Very ultra-wideband printed CPW-fed slot antenna

A very ultra-wideband compact microstrip slot antenna targeting the 3.1-10.6-GHz frequency band is presented. The proposed antenna is a simple printed slot antenna with a novel radiator, which is fed by a 50 Omega CPW line. The measured return loss extends from 2.8-33.4-GHz, about 169-. The proposed antenna has a compact size of 24-25-mm. The measured radiation patterns confirm that the antenna shows an approximately omnidirectional radiation pattern.     

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.     

CPW-fed right-angled dual tapered notch antenna for ultra-wideband communication

A CPW-fed right-angled dual tapered notch antenna for ultra-wideband (UWB) communication is presented. The antenna has two tapered notches, which are located at a right-angled corner. The measured gain pattern shows that two main beams are equally generated with approximately 7 dBi at 5 GHz. The performance of the antenna has been tested in a UWB communication experiment.     

共面波导馈电的频率可重构印刷单极子天线

提出了一种间接改变天线辐射体长度的方法。该方法通过改变天线馈线中地导体的长度,间接地改变天线辐射体的长度,有效避免了有源开关对天线辐射性能的影响。为验证此方法,设计了一个共面波导馈电的频率可重构印刷单极子天线,该天线利用PIN二极管来改变馈电端地的长度。实验结果表明:控制开关的工作状态,可使天线的谐振频率发生明显的变化。相应的中心频率分别为1.9 GHz和2.3 GHz,相对阻抗带宽分别为20.8%和17.2%。     

Planar elliptical antenna for ultra-wideband communications

A printed planar elliptic patch, juxtaposed with the ground pattern in a single substrate, providing an ultra-wideband impedance bandwidth, is presented. The ultra-wideband property for the proposed antenna is achieved by using a new impedance-matching technique of cutting a notch in the ground pattern opposite the microstrip line. The concavity of the ground pattern serves as an effective means of adjusting the gap between the radiating element and the ground plane. With suitable size of notch chosen, the impedance bandwidth of the proposed antenna can be enhanced. Details of the proposed antenna design and measured results are presented and discussed.     

Compact wide-slot antenna for ultra-wideband communications

A novel microstrip-line-fed wide-slot antenna is proposed. Investigations on the prototype of the bevelling square slot design with a small tail slot were employed to increase the wide impedance bandwidth range. The proposed antenna has a simple, symmetric structure and compact size. The matching impedance below 2:1 VSWR is applicable to ultra-wideband communications (3.1-10.6-GHz) with proper choices of bevel of the slot and the size of the tail slot cut in the ground plane.     

Broadband printed CPW-fed circular slot antenna

A broadband printed CPW-fed circular slot antenna is proposed. This antenna is composed of a circular slot fed with a 50 /spl Omega/ CPW line through a circular patch. A parametric study was carried out to optimise the proposed structure, and the simulated and measured results show that the proposed design offers an ultra-wide bandwidth of 143.2% (from 2.3 to 13.9 GHz).     

Study of printed quasi-self-complementary antenna for ultra-wideband systems

A novel and simple design of a quasi-self-complementary antenna for ultra wideband applications is presented. The proposed antenna, which is fed by a 50 Omega coplanar waveguide without using a matching circuit, can offer an ultra-wide 10 dB impedance bandwidth. It also features a compact and small size, only 0.22 lambda at 1.3 GHz, which is the lower end of the bandwidth. Good agreement is achieved between the simulation and the experiment.     

Compact ultra-wideband printed antenna with band-rejection characteristic

A novel and compact ultra-wideband printed antenna with band-rejection characteristic is proposed. By cutting an L-shaped notch on the radiating patch, the impedance bandwidth of the proposed antenna can be enhanced. In addition, a C-shaped slot is introduced to obtain the band-rejection operation of the antenna. The antenna, with compact size of 15.5/spl times/21 mm including the ground plane, operates over 3.08-10.97 GHz and has the rejected band from 5.03 to 5.91 GHz.     

