Broadband Active Receiving Patch With Resistive Equalization

The active integrated antenna (AIA) concept has been applied to design a broadband receiver front-end. A design procedure for active broadband patch antennas based on resistive equalization is presented. The use of the AIA has allowed the design of efficient RF front-ends by increasing its effective gain, noise figure, and merit . In addition to improving the classical parameters, the resistive equalization technique allows enlarging the bandwidths of the active antenna parameters versus the corresponding ones in passive antennas. A receiving patch antenna (with one amplifying stage) with a measured noise figure lower than 0.6 dB in a bandwidth over 38% and an effective gain improvement of 13 dB over the corresponding passive antenna has been achieved. The -parameter has also been measured for both the active and passive antenna, resulting in a relative planar of 16 dB/K, with a ripple of 0.5 dB, over a 30% bandwidth for the active antenna versus a of 22 dB/K for a typical front-end with a passive antenna over 20% bandwidth.     

Truncated spherical helical antennas

The truncated spherical helix is presented as a compact circularly polarised antenna with relatively high gain and moderate bandwidth. A numerical investigation into the radiation properties of this antenna is also presented. The antenna provides a directivity of >9 dB and an axial ratio of <3 dB over a 10% bandwidth. The radiation pattern has a broad main beam and better than 20 dB front-to-back ratio     

Broadband printed circularly-polarised aperture antenna array for millimetre-wave gigabit applications

A simple and successful design of a printed aperture antenna array is presented in view of high-speed millimetre-wave wireless access applications. The antenna element design is based on a broadband travelling- wave aperture antenna for circularly-polarised radiation. For the antenna array design, the sequential rotation scheme is employed for improving the co-polarised gain and axial ratio. The presented antenna array is designed in the 40?48 GHz band and implemented with a 5mil-thick RT/Duroid-5880 PCB. Promising performances are achieved, including a return loss (,10 dB) bandwidth of 32%, an axial ratio (,3 dB) bandwidth of 25%, and a co-polarised gain (flatness , 3 dB) bandwidth of 32% with a maximum gain of 11dBic.     

A novel design of circularly polarised antenna based on metamaterial

This article presents a novel design of circularly polarised microstrip antenna based on a metamaterial reflection plane and a half-wave antenna. The metamaterial is composed of two pieces of substrates coated on one side with split ring resonators. Both the experimental and simulated results show that good circularly polarised radiation performances are obtained. The 10?dB return-loss impedance bandwidth and 3?dB axial ratio bandwidth of proposed antenna are 12% and 7%, respectively, and the gain of proposed antenna compared with the half-wave antenna is improved from 6?dB to 9?dB in the design frequency range.     

Wideband and high-gain one-patch microstrip antenna coupled withH-shaped aperture

The design, fabrication, and experimental implementation of the one-patch microstrip antenna coupled with an H-shaped aperture are presented. The presented antenna has a wide bandwidth, high gain, and low cross-polarisation levels with only one-patch. The measured bandwidth of this antenna is 56.2% for the voltage standing wave ratio ⩽2.0. The cross-polarisation level is below -18.2 dB at the E-plane and below -25.7 dB at the H-plane. The maximum gain at 2.05 GHz is 10.4 dBi and the 3 dB gain bandwidth with a centre frequency at 2.17 GHz is 24%     

Design of dual-polarized L-probe patch antenna arrays with high isolation

An experimental study of a dual-polarized L-probe patch antenna is presented. The antenna is designed to operate at around 1.8 GHz. A "dual-feed" technique is introduced to achieve high isolation between two input ports. The proposed antenna has an impedance bandwidth of 23.8% (SWR/spl les/2), 15% (SWR/spl les/1.5) and an isolation over 30 dB. In array designs, techniques for improving the isolation between two adjacent elements of an antenna array are also investigated. A two-element array with more than 30 dB isolation is designed and tested.     

基于复合腔结构的MEMS双模微带天线设计

设计了一种基于腔结构的双模偶极子天线,其频率在2.44GHz和4.38GHz,利用MEMS开关实现双波段的操作.根据偶极子天线原理,设计了单模微带偶极子天线,使用开关结构将两个单模偶极子天线连接在一起,实现了双模天线的功能.利用三维电磁场软件HFSS分析了设计结构,包括开关、天线,在0～10 GHz得出开关性能插入损耗在-1dB以下,天线回波损耗在-26dB以下.频率为2.44GHz时、回波损耗为-13.2dB、2dB的辐射效率为89%,频率为4.38GHz时,回波损耗为-21.9dB、3dB辐射效率为96%,带宽都在0.5GHz左右.     

