双环电视发射天线制作

笔者在《电子制作》杂志上发表关于电视发射机制作方面的文章后,收到许多读者来信,要求介绍电视发射天线的制作方法。电视发射天线有很多种,其中双环电视天线频带宽、馈电简单、发射效率高而优于其它发射天线。其结构如图1所示,由上下环形振子,双导线以及支架等组成。上下环形振子的圆周长等于所发射电视频道的中心波长。双导线长度为所发射电视频道中心的0.3-0.5     

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...     

一种宽频带复合天线设计

针对多系统载体天线数量多的问题,提出了一种基于印刷振子结构的宽频带共口径复合天线设计方法;通过两种不同形式的印刷偶极子进行共口径设计：采用平面印刷偶极子结构完成宽带高增益线极化天线,通过宽带定向耦合器实现了天线和差方向图辐射;采用十字印刷偶极子实现低增益天线的圆极化辐射;两种天线单元印刷在同一微波介质上,通过优化天线单元布局,相对位置关系和增加金属隔离环等措施,降低天线之间的相互影响,实现共口径复合天线性能满足工程应用要求;加工了天线样机,测试结果表明线极化天线在工作频带1.2～1.8 GHz范围内和差通道电压驻波比小于1.8,和通道增益大于13.5 dBi,方位差波束零值深度小于-25 dB,圆极化天线在工作频带1.2～1.8 GHz范围内电压驻波比小于1.6,增益大于6.5 dBi,轴比小于2.5 dB,与计算结果基本一致;复合天线可以满足多种无线通信系统的需求,减少了天线数量,有效节省载体平台空间,同时具有结构简单紧凑、剖面低、易于工程实现等特点,具有广阔的应用前景。     

一种宽频带单臂螺旋天线的设计

设计一种带反射腔的宽频带单臂螺旋天线,在反射系数S11<-10 dB标准下,频带范围为0.686GHz-3.15 GHz,天线结构尺寸为半径59.5 mm,厚度3.2 mm。相比于传统的平面螺旋天线,该天线结构紧凑、不需要巴伦、加工制作简单方便,适合于有宽频带圆极化应用需求的电子设备。     

一种新型套筒天线宽频特性的HFSS仿真分析

针对传统套简单极子天线结构变量复杂、要做到3:1的频带宽度难的问题,利用电抗补偿方法设计了一款位于特殊接地铜管上的双层套筒偶极子天线,并利用HFSS软件对结构进行仿真分析,找到影响频带及反射特性的结构参数,通过软件自带的优化功能,对各个参数进行仿真优化,得到工作在800-960MHz,1710-1920MHz,2400-2483MHz频带范围内驻波系数低于1.5的实用套筒天线结构,包含目前移动通信所用频带:2G、3G和WLAN.天线在同一个结构上实现多频工作,且在各个频段内反射很小,节省了天线资源,利于系统集成.     

一种紧凑型宽频带圆极化射频识别天线设计

针对现有圆极化天线难以同时满足宽频带和小型化应用需求的问题,面向全球超高频射频识别(RFID)读写应用,采用新型功分移相馈电网络、旋转短路辐射贴片和耦合贴片、馈电探针和短路探针,设计了一种紧凑型宽频带圆极化射频识别天线。测试结果表明,该天线回波损耗大于15dB的相对带宽为59%,轴比小于3dB的相对带宽为34%,在全球超高频RFID频段范围内,天线辐射增益大于2.7dBi,辐射方向十分对称和稳定,其半功率波束宽度大于101°,适用于宽角度范围读写;与现有圆极化天线的性能指标和结构相比,该天线的工作频段不仅能够覆盖全球超高频RFID频段,而且结构紧凑,有利于RFID系统的低成本设计和实施。     

小型化中波发射天线技术探讨

近些年来,我国电子通信技术和经济不断发展,信息化、数字化、固态化等相关技术也在我国中波发射领域得到广泛的应用和普及,这不仅仅促进了我国中波广播设备和技术的进一步改革和进步,也促使了中波发射事业进入了新的时代。中波发射天线作为我国广播发射信号的重要载体,它的进步发展也带动了我国广播事业的发展,我国改革开放以来广播行业发展翻天覆地和快速更新换代就是极好的明证。由于中波发射天线结构和发信功率要求较大,同时也受到中波波长的限制,因此中波通信发展也受到一定的制约,对此本文笔者就小型化中波发射天线技术进行研究和探讨,着重对其功率容量、辐射频率以及频带宽度进行分析,希望起到抛砖引玉之效。     

