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4 Journal of Telecommunications and Information Technology

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Analytical Investigation on a New Approach for Achieving Deep Penetration in a Lossy Medium: The Lossy Prism

100%

Frezza F. , Simeoni P. , Tedeschi N.

Journal of Telecommunications and Information Technology

2017

tom nr 3

17--24

Recent studies highlighted deep-penetration prop-erties of inhomogeneous waves at the interface between a loss-less and a lossy medium. Such waves can be generated bymeans of radiating structures known as Leaky-Wave Anten-nas (LWAs). Here, a different approach is proposed basedon the use of a lossy prism capable to generate an inhomo-geneous wave when illuminated by a homogeneous wave. Thelossy prism is conceived and designed thinking of Ground-Penetrating Radar (GPR). The results achieved by the lossyprism will be compared with those obtained by means of a pre-viously designed LWA that was created with the identical ob-jective. The approach of this paper is purely theoretical, andit aims at providing basic ideas and preliminary results usefulfor an innovative LWA design.

The Optimum-efficiency Beam Multiplier for an Arbitrary Number of Output Beams and Power Distribution

100%

Frezza F. , Marciniak M. , Pajewski L.

Journal of Telecommunications and Information Technology

2017

tom nr 3

94--98

This paper deals with phase gratings working in the paraxial domain. The profile of the optimum-efficiency beam multiplier with an arbitrary number of output diffraction orders is derived in an analytic form by exploiting methods from the calculus of variation. The output beams may be equi-intense or with arbitrary distribution of power. Numerical examples are given for different values of the number of output beams.

Numerical Evaluation of Electromagnetic-wave Penetration at Normal Incidence through an Inhomogeneous-wave Approach

100%

Calcaterra A. , Frezza F. , Simeoni P. , Tedeschi N.

Journal of Telecommunications and Information Technology

2018

tom nr 2

76--86

This paper presents numerical scenarios concerning penetration in a lossy medium that can be obtained by radiating inhomogeneous electromagnetic waves. Former papers approached this problem, both analytically and numerically, ﬁnding requirements and limits of the so-called “deeppenetration” condition, which consists of a wave transmitted in a lossy medium having an attenuation vector whose direction forms the angle of ninety degrees with the normal to the separation surface. The deep-penetration condition always requires an oblique incidence, therefore is not practical in many applications. For this reason, we are interested here in ﬁnding whether an inhomogeneous wave guarantees larger penetration than the one obtainable with homogeneous waves, even when the incident wave is normal to the separation surface between two media, i.e. when the deep-penetration condition is not satisﬁed. We are also interested in verifying numerically whether the lossy-prism structure may achieve larger penetration than the one obtainable through traditional leakywave antennas, and we also wish to propose a lossy-prism design more realistic than the one previously presented in the literature.

Experimental Analysis of a Directive Antenna with a 3D-EBG Superstrate

88%

Pajewski L. , Frezza F. , Marciniak M. , Piuzzi E. , Rossi G. V.

Journal of Telecommunications and Information Technology

2017

tom nr 3

113--124

A three-dimensional electromagnetic crystal is employed as a directivity-enhancing superstrate for planar antennas. The crystal is a woodpile made of alumina rods. In a shielded anechoic chamber, the performance of a patch antenna covered with the woodpile is measured. The superstrate is positioned at different distances from the antenna and its orientation is varied in the 8–12 GHz frequency range. The return loss, gain and radiation pattern in the E- and H-planes are measured. The electromagnetic behavior of Fabry-Perot cavities with woodpile mirrors, equivalent to the compound radiator, is also studied. The main effect of the crystal on the antenna performance is an enhancement of about 10 dB in maximum gain. A rather complete series of experiments is presented, highlighting the role of the periodic structure in the directivity enhancement and allowing a deeper understanding of the electromagnetic phenomena involved in EBG resonator antennas. Benefits and disadvantages of this kind of antennas are discussed and ideas for future research are given.