Antenna arrays yield multiple, simultaneous available beams. These beams can be made to have high gain, low side lobes and controlled beam width. In conventional beam forming, the smallest beam width depends on the geometric dimensions of the receiving array. This problem may overcome by the Hyper beam invention. The linear array when implemented using Hyper beam technique, there is a considerable reduction of side lobes and beam width compared to the conventional beam forming. As a result, the relevant equations pertaining to normal linear array and the Hyper linear array are presented. The effect of the Hyper beam exponent on the beam patterns are shown.
In this paper a new background subtraction algorithm was developed to detect moving objects from a stable system in which visual surveillance plays a major role. Among all existing algorithms it was choosen because of low computational complexity which is the major parameter of time in VLSI. The concept of the background subtraction is to subtract the current image with respect to the reference image and compare it with to the certain threshold values. Here we have written the core processor Microblaze is designed in VHDL (VHSIC hardware description language), implemented using XILINX ISE 8.1 Design suite the algorithm is written in system C Language and tested in SPARTAN-3 FPGA kit by interfacing a test circuit with the PC using the RS232 cable. The test results are seen to be satisfactory. The area taken and the speed of the algorithm are also evaluated.
This article presents a novel high gain rotated circular patch antenna operating at S-band. Circular patches are arranged with probe feeding in a particular order to get circular polarization. By employing sequential rotation technique, the proposed antenna is giving an impedance bandwidth of more than 40% (return loss less than-10 dB) and 3dB axial ratio bandwidth of 15% in the operating band with peak gain around 13 dB. Array antenna is fabricated on RT-duroid substrate and the measured results are showing good agreement with the simulation results.
Number of investigations done to reduce the size of the microstrip patch antennas at a fixed operating frequency. In general microstrip antennas are half wavelength structures and are operated at the fundamental resonant mode TM01 or TM10. To reduce the size without disturbing the substrate material permittivity value we are having some special techniques like shorting pin, shorting plate, shorting wall and some other slot models. This paper describes the design and simulation of planar inverted folded antenna with shorting plate model on the liquid crystal substrate material. The present study includes verification of radiation patterns, return loss and field distributions. The operating frequency is chosen 2.4GHz for Bluetooth applications. All the output parameters are simulated using commercial Ansoft-HFSS Software.
In this paper we presented the design and analysis of Bow-Tie antenna on liquid crystal substrate, which is suitable for the Bluetooth/WLAN-2.4/WiBree/ZigBee applications. The Omni-directional radiation patterns along with moderate gain make the proposed antenna suitable for above mentioned applications. Details of the antenna design and simulated results Return loss, Input impedance, Radiation Patterns, E-Field, H-Field and Current Distributions, VSWR are presented and discussed. The proposed antenna is simulated at 2.4 GHz using Ansoft HFSS-11.
This article describes the analysis and design of the excitation schemes of the plasmonic angular ring resonator-based band-pass filters using a metal-insulator-metal (MIM) waveguide. The excitation schemes of the plasmonic angular ring resonator-based band-pass filters have been analyzed in terms of their physical length by using commercially available electromagnetic full-wave simulation software (CST microwave studio). The excitation schemes of the plasmonic angular ring resonator-based band-pass filter using a MIM waveguide have been realized at the optical O (1260–1360 nm) and U (1625–1675 nm) bands, respectively, as it has dual-band characteristics. The excitation schemes of the plasmonic angular ring resonators have been designed and simulated to determine the variation in transmission and reflection coefficients. The magnetic field distribution of the proposed filters was observed. The ring resonators require low power and had a compact size, which was further used for the development of photonic integrated circuits (PICs). The applications of these resonators are further extended and they are used in the development of antennas, branch line couplers, directional couplers and diplexers.
Cognitive radio (CR) is a new technology that is proposed to improve spectrum efficiency by allowing unlicensed secondary users to access the licensed frequency bands without interfering with the licensed primary users. As there are several methods available for spectrum sensing, the energy detection (ED) is more popular due to its simple implementation. However, ED is more vulnerable to the noise uncertainty so for that reason, we present a robust detector using signal to noise ratio (SNR) with dynamic threshold energy detection technique is combined with the kernel principal component analysis (KPCA) in Cognitive Radio Networks (CRN). The primary purpose of kernel function is to ensure that its dependency relies on inner-product of data without the feature space data requirement. In this paper, with the aid of kernel function the spectrum sensing with the leading eigenvector approach is modified to a feature space of higher dimensionality.By introducing of efficient detection system with dynamic threshold facility helps the better detection levels even low SNR values with quite a lot of noise uncertainty levels. The simulation results of the proposed system reveal that KPCA outperforms with that of traditional PCA in terms of false alarm rate, detector performance when tested under various uncertainties for orthogonal frequency division multiplexing signal.
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