Design of Dual‐Band MIMO Antenna with High Isolation for WLAN Mobile Terminal

In this paper, we propose a dual‐band multiple‐input multiple‐output (MIMO) antenna with high isolation for WLAN applications (2.45 GHz and 5.2 GHz). The proposed antenna is composed of a mobile communication terminal board, eight radiators, a coaxial feed line, and slots for isolation. The measured ?10 dB impedance bandwidths are 10.1% (2.35 GHz to 2.6 GHz) and 3.85% (5.1 GHz to 5.3 GHz) at each frequency band. The proposed four‐element MIMO antenna has an isolation of better than 35 dB at 2.45 GHz and 45 dB at 5.2 GHz between each element. The antenna gain is 3.2 dBi at 2.45 GHz and 4.2 dBi at 5.2 GHz.     

A broadband planar quasi-Yagi antenna

A novel broadband planar antenna based on the classic Yagi-Uda dipole array is presented. This "quasi-Yagi" antenna achieves a measured 48% bandwidth for VSWR <2, better than 12 dB front-to-back ratio, smaller than -15 dB cross polarization, 3-5 dB absolute gain and a nominal efficiency of 93% across the operating bandwidth. Finite-difference time-domain simulation is used for optimization of the antenna and the results agree very well with measurements. Additionally, a gain-enhanced design is presented, where higher gain has been achieved at the cost of reduced bandwidth. These quasi-Yagi antennas are realized on a high dielectric constant substrate and are completely compatible with microstrip circuitry and solid-state devices. The excellent radiation properties of this antenna make it ideal as either a stand-alone antenna with a broad pattern or as an array element. The antenna should find wide applications in wireless communication systems, power combining, phased arrays and active arrays, as well as millimeter-wave imaging arrays.     

一种带有新型馈电结构的宽带印刷角锥四臂螺旋天线

本文提出一种新型馈电结构的印刷角锥四臂螺旋天线。通过采用柱面共形结构馈电网络,与传统四臂螺旋天线相比极大地减小了地板安装面积及改善了阻抗带宽和轴比带宽。S11小于-10dB的阻抗带宽可达39.7%,3dB轴比带宽约22%。测试与仿真结果吻合良好。     

一种新型布局的圆极化微带天线阵优化设计

提出了一款高增益低副瓣新型圆极化微带天线阵。单元天线采用叠层切角圆极化微带结构,通过八边形边界布局和顺序旋转交叠组阵技术,实现了天线阵方向性图的对称性和圆极化辐射性能的最优化;馈电网络采用威尔金森功分器和最大平坦式阻抗变换器实现不等功分宽带阻抗匹配,通过改进馈电方向寻求对称结构,简化了馈电网络的设计。制作了天线阵实物并进行了测量。测试结果表明:天线在3.2~4.6 GHz频段内S₁₁<-10 dB,阻抗相对带宽36%;在3.8~4.5 GHz频段内顶点轴比小于3 dB,圆极化相对带宽17%;在4~4.4 GHz频段内天线增益均在15 dB以上,最高增益达17 dB。     

Broadband circularly polarised hexagonal slot antenna excited by a tapered microstrip feeder

In this article, a broadband circularly polarised slot antenna fed by a single microstrip line is implemented. The proposed antenna is composed of an unequilateral hexagonal slot to implement circular polarisation and tapered microstrip feeding line to enhance the impedance bandwidth. A conducting reflector is also employed to enhance the antenna gain. The proposed antenna, 60 mm × 60 mm × 18.12 mm in size, was fabricated and tested. The measured??10 dB reflection bandwidth and 3 dB axial ratio bandwidth were 48.9% and 17%, respectively. The measured gain of the fabricated antenna ranged from 5.4 dBi to 6 dBi within an axial ratio bandwidth of 3 dB.     

基于超表面的低剖面高增益圆极化天线

提出了一种基于缝隙耦合超材料表面的低剖面圆极化高增益天线,该天线由一个超材料表面和一个微带缝隙天线紧贴着组成. 通过改变超表面切角的大小来产生圆极化波,同时还可以提高天线增益和拓宽阻抗带宽. 为了验证仿真结果,制作和测量了一个大小为1λ×1λ×0.067λ(在10 GHz处)的样本天线,仿真和测量结果显示出良好的一致性. 结果表明,在整个工作带宽内天线的增益均在7.5 dB以上,最大增益达到10.5 dB,比普通缝隙天线提高了5.3 dB,阻抗带宽(S₁₁ < ?10 dB)为27.4%,轴比带宽(AR < 3 dB)达到12.3%. 因此,该天线能同时满足低剖面、圆极化、高增益等多种性能的要求,可以应用于许多领域.     

