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。     

Stacked annular ring dielectric resonator antenna excited byaxi-symmetric coaxial probe

A stacked annular ring dielectric resonator (DR) antenna composed of commercially available dielectric resonators and exited by axi-symmetric coaxial probe is studied computationally using the finite-difference time-domain (FDTD) method. The numerical results are checked against experimental measurements, and good agreement is observed. It is demonstrated that the introduction of air-gaps between the two DR's and also between the driven DR and the ground plane can improve the impedance bandwidth of the antenna significantly. The effects of the air-gaps thickness on the return loss and the bandwidth are discussed. The far-fields are also calculated by applying the electromagnetic field equivalence principle. The antenna produces an end-fire radiation field similar to that of an electric monopole     

FDTD analysis of probe-fed cylindrical dielectric resonator antenna

The finite-difference time-domain (FDTD) method is employed to analyze a probe-fed cylindrical dielectric resonator antenna. Numerical results for the input impedance and radiation patterns of the dielectric resonator (DR) antenna operating in HEM_11δ mode are presented and compare favorably with measurements. The effects of various parameters on the characteristics of the DR antenna are studied. Fabrication imperfection effects and the cross-polarization characteristics of this type of DR antenna are also investigated for the first time     

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.     

Ultra‐small Marker Beacon Antenna with a Wide Frequency Tuneable Capacitive Plate

In this paper, an ultra‐small marker beacon antenna operated in the VHF‐band is proposed. This antenna has a modified linear IFA structure with a lumped capacitor and a capacitive plate for frequency tuning and impedance matching. The capacitive plate is directly connected to the end of a linear radiator and is separated from the antenna ground by 1 mm. The main operating frequency is mainly controlled by the size and dielectric constant of the capacitive plate. The lumped capacitor is useful for fine frequency tuning. Using the proposed structure, an ultra‐small marker beacon antenna can be realized with a length of 0.04 λ₀.     

FDTD analysis of probe-fed cylindrical dielectric resonator antennaoperating in fundamental broadside mode

An analysis of a cylindrical dielectric resonator antenna operating at the fundamental broadside mode using the finite-difference time-domain (FDTD) method is presented. Good agreement between theoretical and experimental results on the input impedance of the DR antenna is obtained. The effects of the probe length, feed position and the dielectric constant on the input impedance are presented     

Input impedance of aperture coupled hemispherical dielectric resonator antenna

A hemispherical dielectric resonator (DR) antenna fed by a microstripline through an aperture on the ground plane is investigated both theoretically and experimentally. The broadside TE/sub 111/ mode input impedance of the antenna configuration is evaluated, and reasonable agreement between theory and experiment is obtained. The effects of the slot length and the slot width on the input impedance are studied and discussed.<>     

Theory and experiment of a coaxial probe fed hemisphericaldielectric resonator antenna

A hemispherical dielectric resonator antenna fed by a coaxial probe is studied both theoretically and experimentally. The Green's function for the evaluation of the input impedance is derived rigorously and expressed in a form convenient for numerical computations. The method of moments is used to obtain the probe current from which the input impedance of the DR antenna is calculated. Both delta gap and magnetic frill source models are considered. Moreover, the results using a reduced kernel as well as the exact kernel are presented. Both entire basis (EB) and piecewise sinusoidal (PWS) expansion modes are used and the results are compared. The effects of the probe length, feed position, and dielectric constant on the input impedance are discussed. Finally, the theoretical radiation patterns for the first three resonant modes (TE₁₁₁, TM₁₀₁, and TE₂₂₁) of the DR antenna are presented     

Rectangular dielectric resonator antenna for ultrawideband applications

A new dielectric resonator antenna (DRA) is introduced for ultrawideband applications. A rectangular dielectric resonator, a bevel feeding patch and an airgap between the DR and ground plane are used to obtain an ultrawideband impedance bandwidth. The effective dielectric constant and the Q-factor can be reduced by using the airgap and the bevel-shaped feeding mechanism, which can provide a smooth transition from one resonant mode to another. Measured results demonstrate that the proposed DRA has a wide bandwidth from 2.6 to 11 GHz with VSWR less than two, covering the frequency range of more than 120%. Experimental and numerical results are carried out and discussed, showing good agreement.     

