Dual-Frequency Operation of Bow-Tie Microstrip Antenna

Characteristics of a single-feed dual-frequency bow-tie microstrip antenna are studied. By using the variation method, simple formulas for resonant frequencies of the bow-tie microstrip antenna are derived. It is shown that the dual-frequency ratio can be controlled easily by choosing the parameters of the antenna. This design gives compact antenna size and simple antenna structure. Experimental results are presented, verifying the validity of the design.

Ultra-wideband bilateral tapered slot-line antenna fed by coplanar waveguide

In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.

Multi-Reconfigurable Band-Notched Coplanar Waveguide-Fed Slot Antenna

This paper proposes an antenna design concept to achieve a multi-reconfigurable band-notch antenna by using a set of microswitches. The proposed idea was proved by the design of the coplanar waveguide(CPW)-fed slot antenna. The sample design gives a wideband antenna the impedance bandwidth of which covers the frequency ranged from 1.9 GHz to 6.55 GHz.The antenna could be configured to work either in single-band mode or in one of the defined dual-band modes.

A Linear Array Antenna of Microstrip Patch Antennas Fed by the Open-End of Coplanar Waveguides

In this study, we constructed a 4-element linear array antenna using four 20 GHz band microstrip patch antennas with a structure such that the signal is fed to the patch antennas from open-end coplanar waveguides without contact. We investigated factors related to the design of linear array patch antennas. To adjust the maximum radiation direction and reduce return loss, we optimized the spacing between the elements and their shape. With an element spacing of 11.50 mm, patch width of 3.90 mm, and patch length of 4.15 mm, we obtained a resonance frequency of 20.05 GHz and a return loss of -29.59 dB at the resonance frequency. However, in the case of a 4-element linear array antenna structure, undesired resonances occurred in frequency bands other than the design resonance frequency band of 20 GHz. To suppress these undesired resonances and obtaining stable operation at the design frequency, we propose a new structure in which the feed line is loaded with a short stub, and show through computer simulations that the occurrence of undesired resonances can be sufficiently suppressed. Furthermore, we demonstrate the problem of radiation gain reduction caused by introducing a short stub, propose a design method for a new structure in which the feed line has slits between the stubs, and show improvement of the antenna gain by 0.5 dBi.

A novel and simple coplanar waveguide-fed planar monopole antenna for ultra-wideband applications

In this paper, a novel and simple CPW-fed planar monopole antenna is presented for UWB application. The antenna is fabricated on inexpensive FR4 substrate and fed by 50Ω CPW on the same layer, Measured data show that the antenna provides an impedance bandwidth of about 8GHz for the return loss less than 10dB. It is also observed that the radiation pattems are nearly omni-directional over the entire frequency range. Details of the proposed antenna are presented, and simulated results are presented and discussed.

基于石墨烯片的频率可调太赫兹天线

本文设计了一种基于石墨烯片的频率可调太赫兹天线,采用了折叠缝隙结构并使用共面波导馈电方式,以更好地实现阻抗匹配.通过调控在缝隙之间添加的4个石墨烯片的电导率,改变缝隙天线的等效长度,使天线在两种不同工作模式下的谐振频率分别为230.5 GHz和270.5 GHz.除此之外,在天线下方加载了方形封闭谐振环(Closed-Ring Resonator,CRR)构成的超表面,并使其谐振频率与天线的谐振频率匹配,将z轴负方向的辐射进行反射,使天线在两种工作模式下的增益提高至5.41 dBi和7.63 dBi,与无反射结构时相比分别增长2.48 dBi和3.55 dBi.

一种新型共面波导馈电Ku波段准八木贴片天线的设计

本文设计了一种中心频率为15 GHz、基于共面馈电结构的Ku波段准八木“贴片”天线,该天线结构相对简单、工作频段较宽并且具有较高的增益特性。该设计通过分析、添加并且优化寄生竖向“贴片”的方式实现特定频率范围内电感或电容的改变,从而达到提高天线带宽的目的。研究还表明:在两侧竖向“贴片”的两端添加横向“贴片”,通过调整横向“贴片”的方向,以及改变寄生贴片的参数,可以进一步地提高天线带宽。本设计提出的准八木“贴片”天线的工作频段比初始天线相对带宽提高了13.3%,工作频带内峰值增益达到8.3 dBi,平均增益达到7.5 dBi,工作频带内平均效率为75%。该新型天线可广泛应用于无线通信系统中,并可用作阵列元为设计相控阵、有源阵列以及毫米波成像阵列提供支持。

