Novel radiation pattern reconfigurable antenna with six beam choices

This article presents a novel radiation pattern reconfigurable antenna with six beam choices,which works in 5.2 GHz wireless local area network (WLAN) frequency band.The designed antenna has good imped...     

A novel radiation pattern and frequency reconfigurable single turn square spiral microstrip antenna

This paper presents a novel pattern and frequency reconfigurable microstrip antenna that uses switched connections. The basic antenna operates with linear polarization around 3.7 GHz. One set of connections provides a re-directed radiation pattern while maintaining a common operating impedance bandwidth with the baseline configuration. The second set of connections results in operation at a higher frequency band at 6 GHz with broadside patterns. Measured results of the three antenna configurations are provided. Potential applications of this reconfigurability and directions for future work are discussed.     

一种基于超表面的方向图可重构天线

为了满足日益增长的对多功能天线的需求,提出了一种基于超表面覆层的低剖面可重构天线. 该天线由三部分组成:矩形蘑菇型超表面覆层,缝隙耦合天线和简单的直流偏置控制电路. 通过分别调整两组PIN开关的工作状态,使得天线辐射表面的电流被改变,进而实现辐射方向图的重构. 通过仿真计算和优化,最终确定了天线的最优结构. 实测结果表明:天线可以在四种不同的状态下工作,其xoz面方向图可以在±30°之间切换;四种工作状态的共享?10 dB阻抗带宽为4.2%. 所提出的天线具有低剖面、高增益、低成本、操作简便等特点.     

差分馈电双极化四波束方向图可重构天线

提出了一种平面差分馈电双极化四波束方向图可重构天线.该天线由两个相互正交的偶极子和四个带PIN二极管的寄生单元构成,有两个差分馈电端口,通过短截微带线给两个相互正交的偶极子馈电.两个偶极子正交摆放、异面垂直,与寄生单元蚀刻在同一基板上,整体结构简单.切换PIN二极管的不同状态得到四个波束的方向图可重构和两种方式的极化可...     

一种新型的宽带方向图可重构天线

本文介绍了一款新颖的PRA(Pattern Reconfigurable Antenna).天线辐射单元主要由三部分组成:包括矩形驱动贴片,两个对称的开了CRS(Cross Ring Slot)的半圆形寄生单元以及地平面.两组p-i-n二极管分别放置在十字形环缝隙上,通过这两组p-i-n二极管电开关将它们连接起来,从而可以实现辐射方向图可调.仿真结果表明,天线在4.29GHz~4.87GHz频率范围内S11<-10dB,阻抗带宽大于500MHz,具备良好的宽带特性.并且具有三种辐射方向图,可以通过p-i-n二极管电开关灵活控制,实现方向图可重构特性.     

带寄生贴片的圆盘形方向图可重构天线设计

提出了一种新的带寄生贴片的圆盘形方向图可重构天线。天线主要由位于中心的圆形贴片和周围环绕的五个带U型槽的扇环形寄生贴片组成。该天线工作在5.5 GHz WiMAX(全球微波接入互操作性)波段范围内,在谐振频率点具有较好的阻抗匹配特性。通过控制开关,天线可以在θ=45°的面内实现五种定向方向图变化。计入方向图增益及波瓣宽度,可以实现波束全向覆盖。天线方向图的旁瓣和后瓣较小,主瓣方向最大增益可达6.3 dB,定向辐射特性显著,具有较强的抗干扰能力。该天线尺寸小、剖面低。还分析了一些重要结构参量对天线性能的影响。天线的仿真与测试结果具有较好的一致性。     

Single feed antenna with radiation pattern diversity

A vehicle diversity antenna system comprising a single-fed element together with a loaded parasitic element is described. Different termination loads on the parasitic element give rise to variations in the radiation patterns that are comparable with a four-element diversity system. There was good agreement between measured parameters and simulations.     

基于MEMS开关的方向图可重构天线的设计

设计了一种波束可重构天线,以实现宽带、宽角方向图可重构设计。该天线由4组具有不同波束指向的天线子阵组成,通过6个RF-MEMS开关控制其波束指向;采用的宽带单元天线,在2.4 GHz～3.4 GHz频率范围内(相对带宽34.5%),电压驻波比小于2。馈电网络的设计采用小型化宽带阻抗变换器,减小了馈电网络尺寸,并拓展了带宽。仿真结果表明,可重构天线实现了0°,25°,40°和50°的不同波束指向,除部分频点外,4种状态天线的驻波在2.5 GHz～3.25 GHz(相对带宽26%)带宽内驻波比均小于2。     

Design of electrically small, pattern reconfigurable Yagi antenna

An electrically small, pattern reconfigurable Yagi antenna is designed fabricated and measured. Two directors are located on the two opposite sides of the driver. A pin diode is used on the bottom of the director to switch the beam pattern. The measured maximum realised gain of the antenna is 8.5 dB and the front-to-back ratio is 7 dB.     

Broadband RFID tag antenna with quasi-isotropic radiation pattern

A passive RFID tag antenna in the UHF band using two bent dipoles and a modified double T-matching network is proposed. The antenna was fabricated with a thin copper layer printed on a 50 /spl mu/m-thick PET substrate for low-cost production. The proposed antenna provided a quasi-isotropic radiation pattern and a fairly broad bandwidth S/sub 11/<-10 dB, 8.5%) for conjugate-matching with a commercial tag chip. The efficiency of the antenna was about 90% in the operating frequency band. The measured readable range was between 170 -240 cm for an arbitrary rotation angle of the tag.     

