Toward Wideband Frequency Rejection: An Efficient Frequency Selective Scheme

This paper outlines a Frequency Selective Surface configuration designed for wideband filtering characteristics. The proposed design topology includes two-layer conductive elements printed on an FR4 substrate with a thickness of 1.6 mm. On the front side, a square loop and four branches are placed, and on the other side of the substrate, there is another square loop supported by two modified vertical arms. The use of square loops as one of the trendy elements in frequency selective designs provides the opportunity to tune the resonances and obtain the desired Performance; The proposed 10 mm × 10 mm frequency selective surface unit cell structure rejects the frequency band of 2-14 GHz covering WiMAX, WLAN, and X band in-service frequency ranges. It has three resonant frequencies and works well in various incident angles. There is a good match between the simulated results and the tested results. Stable frequency response, simple structure, and easy production are useful features of the developed scheme.

La induced Si3 trimer bilayer on Si(111) surface

Using first-principles calculations, we identify a robust (√3 × √3)R30° reconstruction of Si3 trimer bilayer on Si(111) surface with a La coverage of 2/3 monolayer. In each surface unit cell,...

Electromagnetic Optimization Of Ultra-Thin Resonant Absorbers For Bolometric Detectors Of The Submillimeter-Wave Range

We present the results of theoretical analysis and characteristics optimization for ultra-thin resonant absorbers based on artificial impedance surfaces, which are promising for using as the radiation-sensitive layers in selective bolometric detectors operating in the range of submillimeter waves. The key parameters of the ultra-thin absorbers, such as the absorption resonance Q-factor, the ratio of the peak absorptivity wavelength to the absorber thickness and the impedance surface unit cell size, are traced versus a geometric shape of the resonant elements and their electrical conductivity.

A New Geometric Model for Three-Dimensional Braided Composites

According to the structural features of 3-D braided composites, the whole structure is divided into three types of sub-unit cells, these are the interior unit cell, the surface unit cell and the corner unit cell. Considering the bending of fiber bundle and the deformation of cross-section which are caused by the space fiber extrusion and twist together, the corresponding geometric analysis models for every type of sub-unit cell are established, and the engineering elastic constants of the 3-D braided composites are predicted. The results show that the calculated results well agree with the experimental results, and the effectiveness of the model is verified.

THE CO-ADSORPTION OF BENZENE ANDCOONCo(0001)

The co-adsorption of carbon monoxide and benzene on Co (0001) has been studied using density functional calculations. We used the ordered [Formula: see text] surface unit cell. A comparison of the co-adsorption with CO and benzene two-dimensional networks is also given. The electronic structure reveals that the CO orbitals interact with benzene and Co layer. Regarding the bonding, the Co–Co overlap population decrease 18% after benzene adsorption and increase a little after CO adsorption with a net 14.6% decrease in the co-adsorption system. The CO –benzene interaction is shown by the changes in the C – O ( CO ) and C – H (benzene) bonds.