New Half-Hemispherical Dielectric Resonator Antenna for Broadband Monopole-Type Radiation

A new half-hemispherical dielectric resonator antenna (h-HDRA) is proposed and a two-element h-HDRA configuration is employed to design a broadband monopole-type radiator. Two half sections of a hemispherical DRA are employed to enhance the impedance bandwidth by introducing an additional resonant mode. Since the new geometry of an h-HDRA is studied here for the first time, it is characterized using simulation and experimental studies. Two closely spaced resonant modes, which in a two-element h-HDRA generate monopole-type radiation are investigated. Results for both the single and two-element h-HDRAs are presented. As much as 35% impedance bandwidth (S₁₁<-10dB) with more than 5 dBi peak gain, 99.08% efficiency and monopole-type radiation pattern has been demonstrated using a prototype occupying a compact volume measuring 0.48lambda₀ by 0.2lambda₀ approximately, lambda₀ being the wave length corresponding to the center of the impedance bandwidth     

一种宽频带介质谐振器天线的设计与实现

摘 要：带宽拓展,一直以来是介质谐振器天线研究重要内容之一。基于此,本文设计了一款宽频带介质谐振器天线。采用共面波导馈电的单极天线与介质谐振器天线的混合结构,通过调节谐振器尺寸和共面波导的结构,使各个工作模式的频带互相重叠,展宽所设计天线的带宽;同时地板上引入开槽技术,对馈线进行阻抗匹配。利用仿真软件对天线参数进行优化仿真,实现天线频带宽度为2.98-7.18GHz（S11<-10dB）,相对带宽达到84.3%,带内最大增益达到4.9dBi。对该天线进行加工测试,仿真与测试基本吻合,结果表明,该天线不仅可实现宽频带,且结构简单,尺寸小,易集成,可广泛应用于WLAN/WIMAX等通信领域。     

The Trapezoidal Dielectric Resonator Antenna

The operational concepts of the trapezoidal dielectric resonator antennas (DRAs) are presented and their performance is studied theoretically and experimentally. The rectangular parallelepiped is a special case of the more general trapezoid and therefore a comparison between both is useful in order to highlight their similarities and differences. It is shown in this paper that the inverted trapezoidal DRA exhibits a significantly larger impedance bandwidth than the rectangular parallelepiped, while the rest of their properties remain similar. Based on that, two versions of a probe-fed wide-band linearly polarized (LP) DRA are designed by combing the resonances of the first two lower-order modes of the trapezoidal DRA. The resulting impedance bandwidth exceeds 55% $(S _{11} ≪ -10~{rm dB})$ and the patterns are broadside with low cross-polarization. The antennas are simple to fabricate and they can be easily made to be mechanically stable. The numerical analysis was performed with a commercially available FEM solver and an in-house developed finite-volume-time-domain (FVTD) code. The measurements confirmed the results of the simulations.      

Dielectric Patch Resonator and Antenna

This paper presents an overview of dielectric patch(DP) antennas developed in recent years.The employed DP resonator composed of a DP and a bottom substrate is analyzed comprehensively here,enabling the easy realization of a quasi-planar DP antenna. It combines the dual advantages of the conventional microstrip patch(MP) antenna and dielectric resonator(DR) antenna in terms of profile, gain,bandwidth, radiation efficiency, and design freedom.Furthermore, the DP antenna inherits the multi-mode ch...     

Broadband,High Gain,Narrow Width Rectangular Dielectric Resonator Antenna with Air Gap

The broadband, narrow width, rectangular dielectric resonator antenna (RDRA) of aluminum nitride (ε_r=8.6) was designed and the effect of inclusion of air gap at the bottom of the dielectric resonator antenna (DRA), above the ground plane, was investigated. Gain around 7 dBi was obtained for DRA with air gap (DRAAG) over a broad bandwidth in upper X, K_u, and K bands. Further enhancement in gain could be obtained by placing a metal wall parallel to the length of DRA. However, due to the presence of metal wall, bandwidth was reduced. These structures with the metal wall are capable of operating over a wide band extending from K_u band to lower K band with the gain of around 10 dBi. CST Microwave Studio Software was used to simulate all these structures. Performance parameters of DRA with air gap were compared with several broadband DRA structures reported in recent literature. The proposed DRAAG with the metal wall in this paper is capable of operating over a wide bandwidth along with a significant gain.     

微带馈电的圆柱形介质谐振器天线阵

提出了一种新型的圆柱形介质谐振器天线单元及其阵列设计.天线单元采用带有十字枝节终端的微带线进行馈电,在高介电常数的情况下,通过调节十字形终端枝节的设计和相对位置,获得较宽的阻抗带宽.基于此单元设计,研制了一个2×2元圆柱形介质谐振器天线阵,获得了4.2%的实测阻抗带宽和约11dBi的仿真增益.     

