一种宽带高低仰角增益的卫星导航终端天线

研究了一种宽频带高低仰角增益的卫星导航终端天线。天线由两对交叉偶极子天线臂、馈电网络和栅栏状反射腔组成;两对交叉偶极子臂分别位于水平面上和垂直面上,形成对上半空间各仰角方向上增益的有效贡献;馈电网络实现交叉偶极子馈电相位相差90°,满足天线的圆极化辐射;栅栏状反射腔实现天线的定向辐射和辅助调整天线的带宽和低仰角增益。分析了典型参数变化对天线性能的影响,测试结果表明,天线|S11 |≤-10 dB 的阻抗带宽1.330~1.810 GHz、轴比小于3 dB 带宽为1.54~1.66 GHz 和在1.561 GHz、1.575 GHz、1.602 GHz 频点10°低仰角最大增益分别为0.35 dBi、0.21 dBi、0.1 dBi。该天线具有高低仰角增益,尺寸小,频带宽的特点。     

一种三频内置手机天线的设计与仿真

本文提出一种新型平面倒置F型三频手机天线(PIFA)。天线采取单馈点同轴馈电,上层辐射片开h形槽孔,应用时域有限差分法对天线进行设计和仿真,在GSM900MHz,DCS1800MHz和ISM2450MHz 3个频段的增益分别达到了0.1dBi,0.25dBi和0.4dBi,带宽分别达到了6.44%,6.67%和4.5%,表明该天线可在三个频段工作,满足了新一代无线通信系统对频段、带宽和增益的要求。     

一种新型VHF双频宽带高增益全向天线

提出了一种工作在VHF频段的双频宽带中馈垂直极化高增益全向天线.天线采用中馈套筒天线结构形式,在天线上、下辐射体中部分别串接一个高频倒相线圈,天线底部加同轴扼流圈的设计方案.该天线在30 MHz～110 MHz和176 MHz～300MHz频带内具有良好的辐射特性,水平面增益为2～6dBi.     

一种集总元件加载极端电小折叠单极子天线设计

针对无线通信等领域对电小天线的应用需求，设计了一种基于加载集总元件技术的极端电小折叠单极子天线结构。该天线在平面单极子天线的基础上，增加短路枝节拓展电流路径扩展带宽，采用集总元件加载技术，在辐射贴片上串联电阻元件增加输入电阻，并联电抗元件以改善输入电抗，实现了天线的极端电小特性。仿真表明，这种结构可以达到0.053λ×0.022λ×0.000 8λ(94 mm×40 mm×1.5 mm,λ为低频170 MHz处的波长)的极端电小尺寸，电压驻波比(Voltage Standing Wave Ratio, VSWR)在170～910 MHz时小于2,具有超宽带特性，并在工作频带内天线都具有良好的全向辐射特性。仿真分析了350 MHz、550 MHz、750 MHz三个频点处的方向图，且对应增益分别能达到-28.8 dBi、-16.7 dBi、-10.4 dBi。加工制作了该极端电小天线模型，实验测试验证了该天线的电小特性和超宽带特性，且方向图和增益测试结果均与仿真结果吻合良好。     

一种新的超低剖面数传电台天线

基于由低介电常数电介质组成的平行板电容加载,设计了一种新颖的数传电台天线,运用新型馈电结构和加载方式将天线的总高度限制在0.015λ0（460 MHz真空波长）以内,水平方向全向辐射,具有良好的应用前景。该天线工作频率为460 MHz,极化方式为垂直极化。电磁仿真结果表明,天线谐振频率处的反射系数在-20 dB以下,天线在水平方向上的增益均值高于1.5 dBi,在水平方向上全向辐射。该天线在工作频率上具有良好的辐射效果。     

具有高带外抑制特性的滤波器天线集成设计

利用滤波器综合设计方法设计了一款新型的具有高带外抑制性的微带滤波器天线。滤波器天线由五个开口谐振环、平行耦合线和倒L 天线组成。设计思路是使用倒L 天线代替滤波器的最后一个谐振器,然后利用平行耦合线等效为导纳变换器将谐振器与天线进行耦合,从而设计出既有滤波性能又有辐射性能的滤波器天线。滤波器天线采用交叉耦合结构,在带外有两个传输零点,大大提高了滤波器天线的带外抑制能力。滤波器天线经过仿真和测试,结果显示其反射系数S11 <-10 dB 的相对带宽为8%(2.37 ~2.57 GHz),带内增益约1.6 dBi,传输零点在带外50 MHz 处,增益下降到-25 dBi,带外整体下降到-20 dBi 以下,带外抑制特性显著。     

