A compact very-high-permittivity dielectric-eye resonator antenna for multiband wireless applications

very-high-permittivity (e, = 100) multiband dielectrice> e resonator antenna is presented. The compact antenna, excited by a m:'crostrip line, resonates at two frequencies centered around the 1.9- GHz and 2.4-GHz bands with identical polarization . The behavior of the antenna at different positions along the feed line is studied and optimized. Multiple resonances with the same polarization and broad radioticn patterns suggest the suitability of the antenna for multiband wireless application

Low backscattered dual-polarised metallo-dielectric structure based on sierpinski carpet

A novel technique for backscattering reduction for both TE and TM polarisation, employing a metallo-dielectric structure based on Sierpinski carpet fractal geometry, is reported. A reduction in backscattered power of --30 dB is obtained for normal incidence in the X-band for the structure using the third iterated stage of the fractal geometry

Characteristics of a Microstrip-Excited High-Permittivity Tectangular Dielectric Resonator Antenna

The radiation characteristics of a microstrip-line-excited rectangular dielectric resonator antenna (DRA) are studied experimentally.The radiation charactristics and excitation of different modes are highly influenced by the orientation of the DR,feed line parameters ,and finite size of the ground plane

A new method for load matching in multimode microwave feating applicators based on the use of dielectric layer superposition

Usage of a dielectric multilayer around a dielectric Sample is studied as a means for improving the efficiency in multimode microwave- heating cavities. The results show that by using additional dielectric constant layers the appearance of undesired reflections at the sample-air interface is avoided and higher power -absorption rates within the sample and high -efficiency designs are obtained

Wideband Oylindrioal Dielectric Resonator Antenna Excited Using an L-strip Feed

A broadband cylindrical dielectric resonator antenna (DRA) energized with an L-strip feed is presented The novel exciting technique achieves a 2:1 VSWR bandwidth of 18%. The variation of bandwidth for different feed parameters is also studied

T-strip-fed High-Permittivity Rectangular Dielectric Resonator Antenna for Broadband Applications

rectangular low-density, high-permittivity dielectric resona or antenna (DRA) excited by T-shaped microstrip feed offering a 2:1 VSWR bandwidth of -22% at 2.975 GHz is reported. The design methoaology and experimental results of the antenna are discussed. The excellent gain and radiation performance of the proposed antenna project: it as a potential candidate for telecommunication applications

L-strip-fed Wideband Rectangular Dielectric Resonator Antenna

In this paper, the advantages of using L-shaped microviij) feed to e.tcite a rectangular dielectric resonator cuuenna (DRA) by elemanagnetic coupling are presented. This feeding technique enhances the hardsvidth and gain of the antenna without affecting its size. The experimental re srdts are validated using Fidelity software based on the finitedifference tine-domain (FDTD) method

Rectangular Dielectric Resonator Antenna on a Conductor-backed Co-planar

In this paper, we present an effective excitation of a reelangular dielectric resonator antennas (DRA) with a conductor-hacked coplanar waveguide (CB-CPW). The radiation and resonance characteristics are found to van,, depending on the orientation of the DR on doe coplanar feed line. The effect of finite and infinite ground planes of CB-CPIV on the radiation characteristics of the rectangular DRA is studied. The orientation and position of the DR are optimized for maximum gain and bandwidth. The optimized antenna ,geometry offers --10.46 dBi gain and 7.5% bandwidth with low cross-polar radiation characteristics

Preparation and Microwave Characterisation of Ba2-xSrx Ti9 O20 Cermics

Ceramics of composition BaO-Ln2O3-STiO2 have been prepared with four elements (Ln=La,Pr,Nd.Sm) by a conventional solid state ceramic preparation route and the dielectric properties measured in the microwave frequency range

Preparation, Characterization and Dilectric Properties of Ceramics in the BaO-Nd2O3-TiO2 System