一种用于应急通信的双枝节可穿戴织物接收天线研究

随着现代应急系统的逐渐完善与通信技术的飞速发展,应急单兵通信装备中的天线结构正朝着小型化和可共形化的方向发展,通信频段朝着多频段和宽带化的方向发展。天线作为无线通信系统中重要的无线收发器件,其通信性能对无线通信系统影响至关重要。本文通过高频仿真软件HFSS研究设计了一款可用于应急救援的双枝节结构共面波导织物天线,并通过射频基础公式计算出谐振频点,以简单的双枝杈结构作为辐射体,接地面为倒三角形,使整体表面结构能与臂章共形,达到可穿戴的目的。其覆盖的频段为1.5~2.09GHz和2.54~3.09GHz,增益为0.1~2.9 dBi,效率为53%~60%。该天线可用于2G、FDD、F频段、5G中2.6 GHz频段和卫星接收频段。

基于共面波导的超宽带环形天线设计

阐述设计的一种安装在PCB基板上的超宽带天线,采用共面波导馈电,通过加载一个环形辐射贴片,在馈线上切割一个插槽,以提高辐射特性。该天线用于物联网设备、超宽频段和部分x波段等。

Ultra-wideband printed antennas for communication applications

A new type of ultra-wideband （UWB） printed monopole antennas is presented, which is composed of a circular or armular patch and a trapeziform ground plane with a tapered CPW feeder in the middle. Both simulated and experimental results are presented, showing good agreement and therefore verifying validity of the design. The proposed antenna with a circular monopole patch achieves an 11.6： 1 measured ratio bandwidth of VSWR ≤2 （ from 0,79 GHz to 9.16 GHz）, while that with an annular patch obtains a measured ratio impedance bandwidth of 10.6：1 （from 0.87 GHz to 9.47 GHz）. In addition, these designs exhibit nearly omnidirectional radiation patterns with simple compact structures, which axe attractive in communications and others UWB applications.

A NOVEL WIDEBAND ANTENNA DESIGN USING U-SLOT

U-slot patch antennas with П-shaped feed slot are studied, and numerical results based on the FDTD method are presented. The effects of varying physical parameters are investigated with a goal of understanding the coupling among different resonators. It is found that the U-slot patch antenna can be designed to attain 50% impedance bandwidth as well as 30-40% gain bandwidth. By altering the sizes of U-slot and feed slot, the wideband characteristic can be changed into a duai-frequency char- acteristic.

Design of a CPW-Fed Ultra Wide Band Antenna

A CPW-fed ultra-wideband antenna was designed. The antenna was etched on a single-layer copper-cladding substrate, of which the material was FR4 with relative permittivity of 4.4, and the magnitude was 40.0 mm × 50.0 mm × 1.6 mm. The parameters of the antenna are simulated and optimized with HFSS. This paper proposes a new trapezoidal CPW-fed UWB antenna that the bandwidth (return loss ≤ ?10 dB) covers 2.7 - 9.3 GHz range, which means a relative bandwidth of 110% with good radiation patterns and gain. Simulated and measured results for return loss, radiation pattern and gain were presented. A good agreement has been obtained between the simulation and experiment and the proposed antenna meets the requirements of the ultra-wideband antenna.

Novel Balun Structure for Dipole Antenna

A novel balun structure for dipole antenna,which is based on the current distribution on parallel microstrip lines and the emission cancellation characteristic of close equal and opposite currents,is proposed.The principle of the balun structure is first elaborated and verified.Then,a dipole antenna with resonance at 2.45 GHz is constructed using the balun and its radiation pattern is measured.The simulated and measured reflection coefficients(S_(11))of the antenna are in good agreement 2—3 GHz.The relative bandwidth with an S_(11) of below-10 dB is more than 25%.The antenna also shows a good radiation pattern at 2.45 GHz.The proposed structure can provide a new balun design method for dipole antennas.

Multiband printed monopole and dipole antenna with square-nested fractal

A kind of novel muhiband antenna with square-nested fractal is proposed and designed, including printed monopole antenna and dipole antenna, which are nested with a series of similar square elements. The antennas can synchronously operate in multiple frequencies, covering the four required frequencies, 2.4GHz/ 3.5GHz/5.2GHz/5.8GHz, for WLAN/WiMAX application. The antenna surface currents are simulated by CST MWS, a three-dimension full-wave electromagnetic simulator, and the multiband operating mechanism has been explained from analysis of the simulation results. Then the models of the two proposed antennas fed by coplanar waveguide （monopole antenna） and balanced microstripline （dipole antenna）, respectively, have been obtained. Finally, prototypes of the two antennas have been manufactured and measured in anechoic chamber. The results well match the simulation results, which verifies the feasibility of design idea. Moreover, these antennas are miniature and the design idea can be easily applied into other types of nested structure, the features of which make the Proposed antennas have promising application in muhiband fields.