Ag圆锥天线阵列的太赫兹波受激辐射仿真研究

根据宽频带THz辐射天线的要求,设计了圆锥结构的微米量级金属Ag天线及其阵列。采用矩量法分析了天线电场积分方程的求解方法,并采用CST软件仿真了Ag圆锥天线阵列能辐射太赫兹波特性,理论分析和数值仿真结果表明,单根Ag微米圆锥天线能产生有效的宽带THz辐射,辐射增益可达22.7dBi。而其组成的纳米圆锥天线阵则可进一步改善辐射方向性,提高增益到42.5dBi。该结果将有助于指导太赫兹波辐射源的实验研究。     

一种双频宽带天线设计

文中给出了一种双频宽带平面天线设计。该天线由矩形加载单极子,倒L形加载单极子和匹配网络组成,频带覆盖30MHz-88MHz、107MHz-500MHz,带内驻波比〈3,增益分别〉-22dBi和-10dBi。该天线具有宽频带、小型化和低剖面等特点,可以用作机载天线使用。     

新型WLAN平面倒F双频天线的设计

提出了一种新型的应用于2.4/5GHz蓝牙和无线局域网的双频内置平面倒F天线。该天线结构紧凑,可以方便地植入无线通信设备中,有较强的实用性。通过加载F形槽和阶梯形槽使天线能够满足无线局域网中小型化双频天线的技术要求。天线在蓝牙频段阻抗带宽达到300MHz(2.21~2.51GHz),在无线局域网频段阻抗带宽达到1070MHz(4.95~6.02GHz),辐射方向图表明该天线全向性能较好,增益在3.1~6.7dBi范围内。     

一种新型三线式宽频带短波基站天线

提出了一种新型三线式宽频带短波基站天线的详细设计过程,对天线进行了仿真分析和实际测试,该天线在2 MHz~30 MHz频带范围内满足电压驻波比小于2.0,相对增益可达3 dBi~5 dBi,比普通宽带短波基站天线工作频带宽、辐射效率高。而且适应于不同用途,三线式短波基站天线具有平拉和倒‘V’两种架设方式。     

手持终端波束成形天线阵列的优化设计

设计了一款适用于移动手持终端的低剖面波束成形天线阵列。该天线阵列由八个结构相同的倒F天线组成,可以工作在GSM1900(1880~1920 MHz)、LTE2300(2300~2400 MHz)和LTE2500(2540~2620 MHz)三个频段。通过功率传输效率最大化理论,可以优化出该阵列在所需方向上的最佳激励。通过馈电电路板给8个天线单元提供优化的激励,可以将天线波束偏转到所需方向,并且保证天线在该方向上获得最大可能增益。天线阵列工作在2.45 GHz时,在x、y、z方向上的增益分别为7.80、6.03和7.20 dBi;相应地,在1.9 GHz时分别为6.67、5.27和6.05 dBi。     

Dual band microstrip patch antenna array loaded with split ring resonators and via holes

Reduction in antenna size by using multi-band radiators play a vital role in the miniaturization of present world wireless handheld devices, as dual band behaviour of the antennas result in the integration of more than one communication standard in a single system and thus, saving the installation space required for separate antennas. In this context, this communication presents a shorted-pin dual band metamaterial inspired microstrip patch antenna array. Under the unloaded conditions, the traditional patch antenna array resonates at 5.8 GHz with gain of 9.8 dBi and bandwidth of 540 MHz. However, when each patch of this traditional antenna array is loaded with split ring resonator (SRR) and a metallic via hole is introduced in the patch, the same antenna array produces an additional resonant frequency in IEEE 802.11b/g/n 2.45 GHz Wi-Fi band with bandwidth and gain of 290 MHz and 5.6 dBi, respectively, while the initial resonant frequency (i.e. 5.8 GHz) gets shifted to IEEE 802.11ac 5 GHz Wi-Fi band, providing the gain and bandwidth of 11.4 dBi and 510 MHz, respectively. The proposed antenna array has been fabricated, and the measured results are presented to validate the proposed array. Moreover, the equivalent circuit of the proposed antenna array has been designed and analyzed to validate the simulated, measured and theoretical results. Attainment of dual band characteristics by incorporating the metamaterial with single band traditional patch antenna array makes this structure novel, as this has been achieved without any extra hardware cost, size and loss of structural planarity. Also, both the frequency bands of this proposed metamaterial inspired antenna array possess considerable gain and bandwidth.     

Compact PIFA for 2.4/5 GHz dual ISM-band applications

A compact and novel modified planar inverted-F antenna (PIFA) for dual ISM-band application is proposed. The proposed antenna, including a small ground plane, occupies a volume of 20/spl times/23.7/spl times/0.8 mm/sup 3/ (FR-4). The impedance bandwidth with 10 dB return loss is about 150 MHz (2380-2530 MHz) for 2.4 GHz band and 1450 MHz (5130-6580 MHz) for 5 GHz band. The measured radiation patterns are approximately omnidirectional and yield a gain of 1.0 dBi at 2440 MHz and 3.98 dBi at 5600 MHz, respectively.     

