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Abstract-A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper. The structure is realized by inserting splitring slots inside two reversely connected rectangular patches, which is known as a split-ring slotted electromagnetic bandgap (SRS-EBG) structure. The bandgap properties of the EBG structure are examined by the suspended microstrip line and finite element methods (FEM). The achieved bandgaps have widths of 4.3 (59.31%) and 5.16 GHz (38.88%), which are centered at 7 and 13 GHz, respectively. The SRS-EBG is applied to enhance the performance of a single-element microstrip patch antenna (at 7 GHz) and a two-element array (at 13 GHz) configuration. A wider bandwidth is obtained with a better reflection coefficient level for the single element antenna; a reduction in mutual coupling of more than 20.57 dB is obtained for the array design. In both cases, the gain and radiation characteristics are improved. The results are verified by measuring the fabricated lab prototype, and a comparison with the computed results showed good agreement.

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In this paper, heat transfer characteristics of a two-dimensional steady hydromagnetic natural convection flow of a micropolar fluid passed a non-linear stretching sheet taking into account the effects of a temperature-dependent viscosity and variable wall temperature are studied numerically for local similarity solutions by applying the Nachtsheim-Swigert iteration method. The results corresponding to the dimensionless temperature profiles and the local rate of heat transfer are displayed graphically for important material parameters. The results show that in modeling the thermal boundary layer flow with a temperature-dependent viscosity, consideration of the Prandtl number as a constant within the boundary layer produces unrealistic results and therefore it must be treated as a variable rather than a constant within the boundary layer. The results also show that the local rate of heat transfer strongly depends on the non-linear stretching index and temperature index.

In this paper the Dufour and Soret effects on mixed convection flow past a vertical porous flat plate embedded in a porous medium have been studied numerically. The governing non-linear partial differential equations have been transformed by a similarity transformation into a system of ordinary differential equations, which are solved numerically by applying NachtsheimSwigert shooting iteration technique together with sixth order Runge-Kutta integration scheme. For fluids of medium molecular weight (H2, air), profiles of the dimensionless velocity, temperature and concentration distributions are shown graphically for various values of suction parameter fw, Dufour number Du and Soret number Sr. Finally, numerical values of physical quantities, such as the local skin-friction coefficient, the local Nusselt number and the local Sherwood number are presented in tabular form.

The Dufour and Soret effects on unsteady MHD free convection and mass transfer flow past an infinite vertical porous plate embedded in a porous medium have been studied numerically. The non-linear partial differential equations, governing the problem under consideration, have been transformed by a similarity transformation into a system of ordinary differential equations, which is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with sixth order Runge-Kutta integration scheme. The effects of various parameters entering into the problem have been examined on the flow field for a hydrogen-air mixture as a non-chemical reacting fluid pair. Finally, the numerical values of local Nusselt number and local Sherwood number are also presented in tabular form.