Study on Sequential Feeding Networks for Subarrays of Circularly Polarized Elliptical Dielectric Resonator Antenna

Circularly polarized (CP) dielectric resonator antenna (DRA) subarrays have been numerically studied and experimentally verified. Elliptical CP DRA is used as the antenna element, which is excited by either a narrow slot or a probe. The elements are arranged in a 2 by 2 subarray configuration and are excited sequentially. In order to optimize the CP bandwidth, wideband feeding networks have been designed. Three different types of feeding network are studied; they are parallel feeding network, series feeding network and hybrid ring feeding network. For the CP DRA subarray with hybrid ring feeding network, the impedance matching bandwidth (S₁₁<-10 dB) and 3-dB AR bandwidth achieved are 44% and 26% respectively     

The slot-coupled hemispherical dielectric resonator antenna with a parasitic patch: applications to the circularly polarized antenna and wide-band antenna

The aperture-coupled hemispherical dielectric resonator antenna (DRA) with a parasitic patch is studied rigorously. Using the Green's function approach, integral equations for the unknown patch and slot currents are formulated and solved using the method of moments. The theory is utilized to design a circularly polarized (CP) DRA and a wide-band linearly polarized (LP) DRA. In the former, the CP frequency and axial ratio (AR) can easily be controlled by the patch location and patch size, respectively, with the impedance matched by varying the slot length and microstrip stub length. It is important that the AR will not be affected when the input impedance is tuned, and the CP design is therefore greatly facilitated. For the wide-band LP antenna, a maximum bandwidth of 22% can be obtained, which is much wider than the previous bandwidth of 7.5% with no parasitic patches. Finally, the frequency-tuning characteristics of the proposed antenna are discussed. Since the parasitic patch can be applied to any DRAs, the method will find applications in practical DRA designs.     

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.     

Performance Analysis of a Low Profile Hybrid Antenna for Broadband Applications

In this paper, a low profile dielectric resonator antenna (DRA) is proposed and investigated. To achieve the broad impedance bandwidth the proposed antenna geometry combines the dielectric resonator antenna and an underlying microstrip-fed slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of slot and DRA. The physical insight gained by the detailed parametric study has led to find out a set of guidelines for designing the antennas for any particular frequency band. The design guidelines have been verified by simulating a set of antennas designed for different frequency bands. For validation, a prototype antenna is fabricated and tested experimentally. The measured results show that the proposed DRA offers an impedance bandwidth of about \(125.34\%\) from 1.17 to 5.1 GHz with reasonable gain between 3.5 and 5.7 dBi. The volume of the proposed DRA is \(0.16\lambda _{dr}^{3}\), where \(\lambda _{dr}\) is the wavelength at center operating frequency of the DR. A comprehensive study on bandwidth shows that the proposed DRA provides maximum bandwidth in terms of the DR volume (\(\hbox {BW}/V_{dr}\)) and the DR height (\(\hbox {BW}/h_{dr}\)) than the other similar reported work on hybrid wideband DRA designs.     

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.     

Circular Polarization Dielectric Resonator Antenna Excited by Single Loop Feed

A new feeding method for the circular polarization (CP) dielectric resonator antenna (DRA) is proposed in this letter. Two orthogonal modes (TE^x_δ11, TE^y_1δ1,) of the rectangular DRA are excited by a 90° phase difference of the differential and common modes currents of the proposed feeding structure. To demonstrate the good CP performance of the proposed method, a right‐hand CP DRA for a global positioning system was designed. The impedance bandwidth of the proposed antenna for S₁₁相似文献   

基于介质片加载实现MIMO介质谐振器天线解耦

提出了一种通过在介质谐振器(DR)上表面侧边加载介质片(DS)来实现1×2 MIMO介质谐振器天线(DRA)解耦的新方法。1×2 MIMO DRA采用双层介质基板结构以优化阻抗匹配特性和辐射特性,两DR的边到边间距为0,天线工作在毫米波频段。所加载的DS使得DR内的场重新分布并向DS加载区域以及DS内集中,从而减弱耦合到另一DR单元的场强以实现解耦效果。基于ANSYS HFSS的仿真结果表明天线的-10 dB阻抗匹配带宽为25.6%(22.75～29.43 GHz),带内最大实现了30 dB的隔离度的增强。     