广播电视发射天线技术及应用分析

随着我国广播电视事业的不断发展,研究其发射天线技术及应用凸显出重要意义。本文首先对广播天线做了概括,分析了目前广播电视发射天线的情况,研究了广播电视的发射天线技术,最后结合实践探讨了广播电视发射天线的技术特点以及要求。     

一种高增益宽频带圆极化微带阵列天线的研制

针对微带天线阻抗匹配带宽一般较窄的自身缺陷,基于相控阵雷达天线的应用背景,设计了一种工作在X波段的双层圆极化微带天线结构,且优化发现,其各电磁参数良好。为提高其增益,还在此基础上设计并最终制作了双层2×2结构的微带天线阵列,其实测性能与设计值相符,增益达到10.7dB,带宽1.2GHz,相应轴比为4dB,符合圆极化要求。     

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。     

Metasurface cavity antenna for broadband high‐gain circularly polarized radiation

The article presents a microstrip patch (MSA) fed high gain circularly polarized metasurface cavity (CP‐MSC) antenna using a planar progressively‐phased‐reflector and a transmissive linear to circular polarization conversion metascreen. The bottom metasurface reflector consists of a remodeled Jerusalem cross to obtain 2π reflection phase variation. Linear to circular polarization conversion is achieved by a hexagonal ring based meta‐element with high transmission and bellow 3 dB axial ratio from 9.5 to 10.5 GHz. Simulated and measured results of assembled CP‐MSC antenna with MSA are in good agreement. The gain of the proposed cavity antenna with 10 and 10.5 GHz MSA are 14.9 and 16.3 dBi, respectively. Below 3 dB AR throughout the operating band denotes significant circular polarization performance of the proposed antenna.     

基于感应耦合的UHF宽频带电子标签设计

采用感应耦合技术设计并制作了一款UHF电子标签天线,为了实现与标签芯片的阻抗匹配,耦合单元采用非均匀弯折技术。仿真结果表明,带宽(VSWR<1.2)为0.82 GHz～1 GHz,完全覆盖了UHF(0.84GHz～0.96GHz)全频段,且S_(11)<-22dB,具有较好的谐振深度。通过HFSS建模仿真分析发现感应单元距馈电单元的距离和馈电单元的形状对天线性能影响与理论分析基本吻合,对寄生耦合加载技术具有指导意义。     

Design and optimization of a modified Sierpinski fractal antenna for broadband applications

Immense understanding of antenna designers illustrate that a general microstrip antenna demonstrate low efficiency. Various techniques have been adopted to improve the performance characteristics of microstrip antenna. This paper deals with the optimization of Sierpinski fractal antenna structure by utilizing the particle swarm optimization (PSO) and curve fitting method. The required data for optimization and fitting the curve has been obtained by varying different design parameters of the proposed antenna. Electromagnetic solver Ansoft HFSS 13.0 is used for generating the parametric data. The MATLAB curve fitting tool is referred for developing the equations which exhibits the relations between the parameters of proposed antenna design. Particle swarm optimization technique is then applied to find the optimum values of the design parameters for the bandwidth enhancement of proposed antenna. Curve fitting based optimized design represents the remarkable improvement in the bandwidth of conventional microstrip line fed Sierpinski fractal antenna for broadband applications.     

