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     

Low profile equilateral-triangular dielectric resonator antenna ofvery high permittivity

An aperture-coupled equilateral-triangular dielectric resonator antenna (DRA) of very high permittivity (ϵ_r=82) is investigated experimentally. The triangular DRA is more compact in size than rectangular and circular disk DRAs operating at the same frequency. The impedance matching, radiation patterns and antenna gain of the triangular DRA are presented     

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     

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.     

Broadband compact stacked T-shaped DRA with equilateral-triangle cross sections

A compact T-shaped dielectric resonator antenna (DRA) with two equilateral-triangle cross sections is investigated in this letter. The DRA is vertically placed on a finite ground plane and excited by a coaxial probe to provide broadband and conical radiation patterns. In order to examine the proposed design, simulations and measurements were employed to investigate the proposed antenna, and a good agreement between them was obtained. The proposed design produces an impedance bandwidth of more than 60% from 1.6 to 3.1GHz, which effectively covers several promising application bands in contemporary wireless communication systems, such as digital communication systems (DCS: 1710-1880MHz), personal communication systems (PCS: 1850-1990MHz), universal mobile telecommunication systems (UMTS: 1920-2170MHz), wireless local area networks (WLANs: 2.4-2.485GHz). Additionally, stable conical patterns were also obtained within the interest frequency band.     

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     

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...     

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.     

A theoretical and experimental investigation of annular, annular sector, and circular sector microstrip antennas

An analysis is presented for three related shapes of microstrip antenna elements: the annular; annular sector; and circular sector. The method of analysis involves the full expansion of resonant modes within the cavity formed by the radiating patch and the ground plane. Experimental results for representative radiators are also included for comparison.     

A Miniature Quadrifilar Helix Antenna for Global Positioning Satellite Reception

The design is described of a very compact quadrifilar helix antenna. A hollow ceramic rod is used as a dielectric load to reduce antenna size, which is only 2.7% of an air-loaded quadrifilar helix antenna. A simple equivalent circuit is established for the proposed quadrifilar helix antenna to demonstrate impedance characteristics. A self-phasing method for achieving circular polarization is also proposed. This method is convenient for tuning circular polarization. Additionally, a compact matching structure is designed to match the proposed antenna, which only utilizes short transmission-line sections and one capacitor. For experiments, the proposed antenna is designed at 1.575 GHz such that it can be utilized for global position system. Measurement and simulation results agree. A hemispherical pattern with a beamwidth of 150 $^{circ}$ is measured. This circular-polarized pattern with a wide beamwidth is feasible for mobile applications.      

Square-ring microstrip antenna with a cross strip for compactcircular polarization operation

A novel design of square-ring microstrip antenna with a cross strip for achieving compact circular polarization (CP) operation is proposed and experimentally studied. The cross strip can be placed in the centerlines or diagonals of the square-ring patch. Either design can make its excited fundamental mode patch surface current path much longer than that in a conventional square microstrip antenna with same antenna size. By incorporating a small tuning stub for splitting the fundamental mode into two near-degenerate resonant modes with equal amplitudes and 90° phase-difference compact CP operation for the proposed design can he obtained     

Compact annular-ring embedded circular patch antenna with cross-slot ground plane for circular polarisation

A compact circular patch antenna embedded in a narrow annular-ring which uses an unequal cross-slotted ground plane is presented. This new compact structure provides circular polarisation and is easily matched to 50 /spl Omega/ at the low frequency of operation. The size of the proposed antenna is reduced by over 55% compared to the conventional annular-ring CP patch antenna with a strip. The bandwidth and centre-frequency show weak dependence on the position of the feedpoint in the patch and demonstrate wider manufacturing tolerances. Good circularly polarised properties and wide bandwidth are obtained for the proposed compact antenna.     

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.     

Design of a vehicular antenna for GPS/Iridium using a geneticalgorithm

In this paper, we describe a vehicular wire antenna, designed using a genetic algorithm that may be used for both the GPS and Iridium systems. It has right-hand circular polarization, near hemispherical coverage, and operates over the frequency band from 1225 to 1625 MHz. This antenna was simulated using the numerical electromagnetics code (NEC) and then fabricated and tested. The antenna consists of five copper tubing segments connected in series, has an unusually odd shape, and is very inexpensive. It fits in a volume approximately 10 cm×10 cm×15 cm, The input voltage standing wave ratio (VSWR) and circular polarization radiation patterns were computed and measured. The VSWR was under 2.2 at the design frequencies of 1225, 1575, and 1625 MHz. The gain varied by less than 12 dB for a 170° sector; it generally fell off near the horizon so the variation was less for 150° and 160° sectors. This new design process, which uses a genetic algorithm in conjunction with an electromagnetics code, produces configurations that are unique and seem to outperform more conventional designs     

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.     

Multi-band hybrid antenna for ultra-thin mobile phone applications

A compact hybrid antenna consisting of two PIFAs and a slot antenna is proposed for ultra-thin mobile phone applications. The antenna has a very compact volume of 46 x 10 x 4.2 mm3, and it operates at GSM 850/900, DCS, PCS, and UMTS bands, simultaneously. Results show that its bandwidth and efficiency are sufficient for these penta-band mobile phone applications.     

Three orthogonal polarisation DRA-monopole ensemble

A dual feed HE/sub 11/spl delta// mode dielectric resonator antenna (DRA) loaded monopole antenna ensemble is described. The two antennas were unaffected by co-location, having coupling less than -25 dB at 2.33 GHz, making the ensemble capable of radiating all three orthogonal linear polarisations. The dielectric resonator antenna had an input impedance bandwidth of 1.9%, while the monopole gave 56%. This small volume ensemble antenna is suitable for mobile communications terminals.     

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.     

Feasibility of compact ranges for near-zone measurements

The purpose of this paper is to demonstrate the feasibility of using compact range reflector systems to make near-zone radiation or scattering measurements. This can be achieved by designing the compact range to provide a uniform spherical wave incident upon the antenna or scatterer under test. The basic design technique is demonstrated using the Scientific Atlanta reflector system which has been modified by adding an elliptic rolled edge to improve the uniformity of the incident wave. The near-zone range design is validated (from around 50 ft range to the far zone) by probing the field in the measurement volume and by comparing measured backscattering patterns from a circular cylinder with those calculated by the geometrical theory of diffraction (GTD). All the advantages of a conventional far-zone compact range are now made available by our demonstrated variable-zone (adjustable continuously from 50 ft to infinity) compact range.