Single-feed dual-band circularly polarised microstrip antenna

A novel technique for obtaining dual-band circular polarisation (CP) radiation of a single-feed circular microstrip antenna is proposed and demonstrated. By embedding two pairs of arc-shaped slots of proper lengths close to the boundary of a circular patch, and protruding one of the arc-shaped slots with a narrow slot, the circular microstrip antenna can perform dual-band CP radiation using a single probe feed. Details of the antenna design and experimental results are presented     

Compact circularly polarised microstrip antenna with bent slots

By embedding a group of four bent slots in a corner-truncated square microstrip patch, a single-feed compact circularly polarised microstrip antenna can easily be obtained. Results show that for a given circular polarisation (CP) operation, the proposed antenna can have an antenna size reduction of more than 50% as compared to the conventional CP design using a corner-truncated square patch without the slots. Moreover, the 50Ω feed position and truncated-corner size for achieving CP operation are found to be nearly independent of the bent slots introduced in the patch, which makes the proposed antenna easy to implement     

Dual-band circularly-polarized square microstrip antenna

New designs of obtaining dual-band circular polarization (CP) radiation of a single-feed square microstrip antenna are proposed and experimentally studied. The proposed single-feed dual-band CP designs are achieved by inserting four T-shaped slits at the patch edges or four Y-shaped slits at the patch corners of a square microstrip antenna. From experiments conducted, a patch size reduction as large as 36% for the proposed design, compared to a conventional CP design without the inserted slits, has been obtained. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band CP performances are presented and discussed     

Dual-Band Bi-Directional Pattern Reconfigurable Fractal Patch Antenna for Millimeter Wave Application

A novel dual-band bi-directional reconfigurable antenna based on Koch patch is presented in this paper. By controlling the switches in the slots etched on the Koch patch, different far field bi-directional patterns at the dual-band around 60 GHz/80 GHz could be achieved. And full azimuthal coverage at this dual-band is possible by electronically controlling the switches in the slots of the patch.     

一款UHF 波段小型化RFID 天线的设计

随着太赫兹成像技术的快速发展,太赫兹成像研究过程中对测试系统提出了大带宽、高性能、通用性强及使用灵活性高等要求,针对这一需求,提出了用通用测试仪器构建太赫兹成像系统的思路:充分利用了通用仪器频率覆盖宽、指标高、通用性强等特点,使得构建的系统指标更高;充分利用了毫米波扩频模块的标准化、模块化设计思路,可实现成像系统测试频段的灵活更换。利用构建的成像系统进行的成像试验结果验证了方法的可行性,能够满足太赫兹成像研究人员快捷方便构建高性能成像系统的要求。     

Miniaturised reconfigurable window slot antenna using mechanical tuning

A novel design approach of varying the slot width on radiating patch of a microstrip antenna for achieving reconfigurable dual-band operation is proposed. The design of this miniaturised reconfigurable antenna is done without the use of active switches or MEMS. The dual band is obtained by rotating the strips on the patch creating slots and varying the slot width using mechanical tuning. The strip is rotated in angular position from 0° to 90° varying the slot width that alters the resonant frequency of the antenna making it resonate at different frequencies covering the wireless bands for global system for mobile communication, global positioning system, wireless local area network and Bluetooth. This antenna provides a dual-band operation that shifts over the bands depending upon the slot width. This antenna achieves the bandwidth requirement and gain in the bands of operation. The effect of change in slot width on the radiation pattern is also discussed. The prototype antenna is fabricated and tested to prove the proposed concept of design. The measured results are in agreement with the simulated results.     

一种新型宽频带三角形微带天线的设计

提出了一种展宽三角形微带天线工作带宽的新方法。通过在三角形微带贴片加载与侧边平行的缝隙来实现双频,添加垂直于底边的缝隙使两个频点靠近,经仿真软件优化后,最终实现频带展宽。仿真结果表明,所设计天线的工作带宽(VSWR<2)是普通三角形微带天线的4倍,且天线尺寸与同频率未加载缝隙的天线相比缩小5%。进行了实物加工与测量,实验结果与仿真结果吻合,证明了所提出方法的有效性。     

Compact circularly polarised microstrip antenna with slotted groundplane

A novel compact circularly polarised microstrip antenna with a slotted ground plane is proposed. By embedding a group of four bent slots in the ground plane and truncating a pair of patch comers in the radiating square patch, the proposed antenna can perform circular polarisation (CP) operation with a reduced antenna size at a fixed operating frequency. In addition, enhanced CP bandwidth and antenna gain for the proposed design are observed. Details of the antenna design and experimental results are presented and discussed     

一种以空气为基板的圆极化微带天线的设计

设计了一种以空气为基板的超高频（UHF）圆极化矩形微带天线。该天线通过在微带贴片四周与中心开槽,减小了天线尺寸,实现天线圆极化的性能。进一步研究了天线的参数对圆极化性能的影响,通过天线参数的优化,使天线达到了良好的圆极化性能。     

太赫兹双频缝隙贴片天线的设计

提出了一种工作在太赫兹频段的双频缝隙贴片天线。在天线辐射贴片上加载“C”、“E”型辐射缝隙,改变天线表面电流的路径来实现双频特性。通过HFSS 15.0仿真软件对天线模型进行仿真,天线可以同时在300 GHz(291～306 GHz)和640 GHz(632～656 GHz)的频段下工作,最大增益达到了7.38 dB和10.50 dB。该双频天线结构简单,各项性能指标稳定,对于工作在太赫兹频段上的通信系统和无线传输系统具有一定的应用价值。     