带短路匹配枝节的微带全向天线设计与分析

提出微带全向天线天线,结合微带渐变结构和λg/4短路匹配枝节结构,从而改善了天线的阻抗匹配,降低了天线的电压驻波比,提高了天线的增益.天线实物采用7节微带单元级联,在2 400～2 483.5 MHz的频带范围内实测VSWR<1.35,天线实测平均增益为9 dBi.采用更多的微带单元级联,可提高天线增益,适用于移动通信...     

Low-profile ultra-wideband inverted-hat monopole antenna for 50 MHz?2 GHz operation

A compact low-profile UWB monopole antenna is proposed to operate from 50 MHz up to 2 GHz. The developed double-ellipse inverted-hat antenna (IHA) is 15 inches in aperture, 6 inches tall, and achieves 215 dBi gain at 75 MHz (when it is λ/10 in aperture size) in the presence of a finite 21 inch diameter ground plane, with the corresponding frequency being 50 MHz for an infinite ground plane. Calculated and measured gain data are given with reasonable agreement. The tripleellipse IHA is investigated to resolve impedance matching issues at higher frequencies. Gain performance against antenna height and aperture are also studied. The proposed antenna is especially suited for small unmanned aerial vehicles.     

Design of Implantable Rectangular Spiral Antenna for Wireless Biotelemetry in MICS Band

For this study, we designed an implantable rectangular spiral antenna for medical biotelemetry in the Medical Implant Communications Service band (402 MHz to 405 MHz). The designed antenna has a U‐shaped loop for impedance matching. The antenna impedance is easily adjusted by controlling the shape and length of the U‐shaped loop. Significant design parameters were studied to understand their effects on the antenna performance. To verify the potential of the antenna for the desired applications, we fabricated a prototype and measured its performance in terms of the resonant characteristics and gain radiation patterns of the antenna. In the testing phase, the prototype antenna was embedded in human skin tissue–emulating gel, which was developed to simulate a real operation environment. The measured resonant characteristics show good agreement with the simulations, and the ?10 dB frequency band is within the range of 398 MHz to 420 MHz. The antenna exhibits a maximum gain of ?22.26 dBi and an antenna efficiency of 0.215%.     

基于二元偶极子阵的边射端射可重构RFID阅读器天线设计

基于射频识别应用场景中存在的一些T型结构，如楼内、地下矿井等存在的一些T型通道，为做好这些场景中的信号覆盖，本文提出了一种新颖的边射端射可重构的RFID阅读器天线。天线由可重构的馈电网络和两个相距半波长的偶极子组成，天线边射和双向端射的可重构特性通过控制馈电网络中的开关状态实现。为了验证天线性能，对其进行了加工测试。测试结果表明，天线在边射和端射状态下的阻抗带宽和增益分别为2.7%(900～925 MHz),4.15 dBi和1.9%(905～923 MHz),2.10 dBi,与仿真结果基本一致。该天线具有结构简单、小型化、低剖面等优势，在射频识别系统中有一定的应用价值。     

Accordion shape monofilar axial mode helix for RFID reader

An accordion shape monofilar axial mode helical antenna designed by curving the helix along the axis is proposed. This antenna achieves a low-profile characteristic as the 10-turn helix's axial length is 0.354/spl lambda/. The impedance bandwidth (SWR<1.5) is 9% from the frequency of 880 to 963 MHz and the axial ratio bandwidth (AR<3 dB) is 6.5%. The measured gain is 10.2 dBi. This antenna operated at the centre frequency of 915 MHz and has a tilted radiation of 17/spl deg/ to the curving side.     

Dual Band Planar Spiral Feed Backed by a Stepped Ground Plane Cavity for Satellite Boresight Reference Antenna Applications

This paper presents development of a new planar spiral feed for a satellite boresight reference antenna, operating at two widely separated frequency bands (2200–2300 MHz and 8000–8400 MHz). A stepped ground plane cavity with different quarter wavelength distances is proposed to provide unidirectional patterns at these frequency bands. A back lobe suppression of around 12 dB in 2 GHz band and better than 15 dB in 8 GHz band with a measured on-axis axial ratio of less than 3 dB is achieved for the dual band planar spiral feed with stepped ground plane cavity configuration. A boresight reflector antenna employing this feed has measured beamwidths of 7 degrees and 1.8 degrees respectively and gain of 26 dBi and 36 dBi at 2250 MHz and 8200 MHz.