一种K频段宽带双极化滤波喇叭天线设计

文中设计了一种K频段宽带双极化滤波喇叭天线,该天线采用阶梯型喇叭代替传统喇叭提升了天线效率,并通过在馈电波导冗余空间中引入一种T/Π型滤波结构,提升了天线带外的抗干扰能力. 仿真和实验结果表明,该双极化天线的?10 dB阻抗带宽超过5 GHz,覆盖了K/Ka频段卫星的下行频段,天线效率超过58%,并在其上行频段实现了超过33.1 dB的带外抑制,该天线可作为单元用于K/Ka频段卫星下行频段的大型阵列天线设计.     

Ka频段宽带圆极化微带天线

面向Ka频段高通量卫星对天线的需求,设计了一种Ka频段宽带圆极化微带天线.天线单元主要由圆形辐射贴片和缝隙耦合馈电结构组成,通过两个类T形缝隙结合实现宽带圆极化.天线仅有三层金属层,结构简单.仿真结果显示,天线单元的相对阻抗带宽为31.5%(25.1～34.5 GHz),相对3 dB轴比带宽为20.3%(26.5～32.5 GHz).由于单元尺寸较小,不便于对其性能进行验证,因此利用该天线单元组成2×2天线阵列,并进行加工测试.仿真与试验结果表明,天线阵列阻抗带宽以及3 dB轴比带宽可以覆盖25.6～33.1 GHz频率范围,实测结果与仿真结果一致性良好.     

应用于物联网MIMO天线的双频谐振解耦结构

提出了一种用于双频MIMO天线的谐振器去耦结构。通过双频单极子MIMO天线对该解耦结构进行验证。双频单极子天线分别工作在低频2.4GHz和高频5.8GHz。 双频解耦结构在低频段主要是采用两个反向的π型微带谐振器解耦,高频段主要是采用π型缝隙谐振器解耦。天线采用微带线馈电,解耦谐振器与天线地板印刷在PCB同一面,结构紧凑易于与系统集成,可以广泛应用于物联网通信系统中。 实测结果：双频谐振器去耦结构实现隔离度高于22dB,单极子天线阻抗带宽分别为2.0GHz-3.0GHz和5.0-6.0GHz（S11<-10dB）,低频段增益最大增益点1.5dBi,高频段最大增益点3dBi。     

高隔离度微带阵列天线的设计

提出了一种通过增加曲折开槽谐振器来增强阵列天线单元间隔离度的方法。首先设计了一款应用于802.11ac(5.17~5.29 GHz)频段移动终端的天线,在其阵列单元间添加一个曲折的开槽谐振器,此谐振器具有带阻特性,能有效降低天线单元间的互耦,增强天线单元间的隔离度,并利用HFSS软件对微带阵列天线进行了仿真与优化。仿真结果显示,增加了开槽谐振器后天线的隔离度增强了11.31 dB,隔离度达到了–29.4 dB,驻波比VSWR小于1.35,S11小于–16 dB,S21达到了–26 dB,满足天线的要求。     

基于宽带极化转换超表面的天线RCS缩减

针对天线隐身问题,设计了一款宽带极化转换超表面加载的缝隙阵列天线。超表面采用渐变L型枝节的设计方法,其极化转换比大于0.9的工作带宽为79.2%。为缩减一款2×2的H形缝隙阵列天线的雷达散射截面(Radar Cross Section, RCS),将超表面结构加载到该天线上方。对阵列天线及超表面天线分别进行了仿真和测试,超表面天线的辐射特性保持良好,同时其RCS对于垂直入射方向上的x和y极化波分别在13.4～30.5 GHz和13.1～30.7 GHz得到10.0 dB的缩减。     

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。     

基于三频应用的混合谐振器天线设计

提出了一种新的适用于三频应用的混合谐振器天线。该天线辐射结构采用H型金属辐射片并加载矩形介质谐振器,形成混合型谐振器。同时提出一种新的混合馈电方式,使得介质谐振器产生双高阶模,最终形成可工作于三频段的混合型天线。经过优化设计,天线工作频率为1.45～1.63 GHz,3.62～4.1 GHz和4.55～5.86 GHz,其相对带宽分别为11.6%,12.4%和25.2%,天线实测结果表明了该设计的有效性。     

具有高隔离度的紧凑型三陷波UWB-MIMO天线设计

提出了一种具有高隔离度的紧凑型三陷波超宽带（ultra-wideband, UWB）多输入多输出（multiple-input multiple-output, MIMO）天线,整体尺寸为38 mm×26 mm×1.2 mm.通过对辐射贴片底部两侧进行多切角,实现了宽带化;通过在接地板上加载改进的波纹T型去耦结构,并刻蚀倒“π”型槽缝隙,实现了较高隔离度;通过在辐射贴片上刻蚀“U”型缝隙、在馈线上刻蚀类“H”型缝隙以及在右侧引入倒“C”型寄生枝节,实现了WiMAX(3.3～3.6 GHz)、WLAN(5.15～5.85 GHz)和X波段（7.25～7.75 GHz）3个频段的陷波.仿真与测试结果表明,该天线工作频段为2.9～11.3 GHz（相对带宽达到118.31%）,隔离度小于-22.6 dB,包络相关系数小于0.01,辐射效率高,辐射特性良好,可以广泛应用于无线通信系统领域中.     