H 形缝隙耦合双极化微带天线阵设计分析

设计并仿真了一种基于H 形缝隙耦合馈电,工作在u K 波段的微带双极化天线,并进行了4 单元平面组阵。4 单元阵实现的指标：驻波小于2 的相对带宽达到8.2%,双极化端口隔离度达-32dB,交叉极化达-23.5dB,方向图前后比 达-28dB,增益达到15dB,3dB 增益带宽达23.2%,并且两种极化下天线方向图有较好的一致性。天线采用多层结构,减 小了天线尺寸,并且两组馈电在不同夹层的设计使得进一步组阵变得便利,适应了双极化合成孔径雷达及抗多径干扰高 的移动通信系统的需要。     

A 94-GHz aperture-coupled micromachined microstrip antenna

This paper presents an aperture-coupled micromachined microstrip antenna operating at 94 GHz. The design consists of two stacked silicon substrates: (1) the top substrate, which carries the microstrip antenna, is micromachined to improve the radiation performance of the antenna and (2) the bottom substrate, which carries the microstrip feed line and the coupling slot. The measured return loss is -18 dB at 94 GHz for a 10-dB bandwidth of 10%. A maximum efficiency of 58±5% has been measured and the radiation patterns show a measured front-to-back ratio of -10 dB at 94 GHz. The measured mutual coupling is below -20 dB in both E- and H-plane directions due to the integration of small 50-μm silicon beams between the antennas. The micromachined microstrip antenna is an efficient solution to the vertical integration of antenna arrays at millimeter-wave frequencies     

A dual polarized aperture coupled circular patch antenna using a C-shaped coupling slot

The design and development of a dual linearly polarized aperture coupled circular microstrip patch antenna at C-band are presented. The antenna uses a novel configuration of symmetric and asymmetric coupling slots. Variations in isolation between orthogonal feedlines and antenna axial ratio with the position of coupling slots are studied and broadband isolation and axial ratio are achieved. The prototype antenna yields 7.6 dBi peak gain, 70/spl deg/ 3-dB beam width, 25 dB cross-polarization levels and an isolation better than 28 dB between the two ports. With an external quadrature hybrid coupler connected to the two orthogonal feedlines, the antenna yields 3-dB axial ratio bandwidth of more than 30% at 5.8 GHz.     

RCS reduction and gain enhancement of SRR inspired circularly polarized slot antenna using metasurface

In this work, a novel Circularly Polarized (CP) slot antenna is proposed for low RCS and high gain applications. The proposed antenna is designed in two phases. Initially, a metasurface is designed, which is composed of two similar artificial magnetic conductor (AMC) unit cells arranged orthogonally in chessboard-like configuration for broadband RCS reduction. Then, the CP slot antenna is designed by placing dual SRR on the backside of the slot for impedance matching and to achieve circular polarization. Detailed analysis is conducted to investigate the performance of metasurface loaded CP slot antenna. The proposed antenna shows 10 dB RCS reduction over the bandwidth of 41.3% at boresight direction compared to CP slot antenna. The maximum in-band and out-of-band RCS reduction achieved is 24 dB and 20 dB, respectively. The maximum gain of the antenna is also increased by 2.7 dB as a result of parasitic radiation of the metasurface and an improvement in overall performance of the antenna is observed by the employment of metasurface. Measured results of the fabricated prototype are in good agreement with the simulated results.     

A 24-GHz high-gain Yagi-Uda antenna array

A compact 24-GHz Yagi-Uda antenna has been developed using standard design tables and simple scaling to take into account the added capacitance due to the supporting dielectric substrate. The antenna results in a directivity of 9.3 dB, a front-to-back ratio of 11 dB, and a bandwidth of 2.5-3%. The Yagi-Uda antenna has been implemented in an 11-beam system using a planar array and a 2-inch Teflon spherical lens. The measured patterns show a 22 dB gain beam, a cross-polarization level of -24 dB, and a crossover level of -6 dB. The design method presented in this paper is quite straightforward, and can be used to develop low-, medium-, and even high-gain endfire Yagi-Uda antennas.     

一种新型CPW 馈电宽带圆极化缝隙天线

设计了一种新型的CPW 馈电宽带圆极化缝隙天线,圆形槽天线与共面波导馈电在介质板的同面上。通过在 两个圆形槽的中间开一个纵向插槽,调整槽之间的相对位置和各自的几何参数,可以得到一个由两个正交九十度相位 差的电场激发的圆极化波。最终仿真结果表明该天线在频带1.0GHz 到1.8GHz 满足反射系数小于-10dB、轴比小于3dB, 相对带宽达到57%,工作频带覆盖了GPS 等卫星导航系统。该天线具有十分紧凑的平面结构,结构简单,容易加工, 便于实验调试,具有广阔的应用前景。     

A printed hemispherical helical antenna for GPS receivers

A self-matched printed hemispherical helical antenna for potential use in global positioning system receivers is introduced. Unlike wired hemispherical helical antennas, its printed form renders it a much more stable and endurable structure and also easier for fabrication. The optimized antenna shows an impedance bandwidth of 6%, a 3-dB axial ratio bandwidth of 6%-7%, a return loss greater than 20 dB, and a gain of about 9 dB at the center frequency. The patterns of the antenna show a larger mainlobe in the upper half space with relatively small backlobes. Both theoretical and experimental results was presented.