基于PSO的E型双频天线自适应优化设计

研究天线性能优化问题,为了满足多个无线通信系统实现多系统收发共用,天线需在宽频带及不同频段下工作.为了得到优化的谐振频率和宽带,通过在矩形微带线上开两条对称的槽得到E型贴片天线,实现天线的双频功能,利用电磁仿真软件IE3D建立天线模型,通过IE3D对天线的性能进行仿真和分析,同时使用粒子群优化算法对其关键性参数进行了自适应优化,得出天线的具体尺寸.仿真结果表明,天线-10dB阻抗带宽分别为125 MHz(2400-2525MHz)和275MHz(5575-5850MHz),能够满足WLAN(2400-2484 MHz/5725-5825 MHz)的通信需求.优化的天线结构简单,具有很好的双频特性,在工作带宽内有很好的全向辐射特性.     

一种433MHz小型化螺旋形印刷天线的设计

采用微带线在介质基片上模仿螺旋天线的走线形式,设计了一种433 MHz小型化螺旋形印刷天线,减小了天线的结构尺寸。采用仿真软件HFSS对天线的主要结构参数进行分析和优化,推导出了天线的最佳结构参数,并通过加载无源集总元件的方法改进了天线的阻抗性能。对回波损耗、增益进行了研究,结果表明:S(1,1)<-10 dB的有效带宽为3.4 MHz(431.5 MHz~434.9 MHz),在433 MHz谐振频点处的S11为-24 dB,有效增益为-4.14 dB。     

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.     

一种超高频 RFID 标签天线结构分析

本文对一种超高频 RFID 标签天线结构进行了仿真分析,优化后的标签天线在负载芯片时,功率反射损耗小于-10dB 的频率范围是900MHz-931MHz,我国和美国允许的频段都包括在内,并且在915MHz 达到最小值-37dB.标签天线能够全向辐射,其远场的增益是2.08dBi.文中讨论了天线各部分尺寸对天线性能的影响,为优化天线的阻抗提供了依据.     

一种用于5G通信的双极化水平全向天线

目前,5G应用已迫在眉睫。笔者设计了一款由三天线单元组成的±45°极化水平全向天线,单元之间采用一分三功分器进行馈电,并利用HFSS软件进行仿真。经实际测验,3300～3800MHz所需频段,天线驻波小于1.8,覆盖了LTE 3400(3 400～3 600 MHz)和5G的Sub-6 GHz(3 300～3 600 MHz)频段,端口隔离小于-20 dB,天线在工作频段内的增益大于1.5 dBi,圆度小于5 dB。     

一种小型化宽频基站天线设计

随着无线通信技术的迅速发展,为了满足2G/3G/4G频段的覆盖,同时减小天线尺寸,本文提出了一种小型化宽频基站天线.该天线由一个低频辐射单元和高频辐射单元同轴嵌套而成,±45°双极化,低频辐射单元由两对偶极子构成,通过共用偶极子臂和辐射臂弯折,来实现天线小型化。天线仿真的-15dB阻抗频带为694-960MHz(相对带宽为32%)和1695-2690MHz(相对带宽为45.5%),轴向交叉极化大于33dB,频带宽,尺寸小,增益比较高,满足2G/3G/4G通信系统的需求。     

低轨卫星通信终端微带天线设计与实现

针对低轨卫星通信系统中微带天线的特性要求,首先利用高频结构仿真软件HFSS建立微带天线模型,并对该模型运用电磁理论和优化理论进行仿真优化,得到了最佳的微带天线结构和电参数.然后根据设计参数研制了符合要求的中心频率为398 MHz的微带天线,并且缩减尺寸至可以植入卫星通信中的便携式终端设备.利用矢量网络分析仪对该天线各参数实测结果表明,研制的微带天线的性能与实际要求的指标吻合,证明了设计的有效性.     

宽频带圆锥对数螺旋天线仿真计算与性能分析

介绍了一种用于宽脉冲电磁辐射的宽频带天线——圆锥对数螺旋天线。在通过近似解析计算进行天线结构粗略设计的基础上,利用仿真软件对其进行了较准确和全面的仿真计算,得到了天线的方向图、输入阻抗、电压驻波比和天线上的电流分布等各项参数,从而论证了原解析的误差范围和适用范围。     

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。     

TPMS倒F螺旋天线的设计与实现

在TPMS系统中,天线性能的好坏直接影响无线通信的效果.倒F螺旋天线具有全向性、增益高的特点.针对倒F螺旋全向天线进行研究与设计,用电磁仿真软件CST对天线模型进行了设计与仿真,并根据优化结果制作了实物模型.测试结果表明:谐振频率为433 MHz,回波损耗为-19.49 dB,测试结果与仿真结果吻合良好.     