Adjustable frequency dielectric resonator antenna

An easy method of tuning the resonant frequency of cylindrical and ring dielectric resonator (DR) antennas using different diameters of conducting plates is presented. This technique can tune a DR antenna to operate at the design frequency without changing antenna performance. The maximum frequency tuning range can reach up to 300-500 MHz     

Small eletric monopole mode dielectric resonator antenna

A novel dielectric resonator (DR) antenna is reported. The lowest order mode of the proposed antenna radiates like an electric monopole. The dimensions of the antenna are much smaller than a previously reported structure radiating in a similar mode, e.g. for an antenna fabricated out of ε_r=20 material, the diameter and height of the DR are ~0.08 λ₀ each     

Experimental investigation for wideband perforated dielectric resonator antenna

A wideband perforated dielectric resonator antenna (PDRA) is presented. The effective permittivity of the dielectric resonator is altered by drilling holes into a circular ring lattice inside the DRA. The PDRA is equivalent of having an annular ring with lower permittivity outside the cylindrical disk, resulting in enhanced impedance bandwidth. The measured bandwidth of a prototype PDRA with relative permittivity 10.2 is 26.7% (S/sub 11/<-10 dB).     

Design of an Ultra‐Wideband Antenna Using a Ring Resonator with a Notch Function

This paper describes an ultra‐wideband (UWB) antenna that uses a ring resonator concept. The proposed antenna can operate in the entire UWB, and the IEEE 802.11a frequency band can be rejected by inserting a notch stub into the ring resonator. The experiment results indicate that the measured impedance bandwidth of the proposed antenna is 17.5 GHz (2.5 GHz to at least 20 GHz). The proposed UWB antenna has omnidirectional radiation patterns with a gain variation of 3 dBi (1 dBi to 4 dBi).     

Embedded dielectric resonator antenna for bandwidth enhancement

A new embedded structure with an annular ring and a cylindrical dielectric resonator excited by means of a coaxial probe has been realised and investigated experimentally to obtain a large bandwidth enhancement. The return loss, radiation patterns, and antenna gain of this configuration are presented. The capability of such an antenna, with a low profile (a/h=6) and 10 dB impedance bandwidths of 32 and 38%, is demonstrated     

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).      

The effect of an offset impedance sheet on the admittance of a slot antenna

The effect of offsetting a plasma (or dielectric) from an infinite slot antenna excited with a TEM mode in a conducting plane is considered, using an impedance sheet as a model for the plasma. Results are obtained for the change in antenna admittance as a function of offset distance for several different values of plasma (dielectric) surface impedance and characteristic antenna dimensions.     

Multiport network description and radiation characteristics ofcoupled dielectric resonator antennas

An efficient procedure is presented to investigate the mutual coupling effects and radiation characteristics of dielectric resonator (DR) antennas operating in an array environment. The procedure is based on the method of moments (MoM) as applied to a system of surface integral equations (SIEs) for the coupling of a dielectric body of revolution (BOR) to a nonBOR geometry. The antenna array elements are situated on a ground plane and fed by coaxial probes. Multiport network impedance parameters computed by this method show good agreement with those obtained by measurement. Computed driving point impedances are given for arrays exhibiting optimum pattern performance in terms of low cross polarization and good pattern symmetry     

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.     

Broadband Dielectric Resonator Antenna With Metal Coating

A broadband dielectric resonator (DR) antenna is proposed, which consists of a rectangular DR coated with metal on three sides and placed on a ground plane. The structure is analyzed by modelling the dielectric-air interface as perfect magnetic conductor (PMC). A coplanar waveguide (CPW) with terminating slots is used to feed the antenna. Measurement results exhibit a wide bandwidth of about 47% over which the E_thetas pattern on the horizontal plane is nearly omnidirectional. The 10-dB bandwidth of this broadband DR monopole covers 4.2-6.8 GHz. Hence, it can be used for WLAN 802.11a applications     

并联介质加载折叠臂偶极天线的辐射特性

介绍了一种由折叠臂偶极天线和并联介质块组成的小型化超宽带天线。分析了天线的辐射机理,应用时域有限差分(FDTD)方法和完全匹配层(PML)技术对天线的辐射特性进行了研究。计算结果表明:驻波系数小于3时,天线的阻抗带宽达到2.4GHz(3~5.4GHz),并且辐射脉冲保形性较好,可用于无载波超宽带无线数据通信系统。