Half volume dielectric resonator antenna designs

The authors demonstrate that the volume of a conventional dielectric resonator antenna (DRA) can be reduced by approximately half. The technique relies on employing an additional conducting plate in the DRA, which acts as an electric wall. Experimental and simulation results are provided for cylindrical and rectangular dielectric resonator antenna designs     

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.     

Broadband dielectric resonator antennas excited by L-shaped probe

Dielectric resonator antennas (DRAs) designed for broadband applications and excited by L-shaped probe are presented. The L-probe is housed under an air-filled groove between the DRA and the ground plane. A 32% matching bandwidth (S/sub 11/<-10 dB) is achieved with broadside radiation patterns. The new structure is constructed from the same dielectric materials. Thus, it is mechanically better than other wideband DRAs that consist of more than one dielectric material such as the stacked DRA. Some results are verified experimentally. The performance of this DRA and those fed by traditional probes and slots are investigated numerically. In addition, comparisons between L-probe excited DRAs and L-probe excited microstrip patch antennas are discussed.     

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     

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.     

Compact dielectric resonator antenna for WLAN applications

A new dielectric resonator antenna (DRA) with reduced size for WLAN applications is presented. The proposed antenna consists of a rectangular dielectric resonator with partial vertical and horizontal metallisations which is coupled to a microstrip line through a rectangular aperture in the ground plane. A 9.6 reduction coefficient is obtained compared to the volume of an equivalent isolated DRA. An experimental 12% bandwidth is also achieved in spite of the compact size.     

Perforated dielectric resonator antennas

A dielectric resonator antenna (DRA) is formed by perforating a dielectric substrate with a lattice of holes. The performance of several perforated DRA prototypes is compared to a conventional DRA and the results demonstrate better gain and cross-polarisation levels. This technique of fabricating DRAs using perforations is intended for array applications, eliminating the need to position and bond individual elements.     

Circularly polarized circular sector dielectric resonator antenna

A circular sector dielectric resonator antenna (DRA) with circular polarization and a single feed is investigated and demonstrated. The design utilizes the radius to height ratio and feed position of the circular sector DRA to excite two resonant modes that are spatially orthogonal in polarization and in phase quadrature. Experimental results are provided for the design and these demonstrate that the circular sector DRA produces circular polarized radiation with axial ratio less than 3 dB over a 10% bandwidth     

Novel Utilization of the Dielectric Resonator Antenna as an Oscillator Load

For the first time, the idea of using the dielectric resonator antenna (DRA) as an oscillator load, named as DRAO, is presented in this paper. Unlike the conventional dielectric resonator oscillator (DRO), where the DR was merely used as a resonator, the DR here serves as both the radiating and oscillating loads. In addition, a compact tri-function hollow DR that incorporates the packaging function to the above dual function is demonstrated. The design procedures of the dual- and tri-function DRAOs are discussed. For demonstration, the DRAOs are designed at 1.85 GHz, which is used in the popular personal communications system (PCS). The return losses, input impedances, antenna gains, signal spectrums, phase noise, and radiation patterns of the two DRAOs are presented. It is shown that the loaded Q_L factor of the DRA can be increased by internally embedding a compact metallic cavity to the DR. It is found that with a higher loaded Q_L factor, the phase noise of the antenna oscillator using the hollow DRA (tri-function DRAO) is better than that using a solid DRA (dual-function DRAO).     

Circularly polarised dielectric resonator antenna with metallicstrip

A new design of circularly polarised slot fed dielectric resonator antenna (DRA) is presented. The dissymmetry of the design enabling circular polarisation relies on a metallic strip printed on top of the resonator. Simulations are compared with measurements for a single antenna as well as a four DRA sequential rotation array     

Experimental study of wideband hybrid dielectric resonator antenna on small ground plane

A wideband hybrid dielectric resonator antenna (DRA) is investigated experimentally. The proposed hybrid DRA comprises a rectangular dielectric resonator and a conductor-backed coplanar waveguide (CB-CPW) slot etched on a small ground plane. Dual resonances of the two radiators are merged to expand the antenna bandwidth. By utilising the CB-CPW structure, a back-cavity is formed underneath the slot to suppress the backward radiation. Hence consistent unidirectional radiation pattern is achieved across the matching band.     