基于单脊波导的缝隙阵列天线研究

采用理论分析和电磁仿真相结合的方法,详细分析了单脊波导中电磁场和表面电流的分布特点,并结合计算机辅助设计的方法,实现了一款工作于C波段单脊波导脊边双缝阵列天线.这种新型天线通过在单脊波导的脊边上成对开设倾斜缝隙来实现.仿真实验表明:本设计中天线的交叉极化降低到-50.26dB,而天线的横截面尺寸仅为同频段标准矩形波导的47%.     

串联邻近耦合馈电微带天线阵列的设计

针对高增益、高效率的微带天线需求,将邻近耦合馈电引入串馈微带阵列,提出两种串联谐振微带天线阵列设计。首先研制出1??16元低副瓣串联天线阵列,工作频率35 GHz,测试得到增益为17.3 dBi,带宽4.3%,副瓣电平-17.6 dB。在上述馈电方式中引入U型谐振器及馈电缝隙,提出一种串联邻近耦合馈电的双频正交极化天线阵列,中心频率分别为4.5 GHz和5.0 GHz,两个频带内带宽分别为5.0%和7.8%,隔离良好,中心频率处增益为7.6 dBi和8.2 dBi。这种馈电方式便于组成高效率的大阵列,同时具有良好带宽,在实现多功能共口径阵列中具有独特优势。     

60 GHz band radial line slot array antenna fed by rectangularwaveguide

A single-layered radial line slot array (SL-RLSA) antenna etched on a substrate and fed by a rectangular waveguide is presented in the 60 GHz band. The design curves are obtained by an efficient electromagnetic coupling analysis using Ewald sum technique and Shanks' transformation. The antenna has rectangular waveguide feed structure using a rectangular waveguide-to-radial line transition. The prototype antenna of 10 cm diameter was tested and the gain of 30 dBi was measured at 60 GHz     

Ultra-Wideband Slot Antenna with Rejection of WLAN and ITU Bands Using Protruded Strip Resonators

In this paper, a different method for designing a new slot antenna with dual band-notched characteristic for ultra-wideband applications is presented. The proposed antenna consists of a square-ring radiating stub with an inverted T-shaped strip protruded inside the ring, a feed-line with an E-shaped strip protruded inside the rectangular slot, and a ground plane with a pair of L-shaped strips protruded inside the extra rectangular slot. In this study, by using a a pair of L-shaped strips protruded inside the slot in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced. By using this modified structure in the ground plane, the antenna provides a wide usable fractional bandwidth of more than 130 % (3.01–15.35 GHz). To generate a single band-notched function, we convert a square radiating patch to a square-ring with an inverted T-shaped strip. Finally, by adding a rectangular slot with a protruded E-shaped strip in the microstrip feed line, a dual band-notched function is achieved. The measured results reveal that the presented dual band-notched slot antenna offers a very wide bandwidth with two notched bands, covering all the 5–6 GHz wireless local area network, 8–8.5 GHz international telecommunication union bands.     

Transverse slot antenna array in the broad wall of a rectangular waveguide partially filled with a dielectric slab

A compact and wide-band transverse slot antenna array in the broad wall of a rectangular waveguide partially filled with an H-plane -dielectric slab is presented in this paper. By partially filling an H-plane dielectric slab in the waveguide, the inter-element spacing between slots is reduced to be about 0.8 free-space wavelengths to avoid grating lobes. In addition, the partially filled material provides extra flexibility to adjust the slot impedance as desired within a relatively wide frequency range. A new feeding network is designed for this antenna array, which can prevent the shift in the pointing angle of the array's main radiation beam with the change of frequency. Experimental data for a 2/spl times/4 antenna array operating at X-band show that stable radiation pattern over a wide frequency range can be obtained. The measured gain is 16.9 dB at 10 GHz and the fluctuation is less than 2 dB over a frequency band of 1.5 GHz. The slot array's 10-dB return loss bandwidth is 13% and the cross-polarization level is better than -25 dB.     

