSS) is used to achieve higher gain and bandwidth. The final antenna is covering 2.4, 3.5 and 5.5 GHz with higher gain than the patch antenna.     

可用于物联网的高隔离度双频MIMO天线

设计了一种高隔离度双频多输入多输出（MIMO）天线,该天线覆盖2.4 GHz和5 GHz无线局域网频带,可以应用于移动物联网之中。天线包含两个相同的辐射单元天线,采用微带馈电的方式进行馈电。单元天线使用单极子天线作为基本辐射器,其包含一根长的和短的单极子天线,分别谐振在低频和高频频段。通过在两个单元天线中间加载T型隔离器提高了单元天线之间的隔离度。天线的辐射振子、馈电以及T型隔离器都印刷在同一块微波板材上,从而方便了天线的制作和加工。仿真结果表明,该天线在1.9~2.8 GHz以及4.7~6.2 GHz频带范围内能实现良好的双频工作特性,天线隔离度近20 dB,可以广泛应用于物联网系统中。     

Miniaturised reconfigurable window slot antenna using mechanical tuning

A novel design approach of varying the slot width on radiating patch of a microstrip antenna for achieving reconfigurable dual-band operation is proposed. The design of this miniaturised reconfigurable antenna is done without the use of active switches or MEMS. The dual band is obtained by rotating the strips on the patch creating slots and varying the slot width using mechanical tuning. The strip is rotated in angular position from 0° to 90° varying the slot width that alters the resonant frequency of the antenna making it resonate at different frequencies covering the wireless bands for global system for mobile communication, global positioning system, wireless local area network and Bluetooth. This antenna provides a dual-band operation that shifts over the bands depending upon the slot width. This antenna achieves the bandwidth requirement and gain in the bands of operation. The effect of change in slot width on the radiation pattern is also discussed. The prototype antenna is fabricated and tested to prove the proposed concept of design. The measured results are in agreement with the simulated results.     

Reconfigurable dual-band circularly polarized microstrip patch antenna for wireless applications

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.     

微带可重构天线的初步探讨

引入了一种崭新的天线概念-可重构天线。首先根据传统微带天线腔模理论定性地分析了微带可重构天线的工作机理，然后用时域有限差分（FDTD）法对微带天线的可重构特性进行了仿真分析。仿真和分析表明，矩形微带可重构天线当某一边长大于等于一个工作波长时，能够获得良好的可重构特性。     

Fractal stacked monopole with very wide bandwidth

A parallel feed stacked fractal antenna using the square Sierpinski and diamond Sierpinski carpet is introduced. The design achieves a good input impedance match throughout the passband (1-20 GHz) but occasional slight mismatch occurs. Three different experimental results are shown and the measured gain of these antennas is generally >0 dBi. These antennas are suitable for applications in picocell environments for the operating bands of GSM, DECT and WLAN systems     

基于非均匀特异媒质的赋形天线设计

在PCB板表面蚀刻不同尺寸的微带单元结构,构建非均匀特异媒质层,并将其放置在天线辐射单元前方,利用非均匀特异媒质层对电磁波不同的反射系数,实现对天线辐射波束的赋形。设计了由不同尺寸正方形贴片组成的非均匀特异媒质层,并放置于工作频率为5.8 GHz的矩形贴片天线前方。仿真和测试表明:该非均匀特异媒质层能够在基本保持贴片天线工作频点和回波损耗曲线不变条件下,通过调整与贴片天线距离,实现辐射波束由笔形波束向宽角波束和马鞍形波束的赋形转换。为赋形天线设计提供了一种有效的新方法。     

Design of a dual-band coplanar waveguide-fed slot antenna with wide frequency separation

This paper presents a novel design for a dual-band coplanar waveguide-fed-slot antenna that operates at 27GHz and 39GHz. Matching this antenna at the two widely separated frequencies is achieved using a special matching network of slot antennas. Experimental and numerical results are presented for the return loss and radiation patterns of this antenna.     

Analysis of microstrip fractal patch antenna for multi-bandcommunication [by FDTD]

The square microstrip fractal patch antenna in a Sierpinski carpet and the effects of its elements are analysed. The calculated results show that the multi-band frequency operation of the proposed antenna results from the driven element and not from the parasitic fractal elements     

一种小型陷波多用途超宽带天线

提出了一种小型陷波多用途超宽带微带天线。该天线与一般的宽缝隙微带天线类似,通过在矩形调谐支节上开V形缝隙获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.4到11GHz频段内驻波比小于2,在5.15~5.95 GHz范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

一种Ka/Ku双波段双极化共口径阵列天线

由于运载能力及卫星平台的限制,星载雷达要求雷达天线具有重量轻、功耗低、体积小、效率高等特点,尤其是对天线口径面积限制较为苛刻,双频段天线要想适用于星载条件,就必须考虑全新的结构形式。介绍了一种适应于星载条件的Ka/Ku双波段双极化共口径阵列天线,其中Ku波段天线双极化工作、Ka波段天线单极化工作。Ku波段天线阵采用了具有两阶零点滤波性能的微带耦合馈电辐射缝隙单元,这种天线单元具有易实现双极化、工作频带宽等优点。Ka波段天线阵采用侧馈微带帖片天线单元,其优点是易于实现与Ku波段天线共孔径。     

基于特异材料微带漏波天线辐射特性研究

分析复合左右手特异材料微带漏波天线的辐射原理,建立复合左右手材料微带漏波天线仿真模型,通过仿真计算得到微带漏波天线的辐射特性。制备与仿真参数相同的实物天线,测量天线S参数、方向图和天线各单元电容瞬态电压。最后,对仿真试验结果和实物天线测量结果比较,吻合较好。在固定工作频率下,复合左右手特异材料微带漏波天线工作在左手区时,电磁波辐射主要发生在天线结构前几个单元,且电磁波以指数形式快速衰减,工作在右手区时,电磁波沿整个天线辐射,且电磁波衰减较慢。     

Patch antennas with switchable slots (PASS) in wireless communications: concepts, designs, and applications

This feature article describes, in a comprehensive and unified fashion, the authors' work on the development of novel kinds of reconfigurable microstrip antennas: patch antennas with switchable slots (PASS). PASS are versatile for wireless communication systems, and their structure is very simple. This article introduces the operational mechanism of PASS, as well as their frequency-ratio control and input impedance tuning. Various PASS designs are presented to demonstrate the capability of PASS in wireless communication. These designs demonstrate the functions of dual-frequency operation, dual-band circular-polarization performance, and circular-polarization diversity with only one layer and a single feed. A practical PASS application for future Mars rover missions is also highlighted: a compact, dual-band, circularly polarized antenna for the UHF band was designed, fabricated, and measured, based on the PASS concept.