-The crystalline and osmotic swelling of N~, Cs-, Mgand Ca-montmorillonite has been measured in dimethyl sulphoxide and in formamide, N-methyl formamide, dimethyl formamide, N-methyl acetamide and dimethyl acetamide. These liquids have similar dipole moments but their relative permittivities vary appreciably from values less than water to values greater than water. Na montmorillonite exhibits o...

Electrically small oblate spheroidal and spherical antennas in confocal shells with negative permittivity represent perspective antenna design to combine moderately small size, wide bandwidth, high efficiency and power of radiation. However, optimization of the antennas performance parameters imposes contradictory restrictions on permittivity of the shells, electrical size of the antennas, shap...

In this article, a novel frequency slot-based switchable antenna fabricated on flexible and nonflexible materials is presented for suitable reconfigurable radiations of Bluetooth, WiMAX, upper WLAN applications. Initially, the performance structure was simulated using CSTTM simulator evaluated experimentally FR4 structure. The same implemented (jean) substrate with relative permittivity 1.7. pr...

This work presents an analytic model to derive the scan impedance of planar infinite phased arrays dipoles at a dielectric interface when only (0, 0) Floquet mode propagates. The proposed builds on boundary conditions met by fundamental provide novel derivation equivalent circuit for impedance. analysis is also extended include effect sufficiently thick grounded substrate that does not affect e...

A new, efficient, and accurate analytical model is introduced for estimating the beam direction of rampart line antennas with microstrip radiators that can change feeding frequency. The takes its origins from 1-D array theory, in which bends represent radiating elements, interconnecting lines phase shifters. mathematical expression accounting equivalent length correct estimation distance betwee...

Recent advances in hyperbolic metamaterials have spurred many breakthroughs the field of manipulating light propagation. However, unusual electromagnetic properties also put extremely high demands on its compositional materials. Limited by finite relative permittivity natural materials, effective constructed is confined to a narrow range. Here, based proposed concept structure-induced spoof sur...

An unfilled tungsten bronze-structured ferroelectric ceramic, Ca0.28Ba0.72Nb2O6 (CBN28), has been doped with Y3+ to produce ceramics a nominal composition, (Ca0.28Ba0.72)1–3w/2YwNb2O6 [0 ≤ w 0.05]. The substitution of for Ca2+/Ba2+, and consequent additional vacancy formation, is assumed occur on the A1/A2 sites. This resulted in minor reduction c lattice parameter, unit cell volume. For undope...