A dual band dual antenna with read range enhancement for UHF RFID tags

This article presents a novel dual antenna structure for dual ultra high frequency bands (f₁ = 866 MHz and f₂ = 915 MHz) for radio frequency identification tags. The proposed structure consists of two dual band antennas, one acting as a receiving antenna and the other as a backscattering antenna at both the frequency bands. The receiving antenna is designed to have input impedance complex conjugate to the impedance of tag IC in order to maximize power transfer between the antenna and the microchip. The backscattered antenna is designed to have real‐valued input impedance at both the operating frequency bands to obtain maximum differential radar cross section leading to read range enhancement. The dual band receiving antenna is designed by embedding a pair of thin slits at a radiating edge of inset fed microstrip antenna. The backscattering antenna is comprised of two elements, one is a comb‐shaped open ring element, and the other is a meander line structure which is within the open ring element. Compared to conventional antennas, the proposed dual antenna structure provides a read range enhancement due to improved maximum differential RCS. The proposed dual antenna produced 4.3 m and 6.8 m read range at 866 MHz and 915 MHz, respectively.     

RFID tag antenna for ultra and super high frequency band applications

A novel dual‐band antenna for radio frequency identification tag is proposed for ultra high frequency (UHF: 915 MHz) and super high frequency (SHF: 2450 MHz) bands. The proposed tag antenna is a single sided dual‐antenna structure, designed on the grounded (metallic) dielectric substrate. The proposed tag antenna can be used on any kind of surfaces including metals without severe performance degradation due to its metallic ground plane. At UHF band, proposed tag antenna works as dual‐antenna structure. In the dual‐antenna structure, one antenna works for receiving and another for backscattering. Due to separate backscatterer, the maximum differential radar cross section improved and results in the enhancement of the maximum read range. Whereas at SHF band, proposed antenna works as conventional single antenna structure and during operations it switches between receiving and backscattering modes. The proposed antenna consists of a meandered line antenna and a rectangular patch antenna loaded with an F‐shaped and an inverted L‐shaped slots. The S‐parameters are measured by means of differential probe technique. Simulated and measured results are observed in good agreement. The read range is observed about 5 and 6 m at 915 and 2450 MHz, respectively. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:640–650, 2016.     

Linearly tapered meander line cross dipole circularly polarized antenna for UHF RFID tag applications

In this article, a circularly polarized antenna for ultra‐high frequency radio frequency identification (RFID) tag is presented. The circular polarization is realized by two orthogonal, unequal length linearly tapered meander line cross dipoles. The meander structure with capacitive tip loading is used for size miniaturization of the antenna. A modified T‐match network is employed to feed the cross dipole structure. The measured 10‐dB return loss bandwidth of the cross dipole antenna is 17 MHz (908‐923 MHz) and the corresponding 3‐dB axial ratio bandwidth is 6 MHz (912‐918 MHz). The overall size of the proposed antenna is 0.17λ₀ × 0.17λ₀ at 915 MHz. The maximum read range between the reader and the tag with the proposed antenna is 4.7 m larger than the analogous linearly polarized tag antenna due to the reduction in polarization loss between the tag and reader antennas. Thus, a maximum read range of 15.66 m with the gain of 1.28 dBic is achieved at 915 MHz.     

Free space and user proximity analysis of octaband monopole MIMO/diversity antenna for modern handset applications

In this article, a comprehensive study of the compact octaband monopole MIMO/diversity antenna is carried out in the free space and user proximity. The radiating structure of the proposed antenna consists of a driven element which is directly fed with microstrip line and a parasitic element. However, the designed antenna provides of 730‐885 MHz at lower frequency side and 1670‐2740 MHz at higher frequency side. Further, to reduce the mutual coupling between two antenna elements, a folded T‐shaped structure is designed of electrical length λ/4 at 0.8 GHz and attached to the ground plane. This structure helps in isolation improvement up to the level of ?12 dB from ?6 dB. The folded structure of T‐shaped provides compactness to the proposed antenna. Thereafter, three kinds of user proximity named as Talk mode, Data mode, and Read mode along with mobile phone are studied. Moreover, the specific absorption rate (SAR) is calculated and found well below the standard limit of FCC and European standard. Finally, the proposed antenna is fabricated and tested. The measured results are in close agreement with simulated results.     

