应用于WiFi/WiMAX的三频超介质加载天线

以研究超介质结构在天线中的应用为目的,采用了超介质理论中的负折射率传输线(NRI-TL)加载技术,设计了一种三工作频段的单极子贴片天线.该单极子天线由不均匀弯折线构成,采用共面波导(CPW)馈电.在2.45 GHz和55 GHz附近弯折线与超介质结构可形成折合单极子辐射;在3.55 GHz附近超介质结构可改变天线表面电...     

梯形弯折线单极子天线的谐振特性

基于矩量法数值方法,研究了由梯形弯折线构成的单极子天线的谐振特性。着重于分析在天线高度和宽度都有明确尺寸要求条件下,天线输入参数与梯形弯折线弯折次数的关系以及与弯折角的关系。结果表明,弯折角的改变对天线谐振特性具有很强的调节作用,恰当地选择弯折角可以有效地改变天线的谐振频率与带宽,提高天线的辐射能力和匹配性能。     

应用于WLAN和WiMAX的双频带印刷天线设计

提出了一种新型的用于WLAN/WiMAX通信系统的双频带印刷单极天线。通过改进的叉子形的辐射贴片,使天线在2.4 GHz频带内谐振。同时,在介质基板背面的引入寄生辐射贴片,利用与正面的辐射贴片的耦合效应,使天线谐振在5 GHz频带内。最终使得天线可以覆盖2.4/5.2/5.8 GHz WLAN 和5.5 GHz WiMAX频带。对加工后的天线模型测试表明,天线在工作频带内具有较好的全向辐射特性和可观的增益。因此,该天线在无线多频带通信系统中具有广泛的应用前景。     

一种五陷波超宽带天线的设计

为了在所需的多个陷波频带中获得额外的谐振频率,设计了一种具有五陷波特性的超宽带单极子天线,天线包括蚀刻了两个不封闭口字型槽的秤砣形贴片、矩形微带馈电线、缺陷接地板和两个类U形谐振器.将两个类U形谐振器耦合在馈电线附近,与辐射贴片上蚀刻的两个槽及缺陷接地板共同实现五陷波特性.该天线工作带宽为3.01～12 GHz,有效滤除了WiMAX通信频段(3.73～3.89 GHz)、C频段卫星通信系统(4.25～4.9 GHz)、无线局域网通信频段(5.51～5.83 GHz)、INSAT(Indian National Satellite System)频段(6.77～7.32 GHz)和ITU 8GHz频段(8.13～8.38 GHz)的干扰,且天线在通带频段内五个陷波特性和方向性结果均吻合良好.     

一种应用于车载通信的多频段全向天线

文中设计了一种应用于车载通信的多频段全向天线。该天线由印制于FR4 介质基板正反两面的金 属贴片组成,通过在主辐射贴片上端加载弯折枝节、在侧边加载边缘谐振单元、在背面加载电耦合电感电容(ELC)谐 振单元实现了其多频段特性;在主辐射贴片上蚀刻C 形槽拓宽了天线的中频带宽;天线的尺寸为58 mm×42 mm× 1. 6 mm。测试结果表明:S11≤-10 dB 的阻抗带宽为0. 82~0. 96 GHz、1. 7~2. 69 GHz、3. 34~3. 66 GHz、4. 81~4. 97 GHz, 覆盖了2G、3G、4G、5G 等频段。该天线具有小尺寸、宽频带以及全向性好等优点,可以应用于车载通信或其它移动 通信场景。     

应用于WLAN的宽频带天线设计

为了设计出可以覆盖无线局域网WLAN的2.4GHz,5.2GHz,5.8GHz三个频带的天线,采用一种结构简单的宽带双频共面波导馈电的单极子天线。该天线由一个平面倒L形和一个倒U形贴片连接构成,实际加工制作了一个天线并且实测了S11参数,结果表明该天线具有两个独立的谐振模式,并且在应用范围内具有良好的阻抗匹配特性。     

一种宽带WLAN贴片天线

文中提出了一种单馈的宽带贴片天线应用于无线局域网络通信。该天线由方形贴片、电抗性阻抗表面以及电磁带隙结构组成。文中提出同时加载电抗性阻抗表面和电磁带隙结构能够实现小型化以及宽带化。电抗性阻抗表面作为接地平面能够降低天线的谐振频率。电磁带隙结构能够提高天线的阻抗带宽。测试结果表明所提出的WLAN贴片天线的相对带宽为22.3%(S₁₁=-10 dB),覆盖4.77～5.97 GHz,可以获得6.3～7.2 dBi增益。与现有宽带小型化天线相比,该天线在保证宽带小型化的前提下仍具有较高增益,且辐射性能具有较高的一致性,十分有利于其应用。该天线能够覆盖IEEE 802.11a标准所规定的5 GHz频段,能够实现无线局域网之间的高速数传。     

基于S-SCRLHs谐振器的四陷波特性超宽带天线设计

提出了一种基于双开口简化复合左右手(Splited Simplified Composite Right/Left-Handed,S-SCRLHs)谐振器的四陷波特性单极子天线。天线包括切割型圆形贴片、微带馈电线、带有梯形缺口的矩形地板和两个S-SCRLH谐振器,它具有四个谐振点,将S-SCRLHs谐振器耦合在新型单极子超宽带天线附近,实现四阻带功能。仿真和测量结果表明,该天线在超宽带范围内存在四个阻带,它们分别是3.6~3.8 GHz Wi Max band、4.5~4.9 GHz C band、5.6~6.0 GHz WLAN band、7.2~7.6 GHz X band。通过尺寸优化,最终尺寸定于25 mm×20 mm×1.6 mm,测量结果和仿真结果匹配较好。和其他天线相比,该天线具有尺寸小、多阻带、选择性好等特点。     