Wideband Circularly Polarized Dielectric Resonator Antenna

A circularly polarized quadruple strip feed cylindrical dielectric resonator antenna utilizing a pair of 90deg hybrid couplers is investigated experimentally. The antenna is shown to deliver an impedance bandwidth (S₁₁ < -10 dB) of 34.5%, from 1.75 to 2.48 GHz, and an axial-ratio bandwidth (AR < 3 dB) of 25.9%, from 1.65 to 2.14 GHz. The gain and radiation patterns are found to be stable within the passband.     

Rigorous Analysis of Rectangular Dielectric Resonator Antenna With a Finite Ground Plane

A probe-fed rectangular dielectric resonator antenna (RDRA) placed on a finite ground plane is numerically investigated using method of moments (MoM). The whole structure of the antenna is exactly modeled in our simulation. The feed probe, coaxial cable and ground plane are modeled as surface electric currents, while the dielectric resonator (DR) and the internal dielectric of coaxial cable is modeled as volume polarization currents. Each of the objects is treated as a set of combined field integral equations. The associated couplings are then formulated with sets of integral equations. The coupled integral equations are solved using MoM in spatial domain. The effects of ground plane size, air gap between dielectric resonator and ground plane, probe length, and position on the radiation performance of the antenna including resonant frequency, input impedance, radiation patterns, and bandwidth are investigated. The results obtained for the antenna parameters based on the MoM investigation shows that there is a close agreement with those obtained by measurement. Moreover it is shown that the MoM results are more accurate than other simulation results using software package such as High Frequency Structure Simulator (HFSS).      

Design and Development of Enhanced Gain Aperture Coupled Broadband Biodegradable Dielectric Resonator Antenna for WLAN Applications

Wireless Personal Communications - Metamaterial loaded star-shaped dielectric resonator antenna (SDRA) fed by aperture-coupled mechanism is used for the enhancement of bandwidth and gain. The...     

On the Differentially Fed Rectangular Dielectric Resonator Antenna

A differentially fed rectangular dielectric resonator antenna (DRA) is studied using the finite-difference time-domain (FDTD) method. The fundamental TE₁₁₁ mode of the rectangular DRA is excited at 2.4 GHz, with a 10-dB differential impedance bandwidth (|S_dd11| < -10 dB) of ~10.4%. To verify the theory, measurements were carried out, and reasonable agreement between theory and experiment is obtained. The effects of the magnitude and phase imbalances on the DRA impedance and radiation pattern are investigated.     

Bandwidth Enhancement of Circularly Polarized Dielectric Resonator Antenna

Axial‐ratio (AR) bandwidth enhancement is achieved for a circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) using a wideband hybrid coupler (WHC) combined with dual probe feed. The presented WHC, comprised of a Wilkinson power divider and a wideband 90° shifter, delivers good characteristics in terms of 3 dB power splitting and consistent 90° (±5°) phase shifting over a wide bandwidth. In turn, the proposed CP DRA, for the employment of the WHC, in place of conventional designs, provides a significant enhancement on AR bandwidth and impedance matching. The antenna prototype with the WHC exhibits a 3 dB AR bandwidth of 48.66%, an impedance bandwidth of 52.5% for voltage standing wave ratio (VSWR) ≤ 2, and a bandwidth of 44.66% for a gain of no less than 3 dBi. Experiments demonstrate that the proposed WHC is suitable for broadband CP DRA design.     

一种偏向辐射的介质谐振器天线设计

研究介绍了一种偏向辐射的介质谐振器天线设计方法.基于探针馈电圆柱形介质谐振器天线,在偏离馈电一侧对介质谐振器进行穿孔,并进行金属孔化.通过分析优化穿孔的大小与位置,实现了圆柱形介质谐振器天线的偏向辐射.仿真与实验吻合较好,结果表明:天线的10 dB相对阻抗带宽为7％,覆盖频率范围6.3～6.7 GHz,在阻抗带宽内,偏向辐射角度稳定在36°～37°,天线增益为6.0～7.2 dBi.     

Offset Cross-Slot-Coupled Dielectric Resonator Antenna for Circular Polarization

A cross-slot-coupled cylindrical dielectric resonator antenna (DRA) is studied theoretically and experimentally. In previous papers, a cross-slot of unequal slot lengths was centered under the dielectric resonator (DR), resulting in circular polarized operation of the antenna. In the present study, the design is enhanced by setting the centers of the two slots at different positions and taking into consideration the partial independence of the slot modes from the DRA mode. Thus, circular polarization (CP) bandwidth of up to 4.7% is attained experimentally in the broadside direction. It is also shown that a largely asymmetrical structure results in a very high bandwidth, but with the tradeoff of distorted CP operation off-broadside.     

