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The paper addresses simulation and fabrication technique to optimize a monofliar Helix antenna. A conducting wire in form of screw threads forms a Helix. Helix antenna is used in the field of space sciences due to its high directivity and gain. This paper optimizes the performance of a monofliar Helix antenna which is used as a feed at a frequency of 1420 MHz to study hydrogen line spectrum. This antenna can be used as a feed at frequency of 1420MHz. The theoretical simulations of helix are carried out using Numerical Electromagnetic Code, Version 2 software which is numeric code based on method of moments. Helix antenna is fabricated and optimized to a beam width ranging from 70-80°. Radiation properties, including far-field patterns, gain, axial ratio, VSWR, return loss are computed for frequency of 1420 MHz. All theoretical studies of helix antenna are carried out using NEC-2 (Numerical Electromagnetic Code, Version 2.0) software, which is a numerical code based on the method of moments. The measurements conducted in paper were limited to far-field patterns only. The helix with low fabrication cost makes this antenna very attractive to mobile and satellite communications and aerospace applications. [ABSTRACT FROM PUBLISHER]

Conventional beamformers are simple and robust but since their side lobe levels are high, they are susceptible to interference from undesired directions. In this paper a method of reducing the side lobe levels of a conventional beamformer using a combination of wavelet denoising and tapering is proposed. [ABSTRACT FROM PUBLISHER]

Photonic nanowires have recently been used to tailor the spontaneous emission of embedded quantum dots, and to develop record efficiency single-photon sources. We will present recent developments in this field mainly 1) the observation of a strong inhibition of the spontaneous emission of quantum dots in ultrathin photonic wires 2) the control of the linear polarization of the single photons by photonic wires with an elliptical section, 3) the joint observation (unlike-cavity-based devices) of a record high efficiency and pure single photon emission process in a photonic wire single photon source, 4) progress toward high-efficiency electrical-driven sources. [ABSTRACT FROM PUBLISHER]

As we consider the next set of challenges for pervasive heath, what are the issues that our current expertise may not sufficiently address? What might we have overlooked that should be on our research agenda as we go forward? In this brief paper, I argue that we would benefit from knowing more about how to design persuasive systems for single use situations (e.g., the decision to get a screening or vaccination) and that people can “graduate” from while maintaining healthy routines and habits they have developed. [ABSTRACT FROM PUBLISHER]

In this paper, an array of series fed antenna based on tapering patch width and through element is presented. The antenna has wide impedance bandwidth of 16.18% covering from 5.34 GHz to 6.28 GHz with a gain of 6.53 dBi. The use of through element technique reduces the overall length of array structure by 25.47%. It also has lower side lobe level, and wider impedance bandwidth compared to the past research. [ABSTRACT FROM PUBLISHER]

A hybrid long period fiber grating (HLPFG) sensor was utilized for sensing the refractive index and pressure for downhole applications. The HLPFG is fabricated by fattening and tapering on a single mode fiber, utilizing a standard fusion splicing and a CO2 laser, respectively. The limit of detection (LOD) of the HLPFG for the RI measurement in the range from 1.3150 to 1.3559 is 4×10−5 as a refractometer sensor which can be used for analysis of multicomponent in native petroleum. Pressure sensitivity of the HLPFG sensors in the range from 500 to 6000 psi is −0.6 pm/psi. With a 10 pm resolution for the wavelength shift detection our OSA, the LOD of the device at room temperature for pressure measurement is calculated to be 17 psi. This sensor can be used as a high pressure sensor in downhole application. [ABSTRACT FROM PUBLISHER]

Since the release by the Federal Communications Commission (FCC) of a bandwidth of 7.5GHz (from 3.1GHz to 10.6GHz) for ultra-wideband (UWB) wireless communication, UWB is rapidly advancing as a high data rate wireless communication technology. This paper focuses on UWB rectangular tapered microstrip patch antenna design with modification in ground plane to acquire UWB frequency range. Firstly the ground plane of microstrip patch antenna is cut to approximate L-shape with the optimization of feed line width and length to obtain the bandwidth from 3.73GHz to 7.67GHz. Later on by tapering the microstrip patch the ultra-wideband is obtained. Simulation result shows that the proposed UWB antenna have a bandwidth ranging from 3.4GHz – 10.6GHz which satisfies the system requirements for S-DMB, WIBRO, WLAN, CMMB and the entire UWB. [ABSTRACT FROM PUBLISHER]

Summary form only given. An experimental/theoretical research program is being established at the University of Wisconsin (UW) to study millimeter-wave, free-electron masers (FEMs). The program will concentrate on the investigation of devices using low-voltage (<100-kV), axially streaming, periodically focused electron beams and slow-wave structures. Topics of particular attention include efficiency optimization and average power handling enhancement in the above-mentioned devices. The use of sheet electron beams for increasing the power-handling capabilities of low-voltage FEMs is investigated. Dispersion relations and growth rates for dielectric liner and periodic gratings are evaluated. Nonlinear effects such as tapering, mode-competition, and beam space-charge-as well as beam quality-are quantitatively studied for their impact on efficiency optimization. Experimental research is conducted on a streaming beam experimental (SBX) facility, which is capable of operating in single-pulse (0.1-100-μs) burst, or CW mode and delivers beams of up to 50 kV and 2 A (with later upgrade to 75 kV) [ABSTRACT FROM PUBLISHER]