Slot-loaded bow-tie microstrip antenna for dual-frequency operation

By loading a pair of narrow slots close to the radiating edges of a bow-tie microstrip antenna, dual-frequency operation can be obtained using a single probe feed. Various frequency ratios, within the range 2.0-3.0, of the two operating frequencies can be obtained by varying the flare angle of the bow-tie patch. Details of the antenna design and experimental results are presented and discussed     

Coplanar waveguide-fed uniplanar bow-tie antenna

The design of coplanar waveguide (CPW)-fed bow-tie antenna for the 2.4-GHz ISM band is described. A coplanar waveguide-to-coplanar strips (CPW-to-CPS) balun is used to obtain the balanced feed line for the printed bow-tie. An analysis method based on the mixed potential integral equation method is used to characterize the input characteristics of the bow-tie antenna. The numerical results obtained are in good agreement with the experimental data. Through experiments with bow-tie antennas of various extended angles, the bow-tie antenna with a 90° extended angle exhibits the widest bandwidth in the desired frequency band which has a bandwidth of 17% for a VSWR <1.5:1     

Analysis and design of broadside-coupled striplines-fed bow-tieantennas

The design of a bow-tie antenna fed by broadside-coupled striplines (BCS) for the 2.4-GHz ISM band is described. The two fins of the bow tie are, respectively, on the two sides of the substrate. The feeding balanced lines adopted are the BCS. A quarter-wave transformer is used to transform the microstrip line input to the BCS feed. An analysis method based on the mixed-potential integral equation method is used to characterize the input characteristics of the bow-tie antenna. The numerical results obtained are in good agreement with the experimental data. Through experiments with bow-tie antennas of various extended angles, the bow-tie antenna with a 90° extended angle exhibits the widest bandwidth in the desired frequency band, which has a bandwidth of 19% for a VSWR<1.5:1     

一种基于环缝高次模的双频段大频差天线

提出了一种基于加载环缝高次模的新型双频段大频差天线,其具体结构为在蝶形天线两臂上对称地加载一对闭合圆环缝隙。常规的环缝加载方式为开口环缝加载,该加载方式环缝工作在基模;而本文提出的闭合环缝加载,可使环缝工作在高次模。加载环缝高次模的利用,可使天线在实现大频差的同时确保其在高频段的性能。所研制的天线可实现超过3∶1的大频差,仿真和实测结果表明:天线在两个频段都具有良好的性能。新型天线结构的研制成功丰富了多频天线的种类,为实现大频差天线提供了一种新的思路和方法。     

探地雷达超宽带背腔蝶形天线设计与实现

设计实现了一种中心频率为400 MHz的吸波材料填充式背腔蝶形天线,并将此天线应用于超宽带探地雷达系统,组装完成了一套400 MHz无线控制探地雷达系统样机。背腔式设计的探地雷达收发天线可以克服传统蝶形天线在H面全向辐射所带来的缺点,从而提高雷达系统的信噪比及收发天线之间的隔离度。对背腔蝶形天线的设计进行了规律性研究,总结了吸波材料填充式背腔蝶形天线系统在工程化实现时的设计经验。实际路测数据验证了所设计背腔天线在此套探地雷达系统中性能表现稳定良好。     

蝶形微带天线的谐振频率与双频设计

介绍了蝶形微带贴片天线的一种双频设计。基于变分法导出蝶形微带天线谐振频率闭式计算公式，采用矩量法对天线进行了全波分析，该法比已有方法具有更广的适用范围。最后对设计结果进行了加工和测试，测试结果与实验结果相当吻合，证实了数值分析与设计方法的有效性。     

双极变张角时域天线设计

传统的超宽带天线概念是在频域下定义的,有些不能作为时域脉冲天线使用。为实现时域天线的定向性、低剖面、小尺寸、可承受高功率等性能,结合领结天线的低剖面特性和TEM喇叭天线的定向辐射特性设计双极变张角时域天线,该天线是根据光导开关的时域响应设计天线激励源的低剖面定向时域超宽带天线,仿真结果表明．该天线是一种高性能的时域天线。     

便携设备中带陷蝶形UWB天线的设计

提出了一种应用于便携设备中具有带陷特性的平面蝶形UWB天线.该天线采用蝶形贴片作为辐射单元,并由渐变线作为阻抗变换器与50 Ω馈线进行匹配.通过在辐射面上挖C形槽实现带陷功能,并给出仿真和实测结果.该天线的工作频带覆盖3.1～10.6 GHz,并有效避免了5.15～5.825 GHz的无线局域网(WLAN)频段,适于便...     