Development of a Cavity-Backed Broadband Circularly Polarized Slot/Strip Loop Antenna With a Simple Feeding Structure

A cavity-backed loop antenna is developed for producing broadband circularly polarized (CP) radiation. The antenna configuration consists of a slot loop and a strip loop. The slot loop radiates a CP wave at a lower frequency while the strip loop produces CP radiation at a higher frequency. A combination of the two frequencies leads to a bandwidth enhancement. The slot/strip loop antenna is fed by a single straight microstrip line. It is demonstrated that the cavity-backed slot/strip loop antenna can achieve an axial ratio (les 3 dB) bandwidth of 19% with good impedance matching. The antenna configuration is described and the operating principles for broadband circular polarization and impedance matching are analyzed. The antenna performance is confirmed by experimental results.     

Design and Optimization of Dual Band Microstrip Antenna Using Particle Swarm Optimization Technique

Dual-frequency operation of antenna has become a necessity for many applications in recent wireless communication systems, such as GPS, GSM services each operating at two different frequency bands. A new technique to achieve dual band operation from different types of microstrip antennas is presented here. An evolutionary design process using a particle swarm optimization (PSO) algorithm in conjunction with the method of moments (MoM) is employed effectively to obtain the geometric parameters of the antenna performance. In this article a PSO based on IE3D®? method is used to design dual band inset feed microstrip antenna. Maximum return loss is obtained at 2.4 GHz is ?43.95 dB and at 3.08 GHz is ?27.4 dB. Its bandwidth, of 33.54 MHz, ranges from 2.38355 GHz to 2.41709 GHz. Simulated and experimental results of the antenna are discussed.     

Dual band dielectric resonator antenna for wireless application

The proposed technique is an integration of a slot antenna and a dielectric resonator antenna (DRA). This is designed without compromising miniaturisation and efficiency. It is observed that the integration of slot and dielectric structure itself may be merged to achieve extremely wide bandwidth over which the antenna polarisation and radiation pattern are preserved. Here the effect of slot size on the radiation performance of the DRA is studied. The antenna structure is simulated using the CST software. The simulated results are presented and compared with the measured result. This DRA has a gain of 7.1 and 6.3?dBi at 5.7 and 8.1?GHz, respectively, its 10?dB return impedance bandwidth of nearly 4.5% and 5.5% at two resonating frequencies. A total of 98% efficiency has been achieved from the configuration. It is shown that the size of the slot can significantly affect the radiation properties of the DRA and there are good agreements between simulation and measured results.     

Strip-fed rectangular dielectric resonator antennas with/without a parasitic patch

A rectangular dielectric resonator antenna (DRA) was studied theoretically and experimentally. The rectangular DRA is excited by a strip, which is compatible with a coaxial probe. Both linearly polarized (LP) and circularly polarized (CP) fields of the antenna are considered. In previous studies of the LP rectangular DRA, only the fundamental TE/sub 111/ mode has received much attention. In this paper, it is found that the fundamental TE/sub 111/ mode, together with the higher-order TE/sub 113/ mode, can be used to design a wide-band LP DRA. The bandwidth of the dual-mode DRA can be over 40% for a conventional rectangular DRA with a simple feed. For the CP mode, a parasitic patch is attached on a side wall of the DRA to excite a degenerate mode. In both the LP and CP cases, the finite-difference time-domain (FDTD) method is used to analyze the problems. The results agree reasonably with measurements.     

Cross-T-shaped dielectric resonator antenna for wideband applications

A new dielectric resonator antenna (DRA) is introduced for wideband applications, where the wideband of this DRA design comes from three factors: a compact cross-T-shaped dielectric resonator, a conformal inverted-trapezoid patch as a feed mechanism, and a copper-clad substrate as a baseboard. Measured results demonstrate that the proposed DRA achieves an impedance bandwidth of about 71.8% for VSWR les 2, covering a frequency range from 3.56 to 7.57 GHz. This antenna also provides a stable broadside radiation pattern and a gain range of 3.2-7.3 dBi across the operating bandwidth.     

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.     