3D打印的小型化超宽带盘锥天线

在传统双锥天线的结构上,将双锥天线的上圆锥用圆盘替代,形成由一盘一锥构成的倒置盘锥结构的小型化超宽带盘锥天线。该天线满足新型天线的超宽工作频带、小型化、水平全向辐射的性能需求。该天线在实现超宽带性能的同时,也实现了天线的小型化和轻量化。利用电磁仿真软件CST STUDIO SUITE 2017对天线结构设计和参数优化后,采用3D打印技术加工制作了天线样品,其直径仅为74 mm(0. 17λ),高度仅为97. 37 mm(0. 23λ),其中λ为天线工作频段低端对应波长。仿真和测试结果表明,当S11(Return Loss)≤-10 d B时,天线的工作频段为0. 7~17. 1 GHz,相对带宽为184. 3%,其水平全向辐射性能良好,最大增益为6. 63 d Bi,且该天线结构简单,易于加工,具有一定的工程应用价值。     

An offset CPW-fed triple-band circularly polarized printed antenna for multiband wireless applications

An offset coplanar waveguide (CPW)-fed triple-band circularly polarized tilted asymmetrical E-shaped printed antenna for multiband wireless applications is presented in this paper. The antenna mainly consists of a tilted asymmetrical E-shaped patch and excite by a 50 Ω offset CPW feed line using a transformer for impedance matching to generate wide quad operating bands. By properly embedding rectangular slots in the tilted asymmetrical E-shaped patch and triangular stubs loaded modified CPW ground plane, the antenna reveals triple-band circular polarization (CP) features. Numerical analysis and experimental validation of the antenna structure have been carried out and results are presented. The mechanism of triple-band CP operation, analysis of surface current distributions, design procedure, and parametric study of the design is discussed in details. It is well suited for the application of UMTS-2100, 3.5/5.5 GHz WiMAX, 5.2/5.8 GHz WLAN, ITS, downlink of X-band satellite communication, and ITU 8 GHz bands.     

Compact printed ultra-wideband monopole antenna with dual band-notch characteristic

A compact ultra-wideband microstrip-fed planar antenna with dual band-notch characteristic is presented. Two notched frequency bands are achieved by embedding an E-slot in the radiation patch and a U-slot defected ground structure in the feeding line. Moreover, the two notched bands can be controlled by adjusting the length of the corresponding slot. Experimental results show that the proposed antenna, with compact size of 35 x 14 mm, has an impedance bandwidth of 2.87-10.91 GHz for a voltage standing-wave ratio less than 2, except two frequency notched bands of 3.49-4.12 and 5.66-6.43 GHz.     

Band-notched ultra-wideband printed open-slot antenna using variable on-ground slits

A novel modified printed ultra-wideband (UWB) slot antenna with a square structure and a trapezoid tuning stub as well as a band-notch characteristic is presented. By embedding two L-shaped slits at the edge of the open radiating slot, a tunable notched band, for avoiding interference between the UWB and WLAN systems, is achieved. Moreover, by optimising the dimensions of the polygon-like slot and tuning stub, the impedance bandwidth and matching of the antenna can be improved. The realised slot antenna operates over 2.6-13.6 GHz for VSWR < 2 and has a rejected band of 4.9-5.85 GHz.     

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.     

紧凑型共面波导馈电的超宽带印刷天线设计

针对超宽带天线设计的重要性,基于微带天线和电磁散射理论,设计和分析了一种新的紧凑型共面波导反馈超宽带印刷天线。天线采用逆L型和U型非对称的辐射单元结构,以便最大程度地展宽天线带宽。与以往所提出的共面波导馈电天线相比,该天线具有尺寸小、近线性阻抗、高增益、宽频带、准全向性辐射模式和低成本等特点。并且,该天线的主要性能参数达到了一个较好的平衡。仿真和测量结果保持一致。该天线能满足多种宽带无线通信应用的要求。     

应用于WLAN的小型微带天线

为了满足手机无线局域网(WLAN)通信技术的要求,设计了一个三频段单极子贴片天线,通过2个L形支路产生双频辐射。并用软件对该天线进行仿真优化,实现了2.4 GHz、5.2 GHz和5.8 GHz三频段的同时工作,而且该天线结构简单,由L形贴片组合形成,体积小,所占面积为14.5 mm×16.5 mm。仿真结果表明,该天线的尺寸和性能可以在手机WLAN通信系统得到良好的应用     

Channel estimation for ultra-wideband communications

This paper deals with channel estimation in ultra-wideband communications operating in a multipath environment and in the presence of multiaccess interference. The channel parameters are the attenuations and delays incurred by the signal echoes along the propagation paths. Time-hopping modulation with binary symbols is assumed. The estimation method is based on the maximum-likelihood criterion and is applied to two different scenarios: either with known symbols (DA estimation) or with unknown symbols (NDA estimation). The effects of the estimation errors on the performance of a RAKE receiver are assessed by simulation by comparing the receiver bit-error rate with either perfect channel estimates or imperfect estimates as obtained from the proposed algorithms. The results show that the degradations are tolerable as long as the number of users is limited. They also show that the DA method has an edge over the NDA in that it can handle a larger number of users for a fixed degradation. The number of users that can be accommodated in practice is found for some values of the system parameters.