共查询到20条相似文献,搜索用时 15 毫秒
1.
Junker G.P. Kishk A.A. Glisson A.W. 《Antennas and Propagation, IEEE Transactions on》1998,46(3):425-433
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 相似文献
2.
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. 相似文献
3.
Dual-polarized dielectric resonator antennas 总被引:1,自引:0,他引:1
Yong-Xin Guo Kwai-Man Luk 《Antennas and Propagation, IEEE Transactions on》2003,51(5):1120-1124
Two high input-isolation dual-polarized dielectric resonator (DR) antennas are presented in this communication. First, a slot-coupled feed technique with two narrow slots forming a "T" configuration is employed to design a dual-polarized DR antenna. Input isolation exceeding 35 dB has been obtained in the band for this design. Secondly, a hybrid feed mechanism with a coplanar waveguide (CPW) feed and a slot feed is used to achieve a dual-polarized DR antenna. A vertical strip is added at the center strip of the CPW feed to improve the coupling to the DR antenna. Also, input isolation exceeding 35 dB has been obtained in the band. Good cross-polarization levels less than -20 dB in the broadside direction are attained. The measured far-field radiation patterns are stable in the passband and the measured gains are around 5.5 dBi for the two feed ports of both cases. 相似文献
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The input impedance of stacked cylindrical dielectric resonator antennas is investigated experimentally. The dielectric resonators are made of different materials. The bandwidth of 25% has been observed for a standing wave ratio better than 2.<> 相似文献
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Bandwidths of the coaxial fed and aperture coupled cylindrical dielectric resonator antennas (DRAs) with broadside radiation patterns are enhanced by exciting the HEM/sub 11/spl Delta// (1相似文献
8.
Junker G. P. Kishk A. A. Glisson A. W. 《Antennas and Propagation, IEEE Transactions on》1996,44(5):600
Dielectric resonator antennas (DRAs) excited by a narrow-slot aperture in a conducting ground plane are analyzed using a numerical technique based upon a surface-integral equation formulation for bodies of revolution (BORs) coupled to non-BOR geometries. An efficient matrix-solution algorithm, together with a simple microstrip transmission-line model or a delta-source model are used to compute the antenna input impedance. Input impedances obtained with this technique show favorable agreement to those obtained via another numerical technique, as well as to those obtained by measurement 相似文献
9.
Kwai-Man Luk Wai-Kee Leung Kwok-Wa Leung 《Antennas and Propagation, IEEE Transactions on》1994,42(12):1652-1654
The mutual coupling between two hemispherical dielectric resonator antennas is studied analytically. The radiation fields of the antennas are derived rigorously from a Green's function. The mutual impedance is then determined from a reaction formula. Comparison between theory and experiment is presented 相似文献
10.
Kranenburg R.A. Long S.A. Williams J.T. 《Antennas and Propagation, IEEE Transactions on》1991,39(1):119-122
The circuit and radiation properties of a cylindrical dielectric resonator antenna excited by a coplanar waveguide feed are investigated. The coupling between the feed and the radiator was measured as a function of the position, dielectric constant, and height of the cylinder. The radiation patterns and resonant frequencies were also measured. These measured results are found to be in good agreement with theoretical calculations 相似文献
11.
A compact array of circular polarised cross-shaped dielectric resonator antennas (XDRAs) is presented. The array consists of 2×2 XDRAs elicited by microstrip-fed slot apertures in the X-band. By using sequential rotation to feed the XDRAs, the circular polarisation bandwidth is significantly increased from 5% for the individual XDRA to 16% in the array. The array also achieves a wide impedance bandwidth: a 10 dB return loss was maintained over a 25% bandwidth 相似文献
12.
Petosa A. Simons N. Siushansian R. Ittipiboon A. Cuhaci M. 《Antennas and Propagation, IEEE Transactions on》2000,48(5):738-742
The multisegment dielectric resonator antenna (SDRA) has previously been developed to significantly enhance the coupling to a microstrip line. The MSDRA greatly facilitates the integration with a printed feed distribution network for use in a large array environment. The thickness and permittivity of the dielectric insert of the MSDRA can be adjusted to match the element impedance to that of the feed line. A detailed study of the effects of varying the dielectric insert parameters was carried out and useful guidelines are presented for the design of MSDRAs 相似文献
13.
Wideband dielectric resonator antennas are designed by shaping the dielectric materials. New dielectric resonator antennas of conical shape are experimentally examined and some results are verified numerically. Four different cone shapes are considered. The excitation is considered to be a coaxial probe displaced from the cone axis. Two configurations show wideband performance. The split cone achieved about 50% impedance bandwidth. The radiation patterns are computed within the band to examine the effect of the different modes excited on the radiation patterns 相似文献
14.
A wideband aperture coupled flipped staired pyramid shaped DRA is presented. An impedance bandwidth of 62% (S/sub 11/<-10 dB) is measured. The proposed DRA has a stable broadside radiation pattern across the matching band, with an average gain of 6.5 dBi. Simulation results obtained from Fidelity give good agreement with measured results. 相似文献
15.
Shiu-Ming Shum Kwai-Man Luk 《Antennas and Propagation, IEEE Transactions on》1998,46(3):325-333
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 HEM11δ 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 相似文献
16.
The gain characteristics of a dielectric resonator loaded coaxial fed circular waveguide antenna (DRLWA) with overlaying parasitic discs have been investigated experimentally. Results indicate that, when properly spaced, the overlays can enhance the gain by more than 6 dB.<> 相似文献
17.
Venkatarayalu N.V. Chi-Chih Chen Teixeira F.L. Lee R. 《Antennas and Propagation, IEEE Transactions on》2004,52(5):1318-1323
A detailed characterization of the input impedance of ultrawide-band (UWB) dielectric horn antennas is presented using the finite-difference time-domain (FDTD) technique. The FDTD model is first validated by computing the characteristic impedance of two conical plate transmission lines (including planar bow-tie antennas) and comparing the results to analytical solutions. The FDTD model is next used to calculate the surge impedance of dielectric horn antennas using the conical plates as launchers. Design curves of the surge impedance for different choices of geometries and dielectric loadings are provided. The modeled antennas are particularly attractive for applications such as UWB ground penetrating radars (GPR) applications. 相似文献
18.
Kishk A.A. Chair R. Kai Fong Lee 《Antennas and Propagation, IEEE Transactions on》2006,54(8):2182-2189
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. 相似文献
19.
Sounas D.L. Kantartzis N.V. Tsiboukis T.D. 《Microwave and Wireless Components Letters, IEEE》2006,16(2):63-65
A dispersion-optimized alternating-direction implicit finite-difference time-domain (ADI-FDTD) method is presented in this letter for the accurate modeling of complex electromagnetic structures. The analysis focuses on circularly polarized slot-coupled microstrip and dielectric resonator antennas. Introducing a class of three-dimensional spatial/temporal operators, the novel algorithm yields robust curvilinear grids which efficiently treat fine details and interfaces. Hence, the serious dispersion errors of the usual schemes, as time-steps surpass the Courant limit, are greatly reduced, enabling fast broad-band simulations. Numerical validation confirms the above merits via various realistic structures. 相似文献
20.
Fasenfest B.J. Walsh A.G. De Young C.S. Kennedy T.F. Long S.A. Williams J.T. 《Electronics letters》2003,39(1):12-13
An experimental investigation studied a cylindrical dielectric resonator antenna placed in a conducting well. Both the resonant frequency and input impedance increased as the wells became smaller, but the radiation patterns remained essentially unchanged. Resonators with smaller height-to-diameter ratios showed these effects to a lesser degree. 相似文献