In this article, a high‐permittivity rectangular dielectric resonator antenna is proposed. In this configuration, wideband operation is achieved by loading a rectangular dielectric resonator on the center of the rectangular ring slot. Dielectric resonators of three different thicknesses have been studied. In this configuration, slot acts as an effective radiator and the feeding structure of the dielectric resonator. The dual‐band resonances of the two radiators, i.e., slot and dielectric resonator are combined to extend the antenna bandwidth. The measured impedance bandwidth obtained is about 81.7%. The return loss, radiation pattern, and half power beam widths are measured and presented. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1077–1079, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25927

AgPb2B2V3O12 (B = Mg, Zn) ceramics with low sintering temperature were synthesized via the conventional solid‐state reaction route. Rietveld refinements of the X‐ray diffraction patterns confirm cubic symmetry with space group Ia3¯d. The number of observed vibrational modes and those predicted by group theoretical calculations also confirm the Ia3¯d space group. At the optimum sintering temperature of 750°C/4 hours, AgPb2Mg2V3O12 has a relative permittivity of 23.3 ± 0.2, unloaded quality factor (Qnormalu×f) of 26 900 ± 500 GHz (f=7.57GHz), and temperature coefficient of resonant frequency of 19.3 ± 1 ppm/°C, while AgPb2Zn2V3O12 has the corresponding values of 26.4 ± 0.2, 28 400 ± 500 GHz (f=7.21GHz) and –18.4 ± 1 ppm/°C at 590°C/4 hours. Microwave dielectric properties of a few reported garnets and Pb2AgB2V3O12 (B = Mg, Zn) ceramics were correlated with their intrinsic characteristics such as the Raman shifts as well as width of A1g Raman bands. Higher quality factor was obtained for lower full width at half‐maxima (FWHMs) values of A1g modes. The increase in B‐site bond valence contributes to high Qnormalu×f and low |τf| with the substitution of Zn2+ by Mg2+. Furthermore, the high ionic polarizability and unit cell volume with Zn2+substitution contribute to increased relative permittivity.

Cold sintering process (CSP) was successfully employed to fabricate (1 − x) NaCa2Mg2V3O12-xNaCl [abbreviated as (1 − x) NCMVO-xNaCl] microwave dielectric ceramics. (1 − x)NCMVO-xNaCl ceramics prepared at 200°C and at a pressure of 450 MPa had a high relative density of 80–94%. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy showed that both NCMVO and NaCl phases co-exist in all composite ceramics without forming any secondary phase. Further, dependence of microstructure and dielectric properties on cold sintering temperature and duration were investigated in detail and their optimized values to obtain maximum density of ceramic composites were 200°C and 50 min, respectively. (1 − x)NCMVO-xNaCl (x = 0.4–0.7) composites have relative permittivity (εr) in the range of 6.9–7.4, and a reasonably high microwave quality factor (Q × f) of 5,000 to 13,830 GHz.

Novel slot‐fed dielectric resonator antenna is studied experimentally. The antenna is comprised of a rectangular dielectric resonator and a mictrostrip fed coupling slot. The multiband resonances of the two radiators i.e., slot and dielectric resonator are combined to extend the antenna bandwidth. Dielectric resonator of three different thicknesses is studied, providing a bandwidth of 49.25%. The radiation patterns are measured and are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 316–318, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24937

A stacked rectangular dielectric resonator antenna (DRA) is studied experimentally. The achieved impedance bandwidth of two DR stacked antenna is about 73%. By stacking two different permittivity DRs, the multi‐band of single element DRA is changed to single wideband giving out improvement in bandwidth. The antenna parameters like radiation patterns and return loss are measured and presented. These antennas may provide applications in which large bandwidth is needed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2432–2434, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25503