Design of a dual‐polarized omnidirectional antenna for broadband applications

A broadband dual‐polarized omnidirectional antenna is presented. The proposed antenna consists of two parts, an asymmetric biconical antenna and a cylindrical multilayer polarizer. To have an almost perfect omnidirectional radiation pattern in the horizontal plane and the main radiating beam position at around , in the elevation plane, the asymmetric biconical antenna is used. Moreover, to provide dual polarization performance over the 2–18 GHz operational bandwidth, a multilayer polarizer is designed and optimized. Numerous simulations via Ansoft HFSS and CST microwave Studio CAD tools have been made to optimize the radiation pattern, gain, polarization, and the reflection coefficient of the antenna. Simulation results show that the radiation characteristics of the proposed antenna are extremely sensitive to the configuration and dimensional parameters of the multilayer polarizer. The designed antenna was fabricated with high mechanical accuracy and measured. Satisfactory agreement of computer simulations and experimental results was obtained. The main feature that distinguishes this antenna from the previous designs is the ability to provide the omnidirectional radiation pattern with small ripples, dual polarizations performance, and the wide bandwidth simultaneously. Based on these characteristics, the proposed antenna can be useful for broadband communication applications. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:591–600, 2015.     

一种宽频带双圆极化微带天线阵列设计

为支撑海量数据传输与宽带无线通信系统需求,提出了一款宽频带双圆极化微带天线。采用微带天线作为基本辐射单元,基于层叠寄生贴片方式与加载空气腔方法展宽天线工作带宽并提高增益值,利用电容加载的三分支线定向耦合器对天线单元进行馈电进一步展宽天线带宽,并实现双圆极化辐射特性。单元电性能仿真结果良好,阻抗与轴比相对带宽达27.9%,峰值增益达到5.6dBi。基于辐射单元进行4×4阵列组合,所设计阵列天线阻抗带宽覆盖7.2 ~ 9.4 GHz,同一单元不同极化与不同单元间端口间隔离度均 ≥ 15 dB,轴比在通带内均 ≤ 3 dB,方向图仿真与测试结果吻合良好,验证了设计方案的正确性。     

CPW‐fed C‐shaped slot antenna for broadband circularly polarized radiation

A novel broadband circularly polarized (CP) C‐shaped slot antenna fed by a coplanar waveguide is presented. The broadband CP operation can be achieved simply using a C‐shaped slot in the ground to produce orthogonal surface currents for left‐hand circular polarization. Using the semicircle‐shaped radiator patch, wide impedance bandwidth and broad axial‐ratio (AR) bandwidth can be obtained simultaneously. The measured results show that the proposed antenna can provide a 10‐dB impedance bandwidth of 105% from 2.78 to 8.92 GHz, and a 3‐dB AR bandwidth of 70.4% from 2.9 to 6.05 GHz. Finally, an antenna prototype with a reflector for unidirectional pattern applications is also developed. The proposed antenna has broader impedance and CP bandwidths but with a more compact size compared with the previous designs. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:739–746, 2015.     

Design and simulation of MEMS-based broadband unidirectional CPW-fed rectangular slot antenna

A broadband unidirectional coplanar waveguide (CPW) fed rectangular slot millimeter wave antenna based on micro-electro-mechanical systems (MEMS) non-silicon micro-fabrication technology is discussed. A wide impedance bandwidth of 75% (S₁₁ < −10 dB) was obtained. By adding three layers of wave cut-off slots and a guiding slot, the antenna achieves unidirectional radiation, and the max gain of the antenna increases from 3.8 to 6.8 dB. Ansoft HFSS and CST Microwave Studio, two high frequency structure simulation softwares based on finite element method (FEM) and finite integration method (FIM), respectively, are used to simulate and analyze the antenna performances.     

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.     

A novel broadband magnetoelectric antenna

A broadband antenna based on magnetoelectric dipole is proposed. The proposed antenna is composed of a bowtie‐shaped electric dipole and an elliptical ring antenna that works as a magnetic dipole. For a broadband performance, a microstrip‐to‐coplanar stripline transition balun is used to excite the antenna. All of them are printed on the same plane perpendicular to the ground. To validate the design, prototypes of the proposed antenna have been fabricated and measured. The measurement results show that the antenna has a wide impedance bandwidth of 66.7% (2.45–4.90 GHz) for voltage standing wave ratio (VSWR) less than 2 and a gain of 6.0–7.3 dBi over the operating frequency band. Meanwhile a high front‐to back ratio better than 16 dB over the operating frequency is achieved. The agreements between the simulation and measurement results indicate that the proposed antenna is suitable for wireless communication systems and phased array systems. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:213–218, 2015.