具有三陷波特性的类Sierpinski分形超宽带天线

为避免窄带通信系统对超宽带(ultra-wideband,UWB)系统的干扰冲突,提出一款具有三陷波特性的类Sierpinski分形UWB天线.辐射贴片采用圆环与五角星形嵌套迭代的2阶类Sierpinski分形结构,并采用缺陷地结构接地板以实现良好的UWB特性.通过在分形结构的上部添加对称倒L形开路枝节,在微带馈线两侧添加对称L形开路枝节,并在馈线处刻蚀倒π形窄缝隙产生了4.5～4.8 GHz、7.2～7.8 GHz和8.0～8.5 GHz三个频段的陷波特性.仿真和实测结果表明,天线在3.1～18.1 GHz的频段内,可有效抑制国际卫星波段、X卫星波段和国际电信联盟波段等窄带系统的干扰.该天线除滤波频段内,在通带频段内有较稳定的增益和全向辐射特性,可用于各种UWB系统中.     

具有陷波特性的改进Sierpinski分形超宽带天线

为了避免WLAN窄带通信系统对超宽带通信系统的干扰,该文提出一种具有陷波特性的改进 分形超宽带天线。天线的辐射单元是改进的 阶 分形结构,通过采用共面波导馈电技术以及增加 分形的迭代次数,可有效展宽天线的带宽,从而实现覆盖 频段的宽频特性。在分形贴片上增加两个对称的L型开路枝节,实现了 频段的双陷波特性,能有效抑制WLAN频段对超宽带通信系统的干扰。天线的尺寸较小,仿真和实测结果表明天线可广泛适用于各种UWB通信系统。     

具有双陷波特性的蜂窝结构分形超宽带天线

提出了一款具有双陷波特性的蜂窝结构分形超宽带（ultra-wideband，UWB）天线，采用二阶蜂窝结构作为辐射贴片和缺陷地结构接地板实现良好的超宽带特性.通过在辐射贴片上挖去正六边形和矩形宽缝隙并引入对称鱼钩形枝节，在馈线处刻蚀倒U形窄缝隙产生了3.27~4.27 GHz和7.2~8 GHz两个频段的陷波特性.天线在2.8~11.6 GHz的频段内，可有效抑制WiMAX、C波段卫星和X波段卫星窄带系统的干扰.仿真和实测结果基本吻合，表明该天线适合应用于各种UWB通信系统.     

具有双陷波特性的六边形分形超宽带缝隙天线

提出一款具有双陷波特性的六边形分形超宽带缝隙天线,天线总尺寸为32 mmx16 mmx1.6 mm,采用六边形和三角形迭代嵌套的3阶分形结构作为辐射贴片,并采用缺陷地结构作为接地板,实现了3.0～ 15.26 GHz的超宽带带宽.在馈线两侧引入对称L形开路枝节,并在接地板上刻蚀U形窄缝隙产生了4.71～5.87 GHz...     

具有陷波特性的超宽带分形缝隙天线

结合超宽带缝隙天线和分形结构的优点,设计了一种具有陷波特性的超宽带分形缝隙天线.选择E形缝隙结构,并在缝隙下边缘采用树状分形,构造半波长谐振结构,实现了天线的陷波功能,有效地避免了超宽带频带范围内的系统干扰.给出了天线设计的总体思路,通过理论分析和仿真测试,对天线的阻抗特性、增益进行了研究.结果表明,该陷波天线的阻抗频带为3 GHz ～12 GHz,在5 GHz～6.25 GHz频带内具有陷波特性.同时,分形结构的引入极大地缩小了天线的尺寸.     

