Triple Band Circular Patch Microstrip Antenna with Superstrate

A novel compact triple band slit cut circular patch antenna with superstrate is proposed; slits on the patch provide additional resonances. The superstrate (cover) of dielectric layer provides protection to printed circuit antenna from environmental hazards due to abnormal weather conditions. The slits add two resonances in the resonance of a circular patch to achieve triple band antenna for multi services. The dielectric superstrate or cover above the microstrip patch causes the change in fringing fields between the patch and ground plane. The change in fringing field is accounted to calculate the effective relative permittivity. The effective permittivity is considered to evaluate the changes in resonance frequency due to superstrate. The various parameters of the antenna have been investigated and the antenna is simulated on Ansoft’s HFSS software simulator. A prototype of antenna is fabricated to confirm the return loss by measurement using the Agilent Technologies’ N5230A PNA-L Network Analyzer. The proposed structure with superstrate possess triple band characteristics and provides protection from environmental hazards. The resonating frequencies of the bands are 7.3, 8.7 and 10.3 GHz. The analytical results are found in good agreement with the simulated results obtained by Ansoft’s HFSS and further confirmed by measurement. Antenna is worth for X band operations such as remote sensing, WPAN and military satellite communication and vehicular applications.     

Building a Better Halide Receptor: Optimum Choice of Spacer,Binding Unit,and Halosubstitution

Quantum calculations are used to measure the binding of halides to a number of bipodal dicationic receptors, constructed as a pair of binding units separated by a spacer group. A number of variations are studied. A H atom on each binding unit (imidazolium or triazolium) is replaced by Br or I. Benzene, thiophene, carbazole, and dimethylnaphthalene are considered as spacer groups. Each receptor is paired with halides F^?, Cl^?, Br^?, and I^?. Substitution with I on the binding unit yields a large enhancement of binding, as much as 13 orders of magnitude; a much smaller increase occurs for substitution with Br. Imidazolium is a more effective binding agent than is triazolium. Benzene and dimethylnaphthalene represent the best spacers, followed by thiophene and carbazole. F^? binds much more strongly than do the other halides, which obey the order Cl^?>Br^?>I^?.     

Design and Development of an Efficient EBG Structures Based Band Notched UWB Circular Monopole Antenna

Band notched circular monopole antennas for ultra-wide band applications are proposed in this paper. The proposed antennas in this paper can reject worldwide interoperability for microwave access WiMAX band (3.3–3.8 GHz) and wireless local area network WLAN band (5–6 GHz). Antennas utilises mushroom-type electromagnetic band gap (EBG) structures and I-slot embedded edge located via (ELV) EBG structures to achieve band-notched designs. The advantages of band notched designs using EBG structures like notch-frequency tuning, dual-notch antenna designs and stable radiation pattern are also verified. Various antenna designs with slot in EBG structures, variations in placement of EBG structures, number of EBG structures and ELV type EBG structures are simulated. About 30% reduction in size of EBG structures is obtained if conventional mushroom type EBG is replaced by proposed I-slot embedded ELV-EBG structure. Fabricated and measured results are in good agreement with simulated ones.

     

A Dual Polarized Triple Band Stacked Elliptical Microstrip Patch Antenna for WLAN Applications

In this paper, a single coaxial feed dual polarized triple band stacked microstrip patch antenna for wireless applications is presented. The proposed stacked antenna has two resonating elements with lower layer consisting of a truncated corner square patch and upper layer with an elliptical patch. Both the layers of proposed antenna are printed on RT Duroid^® 5880 substrate (having ?_r?=?2.2). The antenna shows triple band resonance at 4.2, 4.8 and 5.8 GHz with circular polarization behaviour at the first two resonances and linear polarization characteristic in the third resonance respectively. The typical realized gain of proposed antenna is around 7 dB in all three resonating bands.     

Sequence spaces of fuzzy real numbers defined by Orlicz functions

In this article we study different properties of convergent, null and bounded sequence spaces of fuzzy real numbers defined by an Orlicz function, like completeness, solidness, symmetricity, convergence free etc. We prove some inclusion results, too. The work of the first author was carried under University Grants Commission of India project No.-F. No. 30-240/2004 (RS).     

New constructions of two slim dense near hexagons

We provide a geometrical construction of the unique slim dense near hexagon with parameters (s,t,t₂)=(2,5,{1,2}). Using this construction, we construct the rank 3 symplectic dual polar space DSp(6,2) which is the unique slim dense near hexagon with parameters (s,t,t₂)=(2,6,2). Both near hexagons are constructed from two copies of the unique generalized quadrangle with parameters (2,2).