Experimental Confirmation of Design Techniques for Effective Bow-Tie Antenna Lengths at THz Frequencies

We present on the relationship between the bow-tie antenna length and its THz spectral emission response. Three well-known approaches for predicting accurate antenna length for a given central frequency were utilized and their validity was experimentally tested. It is shown that the simple quasi-static approach compare to other approximations is valid for frequencies up to ~1.5 THz. The bow-tie THz photoconcudtive (PC) emitter designed using this approximation exhibits THz radiation having the most accurate central frequency compared to the design frequency. Interestingly, the THz PC emitter utilized from this design technique also possesses the optimum radiation bandwidth.     

GA design of a thin-wire bow-tie antenna for GPR applications

A microgenetic algorithm has been applied to design a new ultrawideband thin-wire bow-tie antenna for ground-penetrating radar applications. The broadband performance of the antenna is achieved by resistive loading and by optimizing the number of wires and the angular distances between those wires. The radiation characteristics of the optimized antenna are discussed, and its performance is compared to that of a resistively loaded Wu-King dipole.     

Modeling of a quasi-optical Josephson oscillator

The authors have developed a computer model of a Josephson tunnel junction embedded in a general circuit with frequency-dependent impedance using the harmonic balance method. This model has been applied to the analysis of a two-dimensional Josephson junction array with integrated coupling structures, called a quasi-optical Josephson oscillator. Simulations are done for a junction with dipole, slotline, and bow-tie antennas. The results show that the junction with a bow-tie antenna gives the best performance, and the output power from an array of 4000 junctions can reach 25.7 μW at a frequency as high as 1091 GHz for niobium junctions deposited on a 0.207-mm-thick quartz substrate     

一种基于AFSS的可重构天线设计

针对5G智能天线双频工作,提出一种基于有源频率选择表面（active frequency selective surface, AFSS）的可重构天线,该天线由蝶形频率可重构馈源和八棱柱形AFSS构成,馈源采用的是共面波导方式馈电的蝶形单极子. AFSS由对称弯钩状缝隙的周期结构构成,通过PIN二极管进行加载,使得AFSS能够在3.4～3.6 GHz和4.8～5.0 GHz两个5G频段互为反射模式和透射模式. 利用AFSS对馈源天线激励的电磁波进行空间调控,可实现两个频段的全向和定向波束的切换,也可实现水平面波束扫描. 根据仿真设计的天线模型进行设计加工和实际测试,结果表明:该天线的工作频段可以覆盖以上两个频段,低频定向波束增益为7.6 dBi,高频定向波束增益为8.6 dBi;并且能实现高/低频双波段切换、全向/定向波束切换和水平面内360°波束扫描功能. 该天线具有波束切换灵活、功耗低、造价低等特点,在新一代无线通信系统中具有一定的应用价值.     

一种基于新型组合加载方式的大频差三频段蝶形天线

将分形技术和槽加载技术相结合,文中提出了一种基于新型组合加载方式的大频差三频段蝶形天线,其加载方式为开口圆环缝隙和寄生分形多三角形结构(TSFPE)的组合加载。新型天线可同时工作于X/ Ku/ Ka 三个频段,其中,蝶形天线两三角形臂控制X 频段,加载于三角形臂上的开口圆环缝隙和位于蝶形天线三角形臂顶点位置附近的TSFPE 分别控制Ku 和Ka 频段。新型组合加载方式充分合理地利用了天线各部分的空间,减小了各频段之间的互相影响,确保了每个频段的性能。验证了新型组合加载方式的可行性,丰富了多频天线的结构形式和种类。     

Measurement and analysis of miniature multilayer patch antenna

Although the microstrip patch antenna has a number of advantages such as low-cost and light weight, its physical size is quite large at low microwave frequencies. The designs of multilayer miniature patch antennas with coaxial feed are presented. The first design is a rectangular two-layer patch antenna. Measured results and the results of a preliminary analysis are presented. The projection area of the two-layer patch antenna is kept the same as the single-layer rectangular patch antenna. The resonant frequency of the two-layer antenna is reduced by 50% and has bandwidth of 5%, which is wider than the single-layer rectangular patch antenna. In the second design, the upper patch is cut into a bow-tie shape. This results in a 60% reduction in resonant frequency and a 12% bandwidth. Both the two-layer rectangular and the two-layer bow-tie antennas have good radiation patterns, with cross-polarization level lower than the copolarization level by more than 20 dB     