一种小型陷波多用途超宽带天线

提出了一种小型陷波多用途超宽带微带天线。该天线与一般的宽缝隙微带天线类似,通过在矩形调谐支节上开V形缝隙获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.4到11GHz频段内驻波比小于2,在5.15~5.95 GHz范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

An X-band dielectric resonator antenna using a single elliptical shaped dielectric resonator

This paper presents design evolution of a single elliptical dielectric resonator antenna to achieve wide measured impedance band-width extending from 8.26 GHz to 12.15 GHz. Design evolved from a right circular cylindrical DRA by varying the dimension along the semi-minor axis and thereby resulting in an elliptical DRA that supports near similar field distribution over the X-band. This similar field variation is achieved by tuning the eccentricity of the elliptical geometry, the feed position as well as height of the DRA. A fabricated prototype is developed and measured results agree well with that obtained from simulation. Apart from wide impedance bandwidth, the observed pattern bandwidth is also similar.     

多用途陷波小型超宽带天线

提出了一种具有陷波特性的多用途小型超宽带微带天线。该天线类似一般的宽缝隙微带天线,但在矩形调谐支节内嵌入T形支节获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.39～12GHz的频段内驻波比小于2,其中的5.15～5.95GHz的范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

Double stub microstrip fed two element Rectangular Dielectric Resonator Antenna for multiband operation

This article presents a design of multiband Rectangular Dielectric Resonator Antenna (RDRA) using two elements with different aspect ratio. The proposed DRA is excited by means of micro-strip feedline with double stubs which not only improves the bandwidth of each band but also achieves good impedance matching. The proposed DRA operates at “C” band, “WLAN” and “X” band frequencies and yields wide bandwidth of about 6.5%, 13.5% and 17.4% respectively. Two Rectangular DRs of completely different aspect ratio and double stub microstrip feeding achieve this multiband operation. The designed antenna is very compact and has a volume of 1737 mm³ only. It provides stable radiation patterns in all the three bands and has a maximum gain of 6.35 dBi with radiation efficiency of more than 82% over the operating band of frequencies. The proposed antenna has been studied, analyzed and optimized using Ansoft HFSS simulation software. The designed antenna is fabricated, tested and compared with other multiband designs. Good agreement is achieved between simulated and measured ones.     

一种新型高增益宽带圆极化天线阵列的设计

分析了一种具有高增益的宽带圆极化天线。每一个单元都是双面印刷偶极子,为了展宽带宽,采用了宽频带90°巴伦作为馈电网络用于给偶极子阵列馈电。在此基础上,制作了一个2×3 元小型圆极化平面阵,为了压缩尺寸,将馈电网络位于介质板的底层,该天线最高增益可以达到14.2dBi,并可以获得64%（VSWR<2）的阻抗带宽和54.5%（AR<3） 的轴比带宽。     

一种宽频圆极化H 形缝耦合微带天线设计

设计了一种具有较低背向辐射的宽频带圆极化口径耦合微带天线。在口径耦合单元的馈线上附加一对寄生微带线枝节来阻抗匹配,以实现宽频带;利用H 形口径耦合,减小贴片单元的后向辐射,提高天线效率;用威尔金森功分器移相器,使得两口径耦合馈电端口的正交电场相位差90°,从而获得圆极化波辐射。对提出的天线进行仿真及优化设计,最终天线获得了42.8%的阻抗带宽（VSWR＜2）,在30%带宽内获得了良好的圆极化性能（轴比＜2dB;特别在1200MHz~1540MHz带宽内,具有最优的综合性能,具有6dBi 以上的增益、20dB 以上的前后比和交叉极化鉴别率。     

一种新型环状宽带圆极化微带天线设计

本文设计了一种新型的环状开缝的宽带圆极化微带贴片天线,通过等幅度90°相位差的L型探针馈电。通过在环状贴片上开槽可以有效的增加轴比和阻抗带宽。传统的圆极化天线带宽受限于阻抗、轴比和增益的公共带宽,本文提出的天线得到有效带宽从1.1GHz到1.9GHz,相对带宽达到了53%以上,频带覆盖了GPS、GALILEO、COMPASS、GLONASS四大导航系统。该天线性能较好,加工调试简便,在卫星导航等领域具有广阔的应用前景。