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The boundary value solution of electromagnetic radiation from an axis-asymmetric slot antenna on a perfectly conducting prolate spheroid coated with a confocal sheath is presented. The electromagnetic fields are expanded in terms of prolate spheroidal vector wave functions. The unknown expansion coefficients are determined from a set of linear equations derived from the application of boundary conditions on the tangential fields' components. Numerical results for radiation patterns and power are presented. It is found that the thickness of the sheath has a significant effect on the radiated fields, and the radiated power is greatly enhanced for certain values of the sheath thickness. [ABSTRACT FROM AUTHOR]

Continuous current spectrum of an integrated open waveguide structure is identified as the branch cut contribution to singularity expansion of those currents in the complex axial transform plane. Those singularities in that plane include poles associated with the guiding structure and branch points contributed by layered background environments. The manner in which singularities in background environments manifest themselves as branch points in the complex axial transform plane is reviewed. Based on spectral integral equation formulation, approximate and analytical expression for spatial microstrip current is obtained. That approximation is based on Maxwellian distribution for the transverse current profile. This result is the representation of currents in terms of proper propagation mode spectrum. During the integration around branch cuts, singularities in the transverse transform plane migrate in a complicated manner. The trajectories of this migration are identified and suitably accommodated during the real axis integration in that plane. This overall procedure leads to a decomposition of the total currents into bound modes and continuous spectrum contributions. This representation is validated by real axis integration in the axial transform plane. The quasi TEM characteristic impedance of bound mode is calculated and validated by comparison with well-known empirical formula. [ABSTRACT FROM AUTHOR]

Proposes a single-feed triangular microstrip patch antenna that can be operated at two distinct resonant modes. Ability of the two resonant modes to radiate an omnidirectional dipole-like pattern with linear polarization and a broadside pattern with circular polarization, respectively; Study of several designs of the proposed antennas with different substrate thickness and patch sizes to achieve the required frequency ratio of the two operating frequency bands.

A new application for the high-resolution processing algorithm MUSIC, applied to a rotating antenna, is presented. Experimental results show that significant improvement can be achieved using the proposed method, compared to a low-directivity rotating antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 329–330, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10909 [ABSTRACT FROM AUTHOR]

Wireless solutions are rapidly growing in machine-to-machine communications in industrial environments. These environments provide challenging conditions in terms of radio wave propagation as well as electromagnetic interference. In this article, results from the characterization of radio channel properties are summarized in order to provide some guidelines for the choice of wireless solutions in industrial environments. In conclusion, it is essential to know the sensitivity of industrial processes to time delay in data transfer. Furthermore, it is important to be aware of the radio interference environment and the manner in which different wireless technologies react upon interference. These steps will minimize the risk of unforeseen expensive disturbances in industrial processes. [ABSTRACT FROM PUBLISHER]

The joint winner of the Rishbeth Prize at the NAM in Belfast this year was “How do solar wind compressions affect the pulsing and intensity of Saturn kilometric radiation?” by Sarah V Badman with Stan W H Cowley, Laurent Lamy, Baptiste Cecconi and Philippe Zarka. Sarah Badman writes. Saturn emits bursts of radio waves from its polar regions as it rotates. This study examines how the solar wind affects the intensity and periodicity of the radio bursts. The results not only show how Saturn's magnetosphere interacts with the solar wind, but they also provide a framework for understanding radio emissions from extrasolar planets and pulsars. [ABSTRACT FROM AUTHOR]

A method is presented which simulates the acoustic wave-field in the atmosphere using a Chebyshev pseudo spectral approach. The aero-acoustic equation of motion is solved in spherical coordinates. The computational time is significantly reduced by applying a rotationally symmetric approximation. Since the complete wave-field is calculated for the two-dimensional model the solution provides pictures of the pressure propagation from the source to the receiver. These images make it possible to study two effects in detail: How the sound and wind profiles affect the synthetic barograms for a fixed source, and in which way the source in space and time is reflected in the synthetic recordings for a stationary elastic model. Examples for both applications are shown where measured data are compared with synthetics. The recording at the German IMS station I26DE of the September 21, 2001, chemical explosion in Toulouse is considered as a benchmark for synthetic barograms calculated for two-dimensional profiles based on NRL-G2S and MSISE/HWM. In the second example the estimation of the source functions of super-sonic moving bodies is demonstrated. The synthetic waveforms are compared with the signals of two bolides recorded at the French IMS station I24FR at Tahiti from the December 1, 2003. [ABSTRACT FROM AUTHOR]