L. Palumbo

Bio: L. Palumbo is an academic researcher from CERN. The author has contributed to research in topics: Flange & Directional antenna. The author has an hindex of 3, co-authored 3 publications receiving 54 citations.

A uniform asymptotic expansion of a typical diffraction integral with many coalescing simple pole singularities and a first-order saddle point

Abstract: The asymptotic evaluation of a typical diffraction integral with many coalescing simple pole singularities and a first-order saddle point is examined. A uniform solution is obtained by means of the Taylor expansion.

Parabolic antennas with a loaded flange

Abstract: The radiation characteristics of a parabolic dish with a loaded peripheral flange are examined in detail in order to assess the effectiveness of such a loading in further reducing the backward scattered field. Uniformly valid diffraction coefficients are developed to deal with both isotropic and anisotropic surface impedances. It is shown that substantial improvement of the antenna performance can be obtained in a wide rear angular sector, and the optimal loading conditions are determined.

Flanged parabolic antennas

Abstract: The radiation characteristics of symmetric parabolic antennas with a peripherical flange are examined in detail in order to assess the effectiveness of such a flange in reducing the backward scattered field. It is shown that the best behavior is obtained by using a right-angled flange, which allows achievement af a significant field level reduction in a wide rear angular sector, without affecting the field radiated in the forward directions.

A subspace rotation approach to signal parameter estimation

Abstract: A new approach to Estimation of Signal Parameters by Rotational Invariance Techniques (ESPRIT) is described in the context of direction-of-arrival estimation, but is also applicable to other problems The method relies on finding the underlying rotation between the common subspaces associated with an array of pairwise-matched and codirectional sensor doublets ESPRIT has several remarkable advantages over earlier techniques such as MUSIC, and also provides asymptotically unbiased and efficient estimates

Radome attachment band clamp

Abstract: A band clamp for coupling a radome to a distal end of a reflector dish for improving the front to back ratio of a reflector antenna, is provided with an inward projecting proximal lip and an inward projecting distal lip. The distal lip is dimensioned with an inner diameter equal to or less than a reflector aperture of the reflector dish. The proximal lip may be provided with an inward bias dimensioned to engage the reflector dish in an interference fit and/or turnback region dimensioned to engage an outer surface of a signal area of the reflector dish in an interference fit. A variety of different configurations of protruding portions extending from the band clamp may be applied to further improve electrical performance.

Reflector antenna radome attachment band clamp

Abstract: A band clamp for coupling a radome to a distal end of a reflector dish for improving the front to back ratio of a reflector antenna, the band clamp provided with an inward projecting proximal lip and an inward projecting distal lip. The distal lip dimensioned with an inner diameter equal to or less than a reflector aperture of the reflector dish. The proximal lip provided with a turnback region dimensioned to engage an outer surface of a signal area of the reflector dish in an interference fit. A width of the band clamp may be dimensioned, for example, between 0.8 and 1.5 wavelengths of an operating frequency.

Electromagnetic diffraction of an obliquely incident plane wave field by a wedge with impedance faces

Abstract: A uniform asymptotic solution is presented for the electromagnetic diffraction by a wedge with impedance faces and with included angles equal to 0 (half-plane), pi /2 (right-angled wedge), pi (two-part plane) and 3 pi /2 (right-angled wedge). The incident field is a plane wave of arbitrary polarization, obliquely incident to the axis of the wedge. The formal solution, which is expressed in terms of an integral, was obtained by the generalized reflection method. A careful study of the singularities of the integrand is made before the asymptotic evaluation of the integral is carried out. The asymptotic evaluation of the integral is performed taking into account the presence of the surface wave poles in addition to the geometrical optics poles near the saddle points. This results in a uniform solution which is continuous acros the shadow boundaries of the geometrical optics fields as well as the surface wave fields. >

High-frequency scattering from a wedge with impedance faces illuminated by a line source. I. Diffraction

Abstract: The canonical problem of evaluating the scattered field at a finite distance from the edge of an impedance wedge which is illuminated by a line source is considered. The presentation of the results is divided into two parts. In this first part, reciprocity and superposition of plane wave spectra are applied to the left far-field response of the wedge to a plane wave, to obtain exact expression for the diffracted field and the surface wave contributions. In addition, a high-frequency solution is given for the diffracted field contribution. Its expression, derived via a rigorous asymptotic procedure, has the same structure as that of the uniform geometrical theory of diffraction (UTD) solution for the field diffracted by a perfectly conducting wedge. This solution for the diffracted field explicitly exhibits reciprocity with respect to the direction of incidence and scattering. >