Low-profile patch antennas for biomedical and wireless applications

Printed microstrip-fed antennas based on a slotted radiating patch are proposed herein. First, a basic rectangular antenna without any slots was designed, being suitable for wideband applications and showing impedance bandwidth of 2714 MHz for \(S_{11} < -10\) dB. Next, dual-band operation for worldwide interoperability for microwave access (WiMAX, from 3.11 to 3.97 GHz) and wireless local-area network (WLAN, 4.97–5.71 GHz) was obtained by including slots only on the left side of the basic design. Then, using a structure with slots on the right side of the radiating patch, WLAN operation was obtained in the frequency range of 2.865–2.096 GHz. The fourth antenna, with slots on both sides of the patch, was characterized and realized for biomedical applications at 2.45 GHz (\(S_{11} <-10\) dB). The proposed antennas can be realized with small ground plane size and total antenna area of only \(27.5 \times 21\,\hbox {mm}^{2}\). This reduction in total antenna area is achieved by using a truncated patch. All the simulations were carried out using Empire XCcel. The designs were characterized based on their radiation pattern, return loss, voltage standing wave ratio (VSWR), gain, and current distribution. The simulated and measured results show good compatibility.     

Miniaturized modified circular patch monopole antenna on ceramic-polytetrafluroethylene composite material substrate

A 0.22λ×0.29λ×0.03λ miniaturized modified circular patch monopole antenna on high permittivity ceramic-Polytetrafluoroethylene (PTFE) composite material substrate is presented. The proposed antenna is designed and investigated using 3D full wave high frequency electromagnetic simulator and fabricated using printed circuit board (PCB) prototyping machine. Impedance bandwidths (Reflection coefficient <?10 dB) of 26.76 % (5.0–6.3 GHz), 5.3 % (9.1–9.6 GHz) and 3.6 % (10.7–11 GHz) have measured. Average gains of 0.9 dBi, 3.68 dBi and 3.63 dBi measured at first, second and third band correspondingly. 87.3 %, 88.5 % and 93.1 % radiation efficiencies have achieved at three resonant frequencies 5.6 GHz, 9.5 GHz and 10.9 GHz respectively. The measured symmetric and nearly consistent radiation pattern makes the proposed antenna suitable for C band and X band applications. In this letter, the effects of dielectric properties of substrate material and design parameters have studied.     

A miniaturized slotted multiband antenna for wireless applications

A novel miniaturized slotted multiband antenna is presented in this article. The antenna consists of a kite-shaped slot in the radiating patch to obtain miniaturization, C- and G-shaped slots in the ground plane to incorporate multiband operation and a microstrip feedline to obtain an impedance matching. The aforementioned miniaturization method results in about 50% reduction in active patch area and about 36% reduction in volume of the proposed design, as compared to the conventional antenna. G-shaped slot is used to obtain operations at 3.6 and 5.8 GHz, while C-Shaped slot is used to obtain operations at 6.9 and 9.5 GHz. The antenna has an active patch area of only 384 \(\hbox {mm}^{2} (24\times 16\,\hbox {mm}^{2})\), and the entire performance analysis of the antenna are carried out using HFSS v.13.0 simulation software. The proposed design operates at about 3.58 (WiMAX), 5.9 (WLAN), 6.72 (Satellite TV), 8.51 and 9.76 GHz (X-band) with \({S}_{11}<-\,10\,\hbox {dB}\) bandwidth of about 1.95% (3.54–3.61 GHz), 3.5% (5.88–6.09 GHz), 1.7% (6.68–6.80 GHz), 4.4% (8.36–8.74 GHz) and 3.96% (9.4–9.78 GHz), respectively. The proposed structure is compact in size, simple in construction, low profile, easy to fabricate, exhibits good impedance matching, moderate gain and stable radiation characteristics across the operational bandwidths.     