Radial cavity-fed spatial power combiner with retrodirective array behavior

This paper discusses the design and operational properties of a circular array of slot coupled active GaAs metal-semiconductor field-effect transistor (MESFET) rectangular microstrip patch antennas arranged for quasioptical power combining at X band. The active antenna radiating elements are injection locked by slot coupling to a radial cavity waveguide. Spatial power combining efficiency of 75% and dc to radio frequency (RF) conversion efficiency of 10% at 28 dBm EIRP was achieved at 10.38 GHz. Retrodirective action was also demonstrated by using the active elements as self-oscillating mixers pumped at 20.76 GHz.     

Dielectric rod antenna based on image NRD guide coupled to rectangular waveguide

A dielectric rod antenna based on an image NRD guide fed by a slot in the broad wall of a rectangular waveguide is proposed. This configuration is developed for the use in the design of an array of this antenna. The antenna characteristics are investigated using the finite difference time domain (FDTD) technique. Measured results at 30 GHz band are presented to validate the numerical analysis.     

Enhanced‐Gain Planar Substrate‐Integrated Waveguide Cavity‐Backed Slot Antenna with Rectangular Slot Window on Superstrate

A novel substrate‐integrated waveguide (SIW) cavity‐backed slot antenna is proposed in this study to achieve enhanced‐gain performance. The peak gain is remarkably improved with the use of an SIW cavity and metallic superstrate. The superstrate comprises a single rectangular slot window and two half‐wavelength patches. The gain can be enhanced by combining the in‐phase radiating fields. Further, the 10 dB bandwidth of the proposed antenna ranges from 2.32 GHz to 2.49 GHz, which covers the wireless local area network band. The measured peak gain is 9.44 dBi at 2.42 GHz.     

A wideband high gain dielectric resonator antenna for RF energy harvesting application

A novel high gain and broadband hybrid dielectric resonator antenna (DRA) is designed and experimentally validated. To obtain the wide impedance bandwidth, the proposed antenna geometry combines the dielectric resonator antenna and an underlying slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of the slot and DRA. An inverted T-shaped feed line is used to excite both antennas, simultaneously. It supports amalgamation of different resonant modes of the both, DRA and slot antenna. The measured results show that the proposed antenna offers an impedance bandwidth of 120% from 1.67 to 6.7 GHz. The antenna gain is next enhanced by a reflector placed below the antenna at an optimum distance. On engineering the height and dimension of this reflector the antenna gain is improved from 2.2 dBi to 8.7 dBi at 1.7 GHz. Finally, antenna operation is attested experimentally with a rectifier circuit in the frequency range of 1.8–3.6 GHz, where various strong radio signals are freely available for RF energy harvesting. The measured maximum efficiency of the rectifier and rectenna circuit were found to be 74.4% and 61.4%, respectively.     

宽带单脊波导缝隙天线的设计

根据传输线方程推导了单脊波导辐射缝隙有源导纳的计算公式,结合三维电磁仿真软件HFSS提取了天线阵列中辐射缝隙的有源电导,设计了一个8元单脊波导缝隙线阵,实测结果表明,副瓣为-23.61dB,VSWR≤2时的相对带宽为8%,约为矩形波导缝隙天线的2倍。     

Circularly polarized dielectric-loaded planar antenna excited bythe parallel feeding waveguide network

A new receiving planar array antenna for DBS (direct broadcasting satellite) is proposed. The element antenna is a short waveguide aperture mounted in the ground plane, loaded with a dielectric and polarizers, and excited through its side wall by another feeding rectangular waveguide. The gain of the element antenna loaded with a dielectric is so high that the grating lobes can be reduced sufficiently even if the element spacing in the array is wider than the wavelength in free space. Therefore we can reduce the number of the array elements, and parallel feeding by the low loss waveguide network can be feasible to provide a planar array antenna. This paper describes the experimental results of several kinds of the circularly polarized dielectric-loaded element antennas and the planar antennas fed by the waveguide network. In the 12 GHz band the planar antenna with 64-element radiators has a maximum gain of 31.9 dBi with an aperture efficiency of 94.7%, the 1 dB-down frequency bandwidth of the gain is about 800 MHz (6.7% for a center frequency of 11.85 GHz), and the frequency bandwidth of the axial ratio is less than 1 dB of 850 MHz (7.2%)     

Numerical study of waveguide endwall slot feed microstrip arrays

An initial numerical study of a 4×4 microstrip array excited by a rectangular waveguide endwall slot is described. This design is a candidate for an LMDS subscriber equipment antenna. Direct coupling via a slot avoids the use of a probe, which prior investigators have shown to be detrimental to manufacturing yield at LMDS band. Tapering the short sides of the rectangular waveguide feed is shown to improve the input impedance matching here, with the optimal taper length being about λ_g/2. The input impedance bandwidth was 5.2%