Gain and isolation enhancement of patch antenna using L‐slotted mushroom electromagnetic bandgap

In this paper, the application of the L‐slotted mushroom electromagnetic bandgap (LMEBG) structure to patch antenna and antenna array is investigated. A coaxial fed patch antenna and antenna array are designed at 5.8 GHz, center frequency for ISM band (5.725‐5.875 GHz). Two layers of LMEBG are placed around the patch to achieve a gain enhancement of 1.9 dB. Measured results show a bandwidth enhancement of 300 MHz with an additional resonant frequency at 5.6 GHz with 4.5 dB of gain. A 5 × 2 array of LMEBG is used to achieve a 2 dB mutual coupling reduction and 2 dB gain enhancement for a two‐element H‐coupled patch antenna array.     

应用于TPMS的PCB螺旋天线的设计与实现

针对TPMS中发射天线安装空间有限这一难点,提出了一种PCB螺旋天线.采用将螺旋天线加工于PCB上的结构,极大地减小了天线尺寸.设计出的天线具有良好的全向性,加入匹配网络后,在工作频率433.92 MHz处的回波损耗值约为-40dB,满足TPMS发射天线的性能要求.根据优化结果制作了该天线,测试结果与仿真结果基本吻合,实物尺寸为20 mm×16.7 mm×10 mm,实现了小型化.     

应用于平板电脑的4G-LTE/WWAN天线设计

随着3G网络的广泛建设以及LTE和WiMAX标准的兴起,移动通信系统正向着4G时代稳步迈进。文中提出了一种应用在平板电脑上多频段平面单极LTE/WWAN天线的设计方法,该天线结构由一个变形的L贴片和两个寄生短截线构成。天线的频段可覆盖整个LTE(LTE700/2300/2500)及五个WWAN(GSM850/900/1 800/1 900/UMTS)频段。其频率带宽可分为低频部分:700~960 MHz和高频部分:1 710~2 700 MHz,可在整个带宽内做到无缝衔接的宽带通信。该天线不仅可以实现宽频化,而且结构简单、尺寸小、易于集成。     

Design and development of enhanced bandwidth multi‐frequency slotted antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐band applications

A multi‐frequency rectangular slot antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐bands applications is presented. The proposed antenna is comprised of rectangular slot, a pair of E‐shaped stubs, and an inverted T‐shaped stub and excited using staircase feed line. These employed structures help to achieve multiband resonance at four different frequency bands. The proposed multiband slot antenna is simulated, fabricated and tested experimentally. The experimental results show that the antenna resonates at 2.24, 4.2, 5.25, and 9.3 GHz with impedance bandwidth of 640 MHz (2.17‐2.82 GHz) covering WiMAX (802.16e), Space to Earth communications, 4G‐LTE, IEEE 802.11b/g WLAN systems defined for S‐band applications. Also the proposed antenna exhibits bandwidth of 280 MHz (4.1‐4.38 GHz) for Aeronautical and Radio navigation applications, 80 MHz (4.2‐4.28 GHz) for uncoordinated indoor systems,1060 MHz (5.04‐6.1 GHz) for the IEEE 802.11a WLAN system defined for C‐band applications and 2380 MHz (7.9‐10.28 GHz) defined for X‐band applications. Further, the radiation patterns for the designed antenna are measured in anechoic chamber and are found to agree well with simulated results.     

Parasitic effects of the metallic towers on the characteristics of the broadcast antennas

In this article, we use a tool NEC (Numerical Electromagnetic Code) to model antenna on top of a tower structure. Simulation results for the parasitic effect of the tower on characteristics of broadcast DVB‐T (Digital Video Broadcasting Terrestrial) antenna such as input impedance, return loss, gain, front‐to‐back ratio and radiation patterns are reported. In addition, the effect of a nearby tower on antenna characteristics is studied. A 3D tower and broadband antenna in the UHF (470‐862) MHz band are constructed. The antenna works for both digital and analog TV with return loss (RL) ≥ 10 dB, fractional bandwidth of 87% and gain of 12.3 dBi at center frequency. The effective radiated power is calculated by mounting the antenna at each face of the tower to give a satisfactory coverage to a region around the antenna.