Gain enhancement and broadband RCS reduction of a circularly polarized aperture-coupled annular-slot antenna using metasurface

A circularly polarized microstrip slot antenna with low radar cross-section (RCS) and high gain was designed using a metasurface composed of a \(6 \times 6\) array of corner-truncated square patches placed on top of the upper substrate. By optimizing the geometry of the metasurface patches and L-shaped feed of the proposed antenna, broadband RCS reduction and improved overall antenna performance were achieved. A prototype antenna was fabricated, and the results showed that the proposed antenna exhibited an impedance bandwidth of 29.08 % in the frequency band of 4.29–5.75 GHz. The designed antenna achieved good 3-dB axial ratio (AR) bandwidth of about 30.18 % with center frequency of 5.3 GHz, and gain in the broadside direction of 9.9 dBi. Using the designed metasurface, remarkable monostatic RCS reduction was obtained in the frequency range from 4 to 13 GHz.     

Small-size scarecrow-shaped CPW and microstrip-line-fed UWB antennas

In this paper, a scarecrow-shaped ultrawideband (UWB) antenna is presented using CPW and microstrip line feeding. The physical dimensions of the proposed antennas are \(25 \times 20 \times 1.6\,\hbox { mm}^{3}\), in which the modification in the ground is made by etching two half-circle and square slots symmetrical with respect to center feed line. The measured impedance bandwidth (return loss \(<\,10\,\hbox {dB}\)) obtained for CPW-fed antenna is 147.13% (2.51–16.48 GHz), and for microstrip-line-fed antenna it is 139.88% (2.86–16.17 GHz). Various antenna parameters for both the designs are calculated, such as gain, radiation pattern and group delay which are quite acceptable for UWB applications. The proposed designs are first simulated by the CST Microwave Studio, and optimized designs are fabricated. The simulated and measured results are compared for the validation of the design.     

基于新型缝隙单元的微带全向阵列天线设计

提出了一种新型串行馈电的全向缝隙阵列天线，在带状线两侧背靠背刻蚀8对圆环缝隙，在缝隙内部加载一个Y形缝隙，延长Y形缝隙的长，并在顶部刻蚀横槽，形成最终的Y-T型缝隙结构，用以提升单元辐射性能。采用遗传算法(GA)对阵列进一步优化，使其工作带宽进一步扩宽，增益有所提升。根据设计结果加工制作了天线样品，实际测试表明，天线的|S11|<-10 dB阻抗带宽为7.93% (5.56~6.02 GHz)，带宽内峰值增益均高于8.99 dBi。工作在5.8 GHz处，E面旁瓣水平低于-10.11 dB，峰值增益为9.43 dBi, 且有稳定的全向辐射性能。     

表面开槽的宽带遥测微带天线设计

微带天线由于体积小、易共形、适用于金属环境等优点而被广泛地应用于旋转件遥测系统中。针对传统微带遥测天线带宽较窄的问题,本文提出了一种通过在天线贴片和地板上开槽来扩展带宽的设计方法,并进行了仿真和测试验证,二者结果吻合良好。高频电磁结构仿真软件HFSS的仿真结果表明,通过在适当位置开槽,可使得天线的相对阻抗带宽(S11<-10dB)达到5.6%(2.409~2.545GHz),基本覆盖ISM频段,最高增益可达4dBi。测试结果表明其相对阻抗带宽为6%(2.41~2.56GHz),在收发天线间距10毫米的情况下,传输系数S21达到-22dB,可以满足遥测系统的需求。     

应用于ISM频段的小型双频微带天线

针对现代无线通信系统小型化、便携式的发展趋势,提出了一种新型的应用于ISM频段的小型双频微带天线,该天线成功覆盖了部分ISM频段(433.05~434.79MHz、2.4~2.5GHz)。蜿蜒的曲流结构,使得电流分布长度增加,从而使天线尺寸成功缩小到30mm×25mm内。加载技术的应用,实现了天线的双频特征。根据天线尺寸,做出了实物并与仿真结果进行比对。测得实际带宽:低频部分(428~440.6 MHz)、高频部分(2.39~2.51GHz);实际增益:低频部分为-4.11dBi、高频部分为1.57dBi,与仿真结果基本吻合。     