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   

一种适用于波束扫描的宽带低剖面介质谐振器天线

近年来,为解决传统介质谐振器天线（dielectric resonator antenna, DRA）体积庞大等问题,新颖的低剖面DRA如介质贴片天线和平面介质天线被提出并迅速成为研究热点.然而,现有的低剖面DRA设计要么平面尺寸较大（>0.5λ0×0.5λ0）,要么带宽较窄（<10%）,限制了它们的实际应用.文中提出了一种具有小型化平面尺寸的宽带低剖面DRA.本天线采用介质贴片设计,顶部为高介电常数的介质贴片,中间为低介电常数的介质基板,底部为缝隙馈电结构.缝隙馈电结构可激励起介质贴片谐振器的基模TE111和高次模TE131两种工作模式,这两种模式的场分布在贴片边缘部分存在基模场强较弱而高次模场强较强的显著区别.本设计巧妙地利用了该区域的模式场强区别,通过略微增加贴片边缘部分高度来显著影响高次模谐振频率而轻微影响基模谐振频率,从而将高次模TE131的谐振频率迅速下拉并与基模TE111的谐振频率靠近合并,在不增大介质贴片平面尺寸的前提条件下获得宽带工作效果.本天线的三维尺寸为0.35λ0×0.35λ0×0.08λ0 (λ0为中心频率处的空气中波长),线极化实物案例测试结果表...     

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.     

Reflectarray element based on strip-loaded dielectric resonator antenna

A new low-loss reflectarray element based on a dielectric resonator antenna (DRA) loaded with a metallic strip etched on the top of the DRA is presented. The strip behaves as a parasitic element, and by adjusting its length, the desired reflected phase is achieved. A set of DRA samples were fabricated and measured in C-band. A low loss (less than 0.9 dB) is demonstrated when the phase is varied. It is also shown that the loss is much higher (up to 5 dB) when the strip is directly printed on a dielectric substrate with the same characteristics.     

Excitation of dielectric resonator antenna using a soldered-throughprobe

A soldered-through probe is used to excite the dielectric resonator antenna (DRA). A cylindrical ring DRA is used to demonstrate the feasibility of this excitation method. The return loss, radiation pattern, and antenna gain of the new configuration are studied     

Ultra wideband (UWB) dielectric resonator antenna using fractal-inspired feeding mechanism

This article examines a compact dielectric resonator antenna (DRA) for UWB applications. Here a composite feeding structure excites a dielectric resonator which in tern provides the resonant modes TE₁₁₁, TE₁₂₁, TE₂₁₂, and TE₂₂₂. The dielectric resonator (DR), built of alumina ceramic (ε_{r, DR} = 9.8), is mounted on a fractal triangular patch, inspired by Sierpinski Gasket. The suggested DRA is supported by a FR4 substrate (ε_{r, sub} = 4.4) and measures compactly 40 × 30 × 8.5 mm³. To confirm the results of its simulations, the proposed antenna's prototype is prepared and measured up to the second iteration. The measured outcome demonstrates that the suggested antenna has a frequency range of 3.38–10.71 GHz (104%) for S₁₁ < −10 dB and provides a maximum gain of 7.23 dBi at 8 GHz along with highest possible simulated efficiency of 98%. The suggested DRA is appropriate for small-range future 4G/5G UWB wireless multimedia applications due to its ultrawide bandwidth, excellent gain, reasonable efficiency, omnidirectional radiation features, and compact construction. This DRA is also suitable for repeaters of mobile and vehicular communications.     

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.     

Excitation of dielectric resonator antennas by a waveguide probe: modeling technique and wide-band design

Analysis of a dielectric resonator antenna (DRA) fed by a waveguide probe is presented. The probe is excited by the dominant mode of a waveguide and extends into the DRA through an aperture in the waveguide wall. The DRA has, in general, an arbitrary shape and resides on an infinite ground plane, which coincides with the exterior of the waveguide broad wall. A simple and efficient analysis procedure is implemented where the problem is divided into two parts. In the upper part, the input impedance of the DRA excited by a coaxial probe is obtained with respect to the feeding position on the ground plane independent of the waveguide part. Then the input impedance is transformed to the waveguide part as a concentrated load at the end of the probe connected to the waveguide wall. The effect of the wall thickness is taken into account by modeling the section of the probe passing through the waveguide wall as a coaxial cable transmission line supporting the transverse electromagnetic mode. Thus the DRA input impedance is transferred from the ground plane reference to the waveguide inner wall reference. Results obtained using the method of moments are compared with those obtained using the finite-difference time-domain method and exhibit very good agreement. The procedure is used to achieve a bandwidth of 50% for a stacked DRA excited by a waveguide probe.     

Two-element endfire dielectric resonator antenna array

The radiation from a two-element endfire dielectric resonator antenna array has been experimentally investigated and compared with theoretical formulations. The measured gain of the array is 4.6, which is 35% higher than the gain of a single element DRA. The measured impedance bandwidth is 11.4%, which is 0.7% lower than the bandwidth of the single element DRA. Good agreement has been observed between the predicted and measured results