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With the emergence of smart devices, the antennas that can fulfil the requirements of such devices are very much in demand. As the devices should be connected to the internet, antennas that are aesthetically good and easy to interface anywhere on the routers or repeaters are needed. One of the solutions to this problem is by using transparent antennas that are visibly neutral and can be placed anywhere in the system. Transparent antennas integrated with dielectric resonator (DR) elements lead to fewer conduction losses due to the high dielectric constant of DR, and so an antenna resonating in the frequency band of 2.4 GHz (IEEE 802.11) WLAN applications is proposed that was simulated using Ansys High-Frequency Structure Simulator (HFSS) software. The optical transparency along with wide impedance bandwidth (31.26%), directional radiation pattern, gain and efficiency values greater than 1.5 dBi, and 75%, respectively makes the antenna suitable for smart wireless applications. The DRA fabricated using transparent material AgHT-8, Plexiglas, and Borosilicate glass show good agreement with the simulated results.

The Refractive index and viscosity are important physico-chemical properties of solutions that have many applications in research and industrial works. In this study, we measured the refractive index and viscosity for binary solutions of (water + sodium acetate), (water + sodium carbonate), and (water + trisodium citrate), as well as ternary solutions of (water + sodium acetate + glycerol), (water + sodium carbonate + glycerol), and (water + trisodium citrate + glycerol) in a wide range of mole fractions of solutes at T = (293.15, 298.15 and 303.15) K and atmospheric pressure. These measurements were done in order to study on the interactions between solute and solvent species in our studied solutions at different temperatures. For binary mixtures, the measured refractive indices were correlated with a linear equation. The values of constants of this linear equation, Kr,s, can help us to better understand the power of interaction between solute and solvent species in binary solutions of this study. Also, for ternary solutions of this study, the values of refractive index were calculated using a multiple equation that was suggested by Koohyar in 2018. Jones-Dole equation and Kumar equation were used for fitting viscosities of all solutions at different temperatures. In addition, the values of change of refractive index on mixing, ΔnD, and activation energy for viscous flow, Ea(vis), were calculated using refractive index and viscosity data, respectively. For binary solutions of this study the values of ΔnD were fitted by Redlich-Kister polynomial equation. For ternary solutions of this study the values of ΔnD were fitted by Singe et al., Calvo et al., and also, Nagata and Sakura equations.

A very wideband circularly polarized (CP) crossed dipole antenna is presented in this paper. The primary radiating element of the antenna consists of two straight dipoles arranged orthogonally through double printed rings. To further enhance the axial ratio bandwidth, a cavity with proper size and single parasitic element are employed to generate two additional bands. The use of cavity reflector is investigated thoroughly, providing a solid framework for designing this type of antennas. The final design with an overall size of 0.92λo × 0.92λo × 0.32λo at the center CP frequency yields a measured –10 dB-impedance bandwidth of 75.2% and 3 dB-axial ratio bandwidth of 67.7%. The proposed antenna exhibits right-handed circular polarization and an average broadside gain of about 8.3 dBi over the CP operating bandwidth.