Analysis of a dual‐resonant multiple split‐ring patch antenna

The design and analysis of a new 0.06λ × 0.09λ compact circular polarized square‐shaped dual‐resonant multiple split‐ring patch antenna on a 1.905‐mm‐thick high‐dielectric ceramic–polytetrafluoroethylene composite is presented. The proposed antenna was designed and analyzed by using a high‐frequency electromagnetic simulator based on the finite element method and was fabricated on a printed circuit board. The measured ?10 dB return loss bandwidths were 44.44% (0.7–1.1 GHz) and 34% (2.25–3.1 GHz) at 0.9 and 2.5 GHz center frequencies, respectively. The measured radiation patterns with 5.9 and 4.0 dBi maximum gains were symmetric and steady, making the proposed antenna suitable for radio frequency identification, wireless local area network, wireless body area network, Low Rate‐Wireless Personal Area Network (LR‐WPAN), and so on. The effects of linewidth, dielectric property of the substrate materials, and number of split rings on the return loss were investigated. The surface current distribution over the radiating patch and the characteristics of the Resistance, Inductance, Capacitance (RLC) equivalent circuit of the proposed antenna were also analyzed. Copyright © 2013 John Wiley & Sons, Ltd.     

Duo triangle-shaped rectangular microstrip-fed patch antennas input and output parameters investigation

Conventional rectangular microstrip-fed patch antennas are initially investigated numerically within the frequency band 2.0 to 2.8 GHz for Wi-Fi applications. In order to enhance the input parameters of the underlying antennas, three prototypes are designed. A split is diagonally loaded on a conventional radiating patch to achieve a duo triangle-shaped microstrip-fed patch antenna in the first step. The conducting ground plane of the conventional and the duo triangle-shaped patches is modified to design the microstrip-fed monopole and duo triangle-shaped monopole antennas in the second and third steps, respectively, within the frequency band of 2.0 to 7.0 GHz. Concepts of voltage and current waves as well as classical electrostatics approach solutions are used to, respectively, investigate the return loss bandwidth and the electric field radiation pattern of the proposed antennas. Numerical simulations show some relevant antenna performances such as a triple-band, a −10-dB return loss bandwidth of 29% , a gain of 7.5 dB, and a calculated half power beam width of 120^° in E-plane.     

L波段多频微带天线设计

为了实现在L波段激励起多个谐振点,并利用各个谐振点尖锐的选择性以提高系统的抗干扰性,采用在圆形辐射贴片上开圆环形缝隙,同时加载2个短路片的设计方法,设计一款工作于L波段的多频微带天线.通过3维电磁仿真工具HFSS进行实验,其结果表明:当两个短路片的夹角为90°正交,而且馈电点距离圆心的距离为25 mm时,天线产生3个谐振频点:1.3、1.53、1.67 GHz;低频点与高频点的频差可达370 MHz.这种多频点天线适合于跳频与多频通信系统,而且其高度只有1 mm,符合平面化应用的需求.     

一种平面小型化超宽带天线的设计

提出了1款小型化单极子超宽带天线。该天线印刷在厚度h=1.0mm,介电常数εr=4.4的FR-4环氧树脂介质板上,主要由类似矩形辐射面、阶梯型接地面组成,总尺寸为33mm×28mm×1mm,满足小型化的设计要求。天线具有3.1～12.5GHz的可用超宽工作带宽(相对带宽达到120.5%)、良好的全向辐射特性、较高的增益和较小的群延时。同时,为了抑制来自全球微波互联接入系统(Wimax,3.3～3.6GHz)或无线局域网系统(WLAN,5.15～5.35GHz,5.75～5.825GHz)的干扰,利用在矩形辐射单元上蚀刻不同长度的C型槽的方法,使天线分别在频谱3.16～3.93GHz或5.11～5.89GHz上具有带陷特性。另外,文中给出了超宽带辐射单元尺寸和陷波槽总长度的估算方法。     