具有陷波特性的超宽带印刷天线设计

设计一种具有陷波特性的超宽带印刷天线,天线采用圆形金属贴片作为辐射单元,采用微带线进行馈电,通过在贴片上开四个对称T形槽来实现陷波功能。利用仿真软件HFSS10．0对其进行计算,对天线的阻抗特性、方向图和增益进行了研究。运算结果表明,该天线在2．26～4．94GHz和6～11．68GHz的工作频带范围内电压驻波比（VSWR）小于2;在4．94～6GHz的阻带范围内具有良好的陷波特性;在阻带中心频率（5．48GHz）处,电压驻波比高达40。     

基于SRR结构具有陷波特性的超宽带天线

在Yang X等人提出的SRR(Split Ring Resonator)天线结构基础上,在天线贴片上设计出一个U型槽,通过改变该U型槽缝隙宽度、长度等参数,以不断调整阻带中心频率及带宽,从而实现了一种具有陷波特性、能够屏蔽无线局域网(WLAN)信号干扰的超宽带天线.仿真及测试结果表明,改进前天线的工作频带为3～11 GHz(VSWR<2),无陷波特性;而改进后的天线在4.4～5.7 GHz频率范围内具有良好的频带抑制特性,增益值最低可达到-15 dB,并且在其它工作频段具有良好的辐射性能.     

一种具有三陷波特性的超宽带印刷天线设计

提出了一种新型的具有三陷波特性的超宽带印刷天线。大钱形的辐射贴片和共面波导传输线馈电,可以保证在相当宽的3个频带内具有良好的阻抗匹配。回波损耗S₁₁＜-10 dB的阻抗带宽是3.1~10.6 GHz,除了其中3.3~3.7 GHz 的WiMAX,5.15~5.825 GHz的WLAN和7.25~8.4 GHz的X波段下行频段3个陷波频段。这些陷波的频段可以通过在天线的辐射贴片上增加长条裂缝和U形缝隙实现。加工和测试结果表明,该天线具有很好的阻抗带宽和全向辐射方向图。     

具有双频陷波特性的超宽带印刷天线研究*

通过在超宽带印刷单极子天线上开设不同形状和尺寸的缝隙,设计了一种由共面波导馈电的,具有双频陷波特性的超宽带天线.并且通过对天线仿真结果的分析,总结出了缝隙结构参数对天线陷波特性的影响规律.仿真和实测结果表明,除陷波频带外,天线在3.1到10.6GHz频带上的VSWR小于2,在3.4-3.77GHz和4.91-5.87GHz频段上具有良好的陷波特性,较好地避免了系统与WiMAX及WLAN之间的干扰.在非陷波频段上天线具有较好的全向辐射特性.此外,通过对天线表面电流分布情况的详细分析,推导出了天线的等效电路结构.     

一种新型具有双陷波特性的超宽带天线设计

本文提出了一种新型紧凑的具有双陷波特性的印刷超宽带天线。天线采用微带传输线馈电,并通过圆形与矩形 的混合结构辐射单元和带有矩形开槽结构的地板来实现天线的超宽带特性,工作带宽覆盖UWB 频率范围。通过地板上 两个对称的J 形开槽和微带馈线两侧对称添加的线型结构单元来实现双陷波特性,两个陷波频段刚好覆盖了3.5GHz 的 WIMAX 频段标准和5.2/5.8GHz 的WLAN 频段标准。同时,该天线在工作频带范围内具有良好的辐射特性,符合超宽带 通信的使用标准。     

A new ultra-wideband fractal monopole antenna

The paper focuses on the peculiar dynamic behaviour of the recently developed 8 mm² TO-220-packaged, high-voltage, double-interdigitated (or rwo interdigi-tation levels—TIL) GTO thyristor. This novel power device was rated under both slightly and heavily inductive resistive loads, i.e. close to the real conditions encountered in practical power circuits employing GTO thyristors. Emphasis is laid on the ability of TIL GTOs to switch safely, with minimum power losses, a certain amount of anode current under high-voltage conditions and high commutation frequencies. The merits of TIL GTO thyristors are analysed in terms of their reliability and switching efficiency, which include the total power losses (conduction and switching losses), turn-on and turn-off gains and the switching speed. It is shown that thanks to their built-in self-protective features, these novel GTOs possess an enhanced current-handling capability at commutation frequencies up to 50kHz under extremely tough load conditions. The main implications of the results for power applications are outlined.     