Electromagnetic modes in conical transmission lines withapplication to the linearly tapered slot antenna

A transmission line analysis of the bow-tie antenna and the linearly tapered slot antenna (LTSA) is presented. These structures belong to the class of conical transmission lines defined here in terms of conical coordinates. A complete set of solutions of the Helmholtz equation is obtained exhibiting TE and TM modes. Modal fields are expressed by Lame (1837) and Bessel-Schelkunoff functions. TE and TM eigenmode analysis is particularized to the bow-tie structure. Bow-tie antenna and LTSA are shown to be dual conical transmission lines by the image method and Babinet's principle. The modes of LTSA are calculated on the basis of the results obtained for the bow-tie structure. The radiation pattern of the LTSA is computed as the integral of a closed-form expression of the dyadic Green's function weighted by the modal electric field distribution over the slot aperture. The obtained dominant mode radiation patterns are validated by measurements from the literature. The radiation patterns of the first two-order modes are calculated and compared     

A Wideband Slotted Bow-Tie Antenna With Reconfigurable CPW-to-Slotline Transition for Pattern Diversity

We propose a slotted bow-tie antenna with pattern reconfigurability. The antenna consists of a coplanar waveguide (CPW) input, a pair of reconfigurable CPW-to-slotline transitions, a pair of Vivaldi-shaped radiating tapered slots, and four PIN diodes for reconfigurability. With suitable arrangement of the bias network, the proposed antenna demonstrates reconfigurable radiation patterns in the frequency range from 3.5 to 6.5 GHz in three states: a broadside radiation with fairly omnidirectional pattern and two end-fire radiations whose main beams are directed to exactly opposite directions. The proposed antenna is investigated comprehensively with the help of the radiation patterns in the two principal cuts and also the antenna gain responses versus frequencies. The simulation and measurement results reveal fairly good agreement and hence sustain the reconfigurability of the proposed design.     

Reflection coefficient optimisation at feed of parabolic antenna fitted with vertex plate

An expression giving the reflection coefficient at the feed of a parabolic antenna fitted with a vertex plate is minimised. The parameters open to optimisation are the vertex plate radius and its distance from the centre of the antenna. Graphs of the reflection coefficient as a function of frequency for some optimisation frequencies are given and compared with the corresponding graphs obtained from another method and from the case where the vertex plate is missing.     

低雷达散射截面的微带仿生天线

针对微带天线辐射性能提高和雷达散射截面(RCS)减缩这一矛盾,文中将仿生学原理应用到微带天线结构设计中,并提出一种蝴蝶仿生结构的微带天线。该结构在贴片蝶形化的基础上,将蝴蝶在阳光下呈现的深色区域通过开槽方式除去。理论分析和仿真、实测结果表明,该方法设计的微带天线在辐射性能没有变化的同时,在4 GHz～8 GHz频率范围内单站RCS有了较大幅度的减缩,最大减缩量达到了23 dBsm。     

Numerical and experimental analysis of circular-end wire bow-tie antennas over a lossy ground

This paper presents a numerical and experimental analysis of a wire bow-tie antenna situated horizontally near a lossy ground. The antenna is basically an array of identical wire dipoles having a common feed point and equal angular separation between two neighboring wires. This antenna is particularly suitable for ultrawide-band applications as it possesses a wideband property and allows a simple realization of resistive loading. It also provides a possibility to easily vary the antenna flare angle for the purpose of antenna matching or to adjust its footprint. In this work a theoretical model of the antenna is developed and verified experimentally. The wires are modeled as a tape-like structure by triangular patches and the antenna is analyzed using a mixed-potential integral equation formulation. Moreover, time-domain solutions are computed using the Fourier transformation, and a time-window technique is employed to calculate the antenna characteristic impedance. Using the model a comprehensive analysis of the antenna performance is carried out.     

模拟分析具有表面等离子体效应的纳米光学天线及其阵列

基于时域有限差分方法,模拟分析了位于介质材料上的杆形和蝴蝶结形两种金纳米天线及杆形天线阵列.结果表明天线近场光斑直径约可以达到波长的1/11,蝴蝶结形天线的光斑强度可以比入射光场增强91倍.杆形天线阵列仍可以实现这种增强效应.蝴蝶结形天线中光场增强最高可以达到28000倍,而且局域化的光场町以耦合到天线臂上的纳米颗粒.