This paper presents a novel implementation of an electromagnetically coupled patch antenna using air gap filled substrates to achieve the maximum bandwidth. We also propose an efficient modeling technique using the FDTD method which can substantially reduce the simulation cost for modeling the structure. The simulated results have been compared with measurement to show the broadband behavior of the antenna and the accuracy of the proposed modeling technique. The measured results show a 16% of VSWR<2 bandwidth which is considerable considering the inherent bandwidth limitations in microstrip antenna technology.

This experiment was conducted to study the effects of aqueous and alcoholic extracts of Camellia sinensis leaves (green tea), Punica granatum peel (pomegranate-peel), and Quercus persica (oak) at different concentrations on ruminal fermentation, dry matter and organic matter digestibility, methane production and protozoa population using gas production method. Experimental treatments were: control, 50, 100, and 200 μg/ ml aqueous and methanolic extract of Camellia sinensis, Punica granatum peel, and Quercus persica (19 treatments in total). Cumulative gas production was recorded at 2, 4, 6, 8, 12, 24, 36, 48, 72, and 96 h after incubation. Dry matter digestibility (DMD), organic matter digestibility (OMD), metabolizable energy (ME), pH, and short-chain fatty acids (SCFA) were calculated after 24 h incubation. Gas production at different times, methane production, and protozoa population were also measured. DMD, OMD, and pH were decreased by adding extracts. Microbial mass production (MCP) and microbial mass production efficiency (EMCP) significantly increased at a low level (50 μg/ ml) and significantly decreased at high levels of extracts containing tannins (100 and 200 μg/ ml) (P< 0.01). The treatments also increased short-chain fatty acids (SCFA), reduced methane concentration, and reduced PF and protozoa populations only at the highest levels of extracts (P<0.05).