A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented. These antennas which are taken into account are listed as wide-band microstrip antenna, wide-band monopole antenna over a plate, wide-slot UWB antenna, stacked patch UWB antenna, taper slot (TSA) UWB antenna, metamaterial (MTM) structure UWB antennas, elliptical printed monopole UWB antenna, and flexible wearable UWB antenna. The antennas’ performance is compared based on their size and how they can be applicable for portable communication device applications. This review paper furnishes a proper direction to select varieties of figures in terms of impedance bandwidth, gain, directivity, dimensions, time domain characteristics, and materials affecting these antenna’s characteristics.

In this study, a polypyrrole-chitosan layer was applied to detect zinc and nickel ions in aqueous solution using surface plasmon resonance. The resonance angle shift was found to monitor the binding interaction between ions and the polymer film. The polypyrrole-chitosan film was coated on the gold layer with an electrochemical deposition method. The Langmuir model was compared with the Freundlich model to explain the binding. Consequently, the Langmuir model was fitted with experimental data better than the Freundlich equation, and the detection limit was 0.01 ppm.

Water conservation and prevention of salt accumulation are important issues in arid and semi-arid regions. Mulching is the most frequently used method for water conservation and prevention of salt accumulation. A mulch with various layers, hence named layered mulch (LM), was applied for reclamation of saline soil. The LM comprises of a light-colored mineral, farmyard manure, and common reed (Arundo donax L.). Two treatments, one with LM and the other without LM (NLM), were carried out on saline soil for 2 years. Soil temperature, water content, and electrical conductivity (EC) were measured during March and September at the depths of 1 to 120 in 4 cm intervals. The results showed that LM soil had a lower temperature and EC than NLM soils. The LM soil recorded higher soil water content than the NLM soil. The LM soil had a lower temperature possibly because it reflected the sunlight, had high heat capacity, and was less permeable to heat conduction. Consequently, the lower temperature in LM soil resulted in higher soil water content and this can be a soil condition, that enables enhanced salt leaching by subsequent rains.

This paper presents the development and design of proximity coupled feed patch antenna as a bio-sensor. This sensor system consists of a two-layer Flame Retardant (FR-4) patch antenna coated with Multi Walled Carbon Nanotubes (MWCNTs) for absorbing bio-molecules. The best design of patch antenna is chosen based on simulation results using Computer Simulation Technology (CST) microwave studio software. After adding bio-material on the top of antenna and interaction with MWCNTs based on the changes in the effective dielectric constant, the resonant frequency of patch antenna is changed. Experimental results have shown 1 MHz change in resonant frequency of patch antenna upon exposure to ethanol. Based on operating frequency (5 GHz) this technique can be used in network sensor systems to measure bio-materials in future research.

The surface plasmon resonance sensor was used to detect and measure low concentrations of sugar. A polypyrrole–chitosan–BaFe₂O₄ nanocomposite layer was prepared to improve the surface of the gold layer for the detection of glucose, fructose, and sucrose using the surface plasmon resonance technique. The polypyrrole–chitosan–BaFe₂O₄ was synthesized using the electrodeposition method in different thicknesses. The functional group, crystal structure, and morphology of the layer were investigated with Fourier transform infrared spectroscopy, X-ray diffraction technique, and field emission electron microscopy. Consequently, the BaFe₂O₄ was scattered on the surface of the polymer, and the affinity of polypyrrole–chitosan–BaFe₂O₄ to bond with glucose is higher than that for the other sugars. The sensor limit was 0.005 ppm.