Ku band pattern reconfigurable substrate integrated waveguide leaky wave horn antenna

A dual band substrate integrated waveguide H plane sectoral horn antenna with reconfigurable radiation characteristics has been proposed in this paper. Designed antenna acts as a perfect broadside radiator at 16.1 GHz and perfect endfire radiator at 14.4 GHz frequency. Broadside radiation has been achieved by etching rectangular slots in the flared section of horn exhibiting a gain of 8.87 dBi. To achieve perfect endfire radiation, dielectric loading is done at the edge of horn and at this frequency antenna shows a gain of 11.3 dBi. The horn and the loaded dielectric are integrated by using the same single substrate resulting in easy fabrication and low cost. The proposed design has been fabricated and measured results are in good agreement with the simulated results.     

A novel miniature hexagonal shape switched pattern and frequency reconfigurable antenna

This proposed work introduces the structure of frequency and pattern reconfigurable patch antenna. This proposed design comprises of a hexagon patch antenna with four oblique slits, two longitudinal and two latitudinal slits. Four PIN diodes are used to enable frequency and pattern reconfiguration in the longitudinal and latitudinal slits. The operating frequencies of the proposed reconfigurable antenna are 4.25, 5.65, 6.8, and 8.2 GHz and have a pattern slope of ?30°, 0°, +30°, and 180°. The pattern is reconfigurable in four directions without any servo system. The designed antenna is fabricated, and its performance is proved using quantifications. Experimental results have less than 15% error with the simulated results. This antenna is used for C‐band applications.     

Frequency tunable monopole coupled loop antenna with broadside radiation pattern

A frequency tunable antenna made with an open-circuit monopole coupled loop antenna associated to a varactor diode is presented. The proposed antenna shows a 35.8% relative bandwidth, covering the 470?675 MHz frequency range. Theoretical and experimental results of S₁₁, radiation patterns and gain have been performed and show good agreement.     

Direction-of-arrival estimation using radiation power pattern with an ESPAR antenna

An approach for estimating direction-of-arrival (DoA) based on power output cross-correlation and antenna pattern diversity is proposed for a reactively steerable antenna. An "estimator condition" is proposed, from which the most appropriate pattern shape is derived. Computer simulations with directive beam patterns obtained from an electronically steerable parasitic array radiator antenna model are conducted to illustrate the theory and to inspect the method performance with respect to the "estimator condition". The simulation results confirm that a good estimation can be expected when suitable directive patterns are chosen. In addition, to verify performance, experiments on estimating DoA are conducted in an anechoic chamber for several angles of arrival and different scenarios of antenna adjustable reactance values. The results show that the proposed method can provide high-precision DoA estimation.     

频率可重构超宽带天线研究

超宽带天线和可重构天线是当今天线领域研究的热点。将可重构天线技术应用到超宽带天线设计中,讨论了频率可重构超宽带天线的设计思路。以印刷单极子椭圆天线为原型,给出了两个可重构天线的具体结构,并对天线进行了可重构带阻设计,避免与相关频段之间的干扰。仿真结果表明:重构后天线Ⅱ的低频获得了扩展,其相对尺寸的长和宽分别减小到最大工作波长的0.116倍和0.087倍,工作频段为0.174~10.9GHz,可重构阻带为5.1~5.95GHz,带宽比可高达62:1.     

Optoelectronically reconfigurable monopole antenna

A monopole antenna is reconfigured for 200 or 375 MHz bands by optoelectronically switching two segments together. Light levels of much less than 1 mW significantly change the antenna pattern and gain.<>     

A reconfigurable slot antenna with switchable polarization

A novel reconfigurable slot antenna architecture allowing polarization switching is presented. The antenna shape consists of a slot-ring with perturbations which are switched on and off using pin-diodes. Two antennas allowing switching either between linear and circular polarization or between two circular polarizations are demonstrated. The antenna architecture is interesting for commercial wireless applications because it is compatible with modern fabrication processes and can be realized on low cost dielectric materials.     

On the radiation pattern of a multibeam antenna

The optimum radiation of a lens antenna with an array feed ofMelements is desired, which will exhibit maximum gain in a number (k) of specified directions and nulls in other (j) specified directions. This optimum is not derived; however, a condition for the optimum is shown to be some superposition of just (k + j) individual radiation patterns where each individual pattern is obtained by a separate excitation set of allMfeed elements such that the gain is maximized in each of the (k + j) directions. (The feed array excitation set for each of the (k + j) maximum gain individual patterns is derived.) Thus the number of unknown feed excitation coefficients is reduced fromMto (k + j).     

频率方向图复合可重构寄生单极子天线阵列

提出了一种能应用于无线通讯系统的新型介质支撑开关寄生阵列天线。基于八木天线原理,天线可以实现频率及方向图的复合可重构。所引入的开关用来切换不同状态的工作频率并实现方向图的扫描。地支结构用来改善天线的阻抗匹配并展宽频带。测量结果表明：天线阵列可以在保证回波损耗小于-10 dB的情况下完全覆盖1710~1880 MHz、1850~1990 MHz及2400~2480 MHz三个移动通信频段,并可以方便地实现频率切换及方向图扫描。     

Wide tunable dual-band reconfigurable antenna

Presented is an antenna that allows independent and versatile dual frequency and bandwidth reconfiguration by using simple external matching circuits. Simulations suggest that the antenna has a total tuning range of 2118 MHz (from 778 to 2896 MHz) while maintaining a return loss above 6 dB. In addition, the antenna is capable of operating as a penta-band cellular phone antenna. This kind of antenna is typically required to work within the GSM900, GPS1575, GSM1800, PCS1900 and UMTS2100 bands.