Nanoscale bowtie aperture antennas can be used to focus light well below the diffraction limit with extremely high transmission efficiencies. This paper studies the spectral dependence of the transmission through nanoscale bowtie apertures defined in a silver film. A realistic bowtie aperture is numerically modeled using the Finite Difference Time Domain (FDTD) method. Results show that the tra...

This paper presents a comparative study of Frequency Hopping Spread Spectrum and Direct Sequence Spread Spectrum techniques. The Transmitter and Receiver have been implemented using MATLAB. Maximum-length sequences, Gold Sequences and Walsh Codes have been used as the pseudorandom codes for transmission. Finally received signal have been evaluated on the basis of Bit Error Rate for all the used...

Cognitive radio (Mitola III, 2000) also known as opportunistic spectrum access (OSA) has emerged as a promising solution to increase the spectrum efficiency Haykin (2005). In OSA, the SU finds spectrum holes (white space) by sensing the radio frequency spectrum. The presence of spectrum holes in the PU channels are highlighted in Fig. 1. These spectrum holes are used by the SU for its transmiss...

nano-sized titanium dioxide tio2 powder was prepared by new wet chemical route from its precursor titanium (iv) chloride (ticl4) as precursor with isopropoxy alcohol in presence of nitric acid under ambient condition. their morphologies, phase compositions and components of the tio2 nanoparticles were characterized by transmission electron microscopy (tem), field emission scanning electron micr...

there are many different ways to subdivide the spectrum of a bounded linear operator; some of them aremotivated by applications to physics (in particular, quantum mechanics). in this study, the relationship betweenthe subdivisions of spectrum which are not required to be disjoint and goldberg's classification are given.moreover, these subdivisions for some summability methods are studied.

Cognitive radios network is programmable wireless devices to monitor spectrum used, and networking protocol as needed for better network and application performance. In Cognitive radio networks detection of licensed user reappearance during the nonlicensed user transmission is very much required. This paper presents a spectrum monitoring algorithm in support of that purpose for OFDM based CR ne...

zinc oxide (zno) nanopowders were synthesized by the sol–gel method from an ethanol solution of zinc sulfate heptahydrate in the presence of diethylene glycol surfactant. detailed structural and microstructural investigations were carried out using x-ray diffraction (xrd), high-resolution transmission electron microscopy (hrtem), field emission scanning electron microscopy (fe-sem), fourier tra...

Two vital challenges arise in the next generation 5G networks: scarcity of spectrum and the aspect of energy efficiency (EE). In this letter, we first formulate the prime issue, i.e., energy harvesting (EV) for 5G wireless networks, in which spectrum and energy resources are efficiently received and resourcefully managed. Thereafter, we introduce a medium access control (MAC) scheme for dual ti...

In this paper, we have proposed two novel plasmonic demultiplexing structures based on metal-insulator-metal surfaces which, beside their compact size, have a very good transmission spectrum. The impact of the key internal parameters on the transmission spectrum is numerically analyzed by using the twodimensional (2D) finite difference time domain (FDTD) method. The proposed structures could be...

We propose a Gaussian sampled fiber Bragg grating for multi-parameter sensing system. The sampled fiber Bragg grating combines the characteristics of fiber Bragg grating and long period grating. The transfer matrix method has been used to obtain the transmission spectrum of the grating. The shifts in narrowband loss peak and broadband loss peak in the transmission spectrum have been utilized to...