圆极化倾斜波束介质谐振天线设计

基于非对称结构设计思想,以表面倾斜的高介电常数介质谐振器为辐射单元,采用改进的正交不等长缝隙结构耦合馈电,设计制作了一种圆极化倾斜波束介质谐振天线。通过对介质谐振器表面倾斜角度和馈电缝隙的参数优化,扩展了天线的频带宽度,实现了宽频带圆极化倾斜波束辐射。仿真结果表明:天线在同时满足S11<-10 d B、3 d B轴比和30°波束倾斜条件下的带宽为18.2%。同时,由于采用高介电常数介质谐振器,天线剖面高度降低到0.165λ。实测结果和仿真结果吻合较好,验证了该设计的有效性。     

超宽带单极子加载介质谐振器天线的设计

该文设计了一种尺寸小,频带宽,结构简单的单极子陶瓷介质谐振器天线。在单极子天线周围加载一个环形的陶瓷介质谐振器,利用环形谐振器与单极子谐振频率之间耦合来展宽频带。利用仿真软件HFSS建立天线的模型,并对模型进行优化仿真,得到了最佳的天线设计参数,仿真得到的天线频带宽度为0.7～4.6GHz,相对带宽达到了153%,使用矢量网络分析仪对该天线进行测量,实测结果与仿真值基本吻合。     

Aperture Coupled Rectangular Dielectric Resonator Antenna Array Fed by Dielectric Image Guide

This paper presents the design of a rectangular dielectric resonator antenna array coupled to narrow slot apertures that are fed by dielectric image guide (DIG). The DIG is excited by an X-band rectangular waveguide through a waveguide transition, and DIG tapering is used to match between the waveguide and the DIG. Reflection cancelling slots are added near the original slots to improve impedance matching. Since the slots radiate in both directions, a reflecting conducting plate is inserted above the DIG to decrease the back radiation of the antenna. The antenna is fabricated and the measured results are compared to the simulated results.      

Design and Analysis of Circularly Polarized Dielectric Resonator Antenna

Wireless Personal Communications - The paper presents a novel method for the improvement in the bandwidths by mode merging of the circularly polarized dielectric resonator antenna (CPDRA). The...     

一种新型宽带圆极化介质谐振器天线设计与实现*

设计了一种宽带圆极化介质谐振器天线,为一种鼠笼形的宽带一分四90毅相移功分微带馈电网络,采用缝隙耦合对介质谐振器顺序旋转耦合馈电。天线结构紧凑、加工简单,仿真和实测结果吻合良好,其阻抗带宽和低于3dB的轴比带宽重叠部分在1.09 GHz-1.83GHz、为50.7%。增益大于3dB 及轴比小于3dB 的波束宽度均达到90°。天线工作频率覆盖四大导航系统,包括中国的北斗系统、美国的GPS 系统、欧洲的伽利略(GALTLEO)系统和俄罗斯的格洛纳斯(GLONASS )系统的频段,天线可应用于全球卫星导航定位系统和无线宽带通信系统中。     

Four-Element Cylindrical Dielectric Resonator Antenna for Wideband Monopole-Like Radiation

A new four-element cylindrical dielectric resonator (CDR) array is proposed as a wideband low profile monopole-like antenna. Unlike previous investigations, the present antenna is easy to design and excite as it employs the dominant$ HEM_11delta$mode in each CDR. Ansoft's HFSS based design data and experimental results are presented. As much as 29% matching bandwidth$( S_11≪-10 dB)$with monopole-like radiation pattern over the entire band has been achieved with 4 dBi peak gain from a prototype occupying a very compact space measuring$0.6lambda_0$by 0.1$lambda_0$approximately.     

Broadband Microstrip Antenna With Left-Handed Metamaterials

A novel type of microstrip antenna is proposed for compact wideband wireless applications. The antenna is composed of six unit cells of left-handed metamaterial (LHM) and a dipole element. The dipole is directly connected to three of six LHM unit cells, which are arranged in a 2 $times$ 3 antenna array form. In this aspect, the proposed antenna is regarded as LHM loaded dipole antenna. The antenna is matched with a stepped impedance transformer and rectangular slot in the truncated ground plane. The coupled LH resonances and simultaneous excitation of different sections of unit cells and dipole result into broad bandwidth. The proposed antenna has a maximum gain of $-$1 dBi at 2.5 GHz. The measured return loss indicates 63% bandwidth for $vert{rm S}11vert≪-10 {rm dB}$ over the band of 1.3–2.5 GHz. The overall size of LHM loaded antenna is $lambda_{0}/2.87timeslambda_{0}/11.27timeslambda_{0}/315.80$ at the center frequency. The radiation of the electrically small LHM unit cells is also demonstrated by the simulated radiation pattern, which is an important concept for the antenna miniaturization.