The dielectric ceramics BaNd2Ti3Oto, BaNd2Ti4O12 and BaNd2Ti5O14 have been prepared by Conventional solid state ceramic route. The sintered ceramic samples have been characterized by X-ray diffraction and Scanning Electron Microscopy (SEM). The dielectric properties in the microwave frequency range have been measured using conventional microwave dielectric resonator methods. The BaNd2Ti1O10, BaN2Ti4O12 and BaNd2Ti5O14 have dielectric constants (Er) ~ 60, 84 and 77 respectively. They have relatively high quality factors

Microwave dielectric properties of (1-x)CaTi03-xSm(Mg1 /2Ti1/2)03 [0. 1 _ceramics

The microwave dielectric properties of (I -x)CaTiO3-xSm(Mg1/2Tit,2)O3(0.1 <-x< 1.0) have been investigated. The system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 86 to 25 as x varies from 0.1 to 1.0. The Qxf varies non-linearly and increases for composition with x> 0.6. The nonmonotonic variation with composition x is more pronounced in Tt than in er. The microwave dielectric properties indicate the possibility of a phase transformation for x between 0.4 and 0.5

Tailoring the Microwave Dielectric Properties of GdTiNb 1 _-xTa,O6 and Sm 1 _X Y,TiTa06 Ceramics

Microwave dielectric ceramics based on GdTiNb,-,.Ta,O6 and Sml _.,Y,TiTa06 have been prepared by conventional solid state method . The GdTiTaO6 and SmTiTaO6 have aeschenite structure with positive rr and GdTiNbO6 and YTiTaO6 have euxenite structure with negative rr. The rr of the ceramics has been tuned by preparing solid solution phases between the aeschynites and euxenites for a possible zero rr material . It is observed that GdTiNbt_YTa.,O6 undergoes a phase transition from aeschynite to euxenite when x=0.75 and in Sml-,YxTiTa06 for x= 0.73. The microwave dielectric properties change abruptly near the transition region . The rr value approaches zero near the phase transition region while the samples have poor sinterability and poor quality factor . The unloaded quality factor, dielectric constant and the sign of rr of the solid solution phases are found to depend on the average ionic radius of the rare earth ion in RE ,-5RE',TiTaO6. The boundary of the euxenite-aeschynite phase transition occurs at an average ( RE) ionic radius of 0.915 A in Sm,_, Y,.TiTaO6 solid solution phases

Microwave Dielectric Properties of Ba(Mg1/3Ta(2-2x)/3Wx/3Tix/3) 03 Ceramics

microwave dielectric properties of ceramics based on Ba(Mgv3Ta(2-2x)t3W,t3Tixt3)O3 is investigated as a function of x. The 15 densification as well as dielectric properties deteriorate with increase in the substitution levels of (Ti 1,3W113)333 + at (Ta213)3.33+ site 16 in Ba(Mg113Ta213)03. The rt is approaching zero between x = 0.1 and 0.15 in Ba(Mg it3Ta(2-2,,.)t3W,it3Ti,Tt3)O3 where quality factor is 17 reasonably good (Qu x f = 80,000-90,000 GHz). The Ba(Mg1,3Ta(2_,013W,13Ti,,13)03 with x = 1.0 has e, = 15.4, rf= -25.1 ppm/ 18 "C, Q„ x f = 35,400 GHz

The effect of dopants on the microwave dielectric properties of Ba( Mgo.33Ta0.67)03 ceramics

The effect of dopants with different valencies and ionic radii on the densification, structural ordering, and microwave dielectric properties of Ba(Mg1t3Tazt3)O3 (BMT) is investigated. It is found that dopants such as Sb,05, MnO, ZrO,, WO1, and ZnO improve the microwave dielectric properties of BMT. Addition of trivalent dopants is detrimental to the cation ordering and dielectric properties of BMT. A correlation between the microwave dielectric properties of BMT and ionic radii of the dopant has been established. The variation of the dielectric properties of pure and doped BMT at cryogenic temperatures is also discussed