用于检测电气设备电晕的盘锥天线的研制

为实现对变电站内电气设备电晕放电的检测,研究并设计了宽频带、高增益和水平面(H面)全向性的天线作为电晕检测的传感器。通过分析盘锥天线的辐射特性和特性阻抗,确定其设计为电晕检测天线具有优势,用离散化方法加工出的盘锥天线,在10MHz～1GHz以上具有良好的频率响应特性,平均增益4dB以上,在变电站检测试验中表现出良好的电晕放电信号接收能力。基于该天线可以开发出固定式或车载式电晕监测和定位系统,该系统可以监测整个变电站设备的电晕情况并且其工作不与设备发生接触。     

低成本宽带高效率堆叠贴片天线

为克服合成孔径雷达中现有微带天线带宽窄、效率低、成本高的缺陷,提出了一种在低成本FR4基板上实现的X波段宽带高效堆叠微带贴片天线。天线通过多层FR4基板堆叠方式构成,通过空气腔的引入,天线的有效介电常数和介质损耗得到降低,天线的效率和带宽得到提升。利用寄生贴片在带内增加了谐振点,使得天线的带宽得到进一步增大。同时为补偿馈电探针的寄生电感,利用微带匹配器对天线的输入阻抗进行匹配。实测表明,天线输入驻波低于2.0的频率范围为7.7~11.7GHz,相对带宽大于40%。天线的增益为7.6dBi,效率为83%。与传统微带贴片天线相比,具有宽带、高效、低成本的特点,具有一定应用前景。     

CPW‐fed compact thin‐film UWB antenna with dual band‐notched characteristics

This paper presents a new compact thin‐film ultrawideband (UWB) antenna with dual band‐notched characteristics. The antenna contains a rectangular slot with a fork‐like tuning stub. To achieve the dual band‐notched characteristics, narrow and U‐shaped slots are inserted on the radiator. This antenna is printed on a Mylar film substrate of 0.3 mm thickness with a dielectric constant of 3.2. The antenna has compact dimensions of 34.5 × 27.3 mm². It operates in the frequency range 2.9–11.3 GHz with impedance matching covering the entire bandwidth and reasonable radiation properties. It also exhibits dual band‐notched characteristics. One of the notched frequencies is in the range 3.3–3.7 GHz (WiMAX band) and the other in the range 5.1–5.8 GHz (WLAN band). The antenna is designed and simulated by using the commercial IE3D software, which is based on the method of moments. The antenna was fabricated and measured using Agilent E363B PNA network analyzers. The characteristics of the fabricated antenna show high correlation with those obtained from the simulation. The results confirm that the proposed antenna can achieve notch performance for WLAN and WiMAX communication systems and is also suitable for various portable UWB applications. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

An accurate computation method based on artificial neural networks with different learning algorithms for resonant frequency of annular ring microstrip antennas

An annular ring compact microstrip antenna (ARCMA) constructed by loading a circular slot in the center of the circular patch antenna is a popular microstrip antenna due to its favorable properties. In this study, a method based artificial neural networks (ANNs) has been firstly applied for the computing the resonant frequency of ARCMAs. Multilayered perceptron model based on feed forward back propagation ANN has been utilized, and the constructed model have been separately trained with 8 different learning algorithms to achieve the best results regarding the resonant frequency of ARCMAs at dominant mode. To this end, the resonant frequencies of 80 ARCMAs with varied dimensions and electrical parameters in accordance with UHF band covering GSM, LTE, WLAN and WiMAX applications were simulated with a robust numerical electromagnetic computational tool, \(\hbox {IE3D}^\mathrm{TM}\) , which is based on method of moment. Then, ANN model was constructed with the simulation data, by using 70 ARCMAs for training and the remaining 10 for test. As the performances of the 8 learning algorithms are compared with each other, the best result is obtained with Levenberg–Marquardt algorithm. The proposed ANN model were confirmed by comparing with the suggestions reported elsewhere via measurement data published earlier in the literature, and they have further validated on an ARCMA fabricated in this study. The results achieved in this study show that ANN model learning with LM algorithm can be successfully used to compute the resonant frequency of ARCMAs without involving any sophisticated methods.     