Frequency Reconfigurable Antenna for Portable Wireless Applications

In this paper,the design and experimental evaluation of a hexagonalshaped coplanar waveguide(CPW)-feed frequency reconfigurable antenna is presented using flame retardant(FR)-4 substrate with size of 37×35×1.6 mm3.The antenna is made tunable to three different modes through the status of two pin diodes to operate in four distinct frequency bands,i.e.,2.45 GHz wireless fidelity(Wi-Fi)in MODE 1,3.3 GHz(5G sub-6 GHz band)in MODE 2,2.1 GHz(3G Long Term Evolution(LTE)-advanced)and 3.50 GHz Worldwide Interoperability for Microwave Access(WiMAX)in MODE 3.The optimization through simulation modeling shows that the proposed antenna can provide adequate gain(1.44∼2.2 dB),sufficient bandwidth(200∼920 MHz)and high radiation efficiency(80%∼95%)in the four resonating frequency bands.Voltage standing wave ratio(VSWR)<1.5 is achieved for all bands with properly matched characteristics of the antenna.To validate the simulation results,fabrication of the proposed optimized design is performed,and experimental analysis is found to be in a considerable amount of agreement.Due to its reasonably small size and support of multiple frequency bands operation,the proposed antenna can support portable devices for handheld 5G and Wireless LAN(WLAN)applications.

Ultra-Wideband Log Periodic Dipole Antenna (LPDA) for Wireless Communication Applications

This paper proposes a printed log-periodic dipole antenna (LPDA) for ultra wide bandwidth (UWB) applications. The antenna comprises of cascading four U shaped elements of different line lengths with balun circuit to improve the antenna impedance matching. The proposed antenna dimensions are 50 × 50 mm2 with FR4 substrate thickness 0.8 mm. Full-wave EM solver HFSS (High Frequency Structure Simulator) is used for modeling the proposed antenna. The pulse distortion is verified by the measured the proposed antenna performance with virtually steady group delay. The simulation and experimental results show that the proposed antenna exhibits good impedance matching, stable radiation patterns throughout the whole operating frequency bands, acceptable gain and stable group delay over the entire operating band. An UWB extended from 1.85 GHz to 11 GHz is obtained, and the average antenna gain is about 5.5 dBi over the operating band with peak gain around 6.5 dBi and 70% average radiation efficiency.

Analysis and design of compact printed monopole UWB antennas with multiple notched bands

This paper presents three compact ultra-wideband(UWB)antennas fed by coplanar waveguide(CPW).The proposed antennas consist of a planar circular patch monopole UWB antenna and multiple etched slots on the feed line.Simulation by Ansoft high frequency structure simulator(HFSS)10.0 shows that the in-band impedances are quite stable and satisfactory.Rejected narrow frequency bands are further obtained within the wideband width by inserting U-shaped slots into the fed line of the antennas.The antennas have a dimension of 50mm by 40mm by 1.5mm.The simulation and measurement results show that the proposed antennas have stable directional radiation patterns,very low profile and low fabrication cost,which are suitable for the UWB system.

用于UHF RFID和WLAN双频段的智能手套天线

为解决智能手套中RFID(Radio frequency identification)阅读器天线在WLAN频段数据分发问题,设计了一种工作于UHF RFID和WLAN双频段的小型化可穿戴天线。采用非对称共面技术缩小天线接地面积,通过折叠天线辐射体实现双频工作,同时可进一步缩小天线面积。将天线附着于不同材质的手套及不同穿戴者身上测试天线的鲁棒性,对辐射方向图与比吸收率进行仿真分析以验证天线的辐射特性与安全性。结果表明:天线在900 MHz和2.40 GHz处实测工作频段分别为0.69~1.03 GHz、1.29~3.00 GHz,可实现UHF RFID与WLAN频段通信。改变手套材质和测试者体型时,天线仿真与实测回波损耗相接近,具有较宽带宽。该天线设计简单、性能稳定,且辐射方向稳定,对人体危害较小,在智能手套领域具有一定应用前景。

面向车载GPS应用的共面波导馈电光透明天线

本文以车载GPS应用为基点,以氧化铟锡(ITO)透明导电薄膜为关键材料,设计了一款共面波导馈电的圆极化可见光透明天线。所提出的天线通过将T形贴片从接地板水平延伸向矩形缝隙中心获得圆极化波,在保证80%透明度的前提下实现了575MHz的阻抗带宽和285MHz的轴比带宽,以及3.1dBic的天线增益和47%的辐射效率。天线具有良好的辐射特性,在车载场景等有广泛的应用前景。

小型化超宽带叶型微带单极子天线设计

针对目前超宽带(UWB)微带单极子天线带宽较窄以及尺寸较大等缺点,文中提出一种基于共面波导(CPW)馈电的小型化超宽带微带单极子天线。该天线由叶型的辐射贴片(其上挖去3个圆形贴片)、梯形地板和环形三叉戟共面馈电组成,可实现1~18 GHz的超宽带频率覆盖。使用HFSS软件对天线的结构和尺寸进行分析,得出最终的天线尺寸仅为40 mm×75 mm×0.5 mm。利用矢量网络分析仪进行测试,结果表明,所设计的天线具有179%的相对带宽,在1~18 GHz的工作频段内阻抗匹配良好,并且具有良好的辐射性能;且该天线的工作频率能够实现L波段、S波段、C波段、X波段以及Ku波段的多个频率覆盖,具有超宽带的优良性能。