Frequency notched ultra-wideband microstrip slot antenna with fractal tuning stub

A frequency notched ultra-wideband (UWB) microstrip slot antenna with a fractal tuning stub is proposed. The antenna is similar to a conventional microstrip slot antenna, and by introducing a fractal tuning stub, frequency notched function is achieved. The antenna was studied experimentally regarding impedance bandwidth, radiation patterns and gain. The operation bandwidth of the antenna is from 2.66 to 10.76 GHz, in which a frequency notched band from 4.95 to 5.85 GHz was achieved, along with good radiation performance over the entire frequency range.     

Compact printed ultra-wideband monopole antenna with dual band-notched characteristics

A compact printed ultra-wideband (UWB) monopole antenna with dual band-notched characteristics is presented. One complementary split-ring resonator (CSRR) is etched inside the patch of the monopole antenna to achieve dual notch frequency bands. A practical example for a UWB antenna (working from 2.90 to 12 GHz) is demonstrated, with one notch frequency band at 3.40-3.48 GHz and the other at 5.40-5.98 GHz. In addition, the effect of the dimensions of the CSRR on the dual notch frequency bands is also analysed.     

类Sierpinski分形天线的分析与设计

提出了一款应用于L波段的类Sierpinski分形圆极化微带天线。该天线采用类Sierpinski分形结构和π型枝节技术,延长表面辐射电流路径,降低天线的谐振频率,实现天线小型化。天线工作在1.48 GHz的中心频率下,具有良好的圆极化性能。通过仿真分析与模型优化,天线最终尺寸为56 mm×56 mm×1.6 mm,工作频率为1.46～1.50 GHz,天线的-10 dB阻抗相对带宽为2.7%,3 dB轴比相对带宽可达0.4%,最大增益可达1.9 dB。     

An antipodal Vivaldi antenna with band-notched characteristics for ultra-wideband applications

An antipodal Vivaldi antenna (AVA) with band-notched characteristics is proposed in this paper for ultra-wideband (UWB) applications. For UWB systems, there will be some interference from the narrow band systems. The proposed antenna adopts resonant parallel strip (RPS) to reject an unwanted narrow band. It is easy to tune the RPS to eliminate the interference band. To validate this approach, a printed AVA with RPS is simulated and fabricated. From 2 to 9 GHz, the proposed antenna shows a good result with approximate 2:1 VSWR, an average gain of 6.5 dB, and stable radiation patterns except the notched band. At the center frequency of the notched band, the measured results show that the VSWR is more than 8:1, the realized gain is less than −10 dB and a messy radiation pattern is achieved. The simulated and measured results are in good agreement.     

CPW-fed ultra-wideband antenna with compact size

A coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna with compact size is presented. The entire size of the antenna is as small as 30times13times1.6timesmm. The measured and simulated impedance bandwidth defined by voltage-standing wave ratios <2 is from 3.1 to more than 10.6 GHz. The proposed antenna exhibits a nearly omni-directional radiation pattern with very compact size, which is suitable for various portable UWB systems.     

Coupled-line-fed dual-notch ultra-wideband antenna

A coupled-line-fed ultra-wideband planar antenna with dual band-notched characteristics is proposed. Narrow frequency band notching at 3.5 and 5.5 GHz is achieved using bent resonators coupled to the main feedline. Moreover, the two notched bands can be controlled independently. The proposed antenna design is tested using two independent full-wave solvers.     

Compact band-notched ultra-wideband antenna

A novel band-notched ultra-wideband antenna having small dimensions (12.7 times 22 times 1.6 mm) is proposed. With the use of a modified ground plane, a microstrip feed with bevel, and parallel dual patches, the proposed antenna has very wide impedance bandwidth measured at 8.18 GHz (2.97 to 11.15 GHz, defined by 2:1 VSWR). By inserting slits in the ground plane, a band-notched frequency of 5.12 to 5.88 GHz is achieved. The transmission loss and group delay are measured and discussed.