高速动车组车载双频天线设计与布局研究

针对动车组内无线通信质量问题,在微带线的基础上运用分枝法,设计出满足高速列车车载要求的双频单极子天线。天线尺寸为23mm×36mm×1.3mm,最大增益为3.8dBi,其工作频段为2.28~2.64GHz和5.47~6.15GHz,在2.4GHz和5.8GHz频段相对带宽分别为14.6%和11.7%,覆盖ISM频段。以CRH380A型动车组内部环境为研究对象,运用CST电磁仿真软件,建立车厢内部车载天线布局仿真模型。同时,将车内传输效果与自由空间进行对比。各BSS内的天线传输系数在ISM频段内位于-20~-50dB之间,RSRP属于最优等级Ⅰ。验证了所设计天线的有效性及其布局的可靠性。研究结果对动车组车载天线设计以及车内天线布局有很好的参考价值。     

The design of linear and circular polarization for dual band microstrip slot antenna

This paper presents a lightweight antenna for wireless communication systems. The proposed antenna has been designed to be a dual‐band and dual‐polarized antenna by using a right‐angled slot structure fed a by microstrip line. The designed antenna is composed of three right‐angled slot radiators on the ground plane. The first two radiators are right‐angled slots of similar scale which are added to generate circular polarization at 4.95 GHz, while the last one has been designed for linear polarization at 2.45 GHz. Furthermore, in order to achieve dual‐band operation and dual polarization with good matching, a special arrangement is proposed. The results of simulation and measurements such as return loss, axial ratio, and radiation patterns are shown at the resonant frequencies of 2.45 and 4.95 GHz. Details of the experimental results are presented and discussed. In addition, the presented antenna can operate and cover the applications of a wireless local area network (WLAN IEEE 802.11 a/b/g/j/n). © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

检测气体绝缘组合电器局部放电的四频段微带单极子特高频天线设计

针对用于气体绝缘组合电器(GIS)局部放电特高频(UHF)在线监测的天线传感器应具有宽频带、高增益和小尺寸等性能要求,设计了一种外置小型四频段微带单极子特高频天线传感器。采用多个辐射单元技术,展宽了特高频天线的检测频段,实现了传感器的多频信号传感特性,运用HFSS仿真软件对天线结构尺寸进行优化设计,选取一组最优参数进行特高频天线实物制作。理论计算和实验室天线特性实测表明,研制的外置四频段微带单极子特高频天线性能优异,在实验室GIS装置上,用已有的微带贴片特高频天线与所设计的特高频天线传感器对模拟缺陷产生的局放信号进行了对比检测,进一步证明了微带单极子特高频天线具有良好的检测灵敏度。     

一种宽频带RFID阅读器天线的设计

UHF RFID标签在密集布放环境下,会由于标签天线间的互相影响,使工作频率发生偏移,造成系统漏读.因而本文设计了一款新型的圆极化阅读器天线,该天线工作在UHF频段,具有小型化、高增益、宽频带的特点.其中主辐射圆形贴片通过4个探针与微带匹配网络上下相连,匹配网络的引入提高了天线的圆极化轴比和工作带宽.仿真结果表明,该天线在UHF频段的阻抗带宽和3 dB轴比带宽分别为13％和5％,增益高达9.4 dBi.在空旷的环境下,对密集布放的多个RFID标签进行读取测试.实验表明,运用宽频带的RFID阅读器天线可以有效地提高标签的读取率.