一种小型化双频天线的设计与分析

提出了一种小型化宽频带双频天线的设计。该天线由一个E形微带贴片和一个偶极子天线组合而成,产生高低2个频率,且低频段带宽可控。仿真的-10dB阻抗带宽分别为83MHz(2.4～2.485GHz)和812MHz(5.1～5.912GHz)。能够覆盖IEEE802.11b/g(2.4～2.483GHz)和IEEE802.11a(5.15～5.825GHz)工作频段,并对仿真结果进行了分析。同时给出的设计双频段宽带小型化天线的方法,可以对高低2个频段分开设计,对工程实践有一定的指导意义。     

弯折线偶极子天线谐振特性的研究

本文研究了由矩形弯折线构成的偶极子天线的谐振特性,分析了弯折线偶极子天线的弯折次数、矩形弯折的高度以及弯折角度等参数对天线谐振特性的影响。结果表明,弯折线偶极子天线的参数改变对天线谐振特性有较强的调节作用,适当的改变天线的参数可以获得较好的天线尺寸缩减特性,适合RFID标签天线的应用。     

Shortening ratios of modified dipole antennas

Two types of modified dipole antennas, zigzag and meander-line types, are analyzed and the shortening ratios are calculated. A zigzag dipole antenna with a wire length of 0.58 wavelengths has a shortening ratio of 24 percent with a resonant resistance of46 Omega. A meander-line dipole antenna with a wire length of 0.70 wavelengths has a shortening ratio of 30 percent with a resonant resistance of43 Omega. It is found that the radiation patterns of these two types of antennas are similar to the radiation pattern of a conventional half-wave linear dipole antenna.     

Internal quad-band printed antenna for PDA phone

A quad-band inverted-F antenna for PDA-phone applications is presented. The proposed antenna measures only 46 times 12 times 0.8 mm. It has an inverted-L element combined with a meander-line branch to excite two resonant modes. By using a matching element, the bandwidth can be broadened to cover GSM850/GSM900/DCS/PCS bands. Simulation was performed by HFSS to optimally design the antenna, and a practical structure was fabricated to verify the simulation results. The antenna parameters were measured and are presented to validate the proposed antenna.     

Radiation and scattering from a microstrip patch on a uniaxial substrate

The problem of a rectangular microstrip antenna printed on a uniaxially anisotropic substrate is treated. The effect of anisotropy on the resonant frequency and surface wave excitation of the antenna is considered, and the radar cross section (RCS) of the antenna is calculated. The RCS calculation includes the effect of the load impedance (antenna mode scattering). Results for the resonant frequency of a patch on a uniaxial substrate are compared with measurements, and the RCS of a patch on an isotropic substrate is compared with measurements. The derivation of the uniaxial Green's function in spectral form, the associated moment method analysis for the input impedance and scattering of the microstrip patch, and the expressions for the far-zone fields of a source on a uniaxial substrate are presented.     

Wideband small patch antenna

A small patch antenna fed by a coaxial probe with a wideband characteristic is presented. By employing dual shorting pins and cutting a slot in the patch, the size of the patch antenna is reduced while its impedance bandwidth is enhanced. The resonant frequency can be reduced by /spl sim/75% when compared with the resonance edge of a conventional patch antenna. The antenna has an impedance bandwidth of 21.5% (SWR<=2) and maximum gain of 2.2 dBi.     

弯折线天线原理、结构及其研究进展

弯折线技术作为一种减小天线尺寸和实现宽频带的有效手段,在现代天线设计中被广泛使用.根据不同的技术要求,研究者们提出了多种改进结构.文中介绍了6种具有代表性的弯折线天线结构,其中包括双弯折线天线、折叠式弯折线天线、立体式弯折线天线、渐变式弯折线天线、行波弯折线天线和弯折线缝隙天线.同时也对上述6种天线的工作原理以及研究进展进行了简要的阐述.     

A New Method for Measuring Dielectric Constant Using the Resonant Frequency of a Patch Antenna

An analytical expression is given for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of a patch antenna. Based on this result, a new method is developed for the measurement of the dielectric constant of a thin slab substrate. Basically, the test equipment consists of a rectangular microstrip antenna the patch of which is fed either by a microstrip line or coaxial line. From the measured resonance parameters of the rectangular patch antenna, the dielectric constant can be easily obtained. The measured values of the present method are in agreement with the precision standard cavity resonator method. Accuracy of the dielectric constant so obtained is satisfactory.     

Dual-resonance spiral-like shorted patch antenna

A simple dual-resonance printed antenna based on a spiral-like shorted patch configuration with an additional shorting pin to generate the second resonance is presented. The antenna allows for relatively independent control of the two resonant frequencies. The antenna resonance is at 1.55 and 2.5 GHz. The 10 dB return loss bandwidth is greater than 1.4% across each of the resonant frequencies.     

Approximate expression for the resonant frequency of a rectangular patch antenna

An approximate expression is derived for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of the antenna. Accuracy of the expression is established by comparing the theoretical results with available measured results.     

A 2.4-GHz printed meander-line antenna for USB WLAN with notebook-PC housing

A 2.4-GHz meander-line antenna printed on a USB-WLAN card is presented for WLAN applications. The HFSS 3-D EM simulator is employed for design simulation. The printed meander-line antenna is realized on a FR-4 PCB substrate. The measured VSWR is less than 2 from 2.4 to 2.5 GHz. Besides different orientations, the meander-line antenna printed on a simulated USB-WLAN card was attached to the side wall of a notebook-PC to investigate the PC housing effects on the antenna radiation patterns.