Circularly polarised antenna with switchable polarisation sense

The authors present the design of a wideband circularly polarised antenna with switchable polarisation sense. The basic antenna is a circularly polarised aperture coupled patch antenna with a slot excitation located along the diagonal of a rectangular patch. A second slot is added along the other diagonal and beam-lead pin diodes are inserted in both slots to allow a dual sense operation for a compact structure in a 4% CP bandwidth     

Circular polarised microstrip patch antennas for broadband and dual-band operation

A novel design of microstrip patch antennas for circular polarisation (CP) is proposed. As an example, two CP patch antennas are investigated: a broadband CP patch antenna and a dual-band CP patch antenna. The proposed structure can be achieved by embedding circular holes in the microstrip circular resonator. By changing the size and position of loaded holes, two orthogonal modes are simultaneously excited with equal amplitude and /spl plusmn/90/spl deg/ out of phase. Without any 90/spl deg/ phase-shifter, the proposed CP patch antennas are excited by single feed.     

Reconfigurable dual-band circularly polarized microstrip patch antenna for wireless applications

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.     

一种双频双圆极化微带天线的设计

提出了一种仅利用单端口馈电的共口径双频双圆极化微带天线。天线通过在对应高端谐振频率的圆形贴片外层附加对应低端谐振频率的圆环形贴片,并采用四个窄带条连接两贴片,从而实现双频工作;通过在圆形和圆环形贴片外侧开缺口的方式实现了圆极化波辐射,并通过在两贴片上开置的缺口相正交,从而形成了低端右旋圆极化（RHCP）、高端左旋圆极化（LHCP）的特性。对提出的天线进行了仿真并优化设计,给出了该天线在两个谐振频段上具有较好的阻抗匹配和双圆极化性能。     

Dual-Band Circularly Polarized Dual-Slot Antenna With a Dielectric Cover

A new circularly-polarized (CP) dual-slot antenna fed by a single L-probe is proposed for dual-band applications. The antenna consists of a zonal slot and an annular slot, both of them being cut onto a square conducting cavity with a protective dielectric cover. It is observed that the resonance frequencies of the lower and upper bands are controlled by the zonal and annular slots, respectively, making designs of the dual-band antenna very easy. To demonstrate the idea, the proposed antenna was designed at 2.4/5.8 GHz for two IMS bands. The reflection coefficient, axial ratio, radiation pattern and gain of the dual-band antenna were studied, and reasonable agreement between the simulated and measured results was obtained. A parametric study was carried out to characterize the proposed antenna.      

Gain enhancement of a circularly polarized equilateral-triangular microstrip antenna with a slotted ground plane

A novel circular polarization (CP) design of a single-feed equilateral-triangular microstrip antenna with enhanced antenna gain is presented. This CP design is obtained by placing three triangular slots at properly locations below the equilateral-triangular radiating patch in the ground plane. By adjusting one of the triangular slot's side lengths slightly longer than that of the others, two orthogonal near-degenerate resonant modes for CP radiation can be excited. Measured antenna gain in this study can easily be increased by 3.3 dBi (5.1 dBi versus 1.8 dBi), as compared to the same height, substrate material, operating frequency and radiating patch shape of a regular equilateral-triangular microstrip antenna without triangular slots in the ground plane. Prototype antenna is fabricated for experimental evaluation. Simulated and measured results are presented.     

应用于北斗和GPS的双频小型圆极化微带天线

介绍了一款能同时应用于北斗卫星导航系统B₃频段(1 268 MHz,±10 MHz)和全球卫星导航系统(GPS)L₁频段(1 575 MHz,±2 MHz)的双频小型圆极化微带天线,并通过叠层技术实现了天线的双频工作性能。采用相对介电常数为9.7的介质材料和表面开槽技术减小了天线尺寸,达到了小型化的要求。通过切角的方法实现了天线的右旋圆极化工作方式。同时,利用基于有限元法的HFSS仿真软件对天线进行了参数仿真和调试。仿真结果表明,在B₃频段天线具有2.2%的阻抗带宽(VSWR<2)和0.5%的3 dB轴比带宽,在L₁频段天线具有3.1%的阻抗带宽(VSWR<2)和0.5%的3 dB轴比带宽。天线仿真结果满足北斗和GPS指标要求,因此具有良好的应用前景。     

Patch antennas with switchable slots (PASS) in wireless communications: concepts, designs, and applications

This feature article describes, in a comprehensive and unified fashion, the authors' work on the development of novel kinds of reconfigurable microstrip antennas: patch antennas with switchable slots (PASS). PASS are versatile for wireless communication systems, and their structure is very simple. This article introduces the operational mechanism of PASS, as well as their frequency-ratio control and input impedance tuning. Various PASS designs are presented to demonstrate the capability of PASS in wireless communication. These designs demonstrate the functions of dual-frequency operation, dual-band circular-polarization performance, and circular-polarization diversity with only one layer and a single feed. A practical PASS application for future Mars rover missions is also highlighted: a compact, dual-band, circularly polarized antenna for the UHF band was designed, fabricated, and measured, based on the PASS concept.     

小型圆极化环形微带天线的设计

提出一种新的小型圆极化环形微带天线,通过在环形贴片内外边缘非主要辐射区域开一组狭长缝隙获得小型化特性,在环形贴片内边缘135°、315°处相对位置开一对调谐窄缝隙实现圆极化,并用带状线在环形贴片内边缘馈电.这种天线表现出了极好的圆极化特性而且很容易在低频段匹配到50Ω,与普通带状线馈电圆极化环形微带天线相比,天线谐振频率下降,尺寸缩小了近50%.     

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.