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A target recognition system based on scattering centers extracted using ESPIRIT is investigated in this study. The scattering extraction approach is first tested on a synthetic target then applied to real radar targets with real radar data. The performance of the recognition system is evaluated under various adverse conditions.
The scattering of a plane wave from a dielectric grating loaded with a high refractive index layer is treated by the perturbation method and the scattered field is analytically derived. An ordered waveguide system composed of identical cores of equal space is used as a dielectric grating. The complex power of the total field is calculated and it is shown that the complex power is continuous at the...
Analytical manipulations on the Volume Electric Field Integral Equation (VEFIE) are performed for cloaking dielectric volumes (with maximum dimension D) from incoming fields (with wavelength λ). Three main mathematical conditions are derived for any frequency regime (D/λ). The first confirms plasmonic cloaking in quasi-static regime; the second demonstrates plasmonic cloaking beyond the subwavelength...
The high-frequency asymptotic procedure developed for the diffraction by an elongated body is reduced to a mathematically correct boundary-value problem for a parabolic equation. The analogue of “time” η varies on an interval [−1, 1]. The problem is considered in the class of functions with not too singular behavior near η = ±1 and the solution is understood in the frame of limiting absorption principle...
This paper presents a method for noncontact estimation of rats sleep-wake stages based on the analysis of a bioradar signal. The method was validated utilizing data of the rat, which underwent sleep study in a laboratory of Neuroontogenesis of Institute of Higher Nervous Activity and Neurophysiology of RAS. For the animal a bioradar signal was recorded during 48 hours. We achieved Cohen's kappa of...
A novel design of dual-band and dual-sense circularly polarized slot antenna with asymmetric CPW feed and asymmetric U-shape signal line is presented. A rectangular patch above the signal line helps to get circular polarization in the lower band. Axial ratio bandwidth is significantly enhanced in the lower band by using a strip above the parasitic element. By adding a meandered grounded stub, circular...
Additive manufacturing is an interesting technique for the manufacture of intricate parts. This paper gives an introduction the 3D screen printing which might be well suited to make small scale metal antenna parts on a mass production basis.
The methods generally considered for the diffraction by a wedge with curved faces are often different as you consider a wedge of narrow or large angle. An original approach, initiated in [1,2] for faces of constant curvatures and whose results have been used by Borovikov in [3] for his developments on non constant curvature case, permits a new global asymptotic study for an impedance curved wedge...
The Sommerfeld-Maliuzhinets inversion theorem has opened a new way of investigation on diffraction by a wedge-shaped domain, in the large class of canonical problems in frequency and time domains. In this frame, we review here some general representations of spectral function attached to total field and their properties.
This paper deals with the phenomenon of runaway electrons generation in fast discharges under atmospheric pressures. For the first time we explain the existence of runaway electrons having so-called “anomalous” energies (above the applied voltage value) according to physical kinetics principles. The model we consider provides comprehensive information on the formation and development of runaway electron...
The problem of high-frequency diffraction by a strongly elongated body is considered. The surface is supposed to be well approximated by a spheroidal surface. The asymptotic approximation for the induced currents is constructed by means of the parabolic equation method under the assumption that the wave-size of the body in the longitudinal direction is of the order of the square of its wave-size in...
A time domain integral relation of the transfer coupled response between antennas in close proximity is derived based on an electromagnetic reciprocity relation. Closed form expression of the integration relies on convenient representation of the Green function propagator. Using alternative representations of the propagator facilitates a review of the different characteristics of the coupled response...
The isotropic transmission cross sections of loaded and unloaded apertures have been studied. Results from numerical calculations as well as measurements are presented for three different load configurations, consisting of an absorber frame surrounding the aperture on either both or only one side. Presented results shows that, with a carefully designed absorber frame, the total transmitted power can...
This paper deals with the evaluation of the time domain electric field, which is diffracted by a perfect electrically conducting / lossless dielectric composite structure consisting of two adjacent acute-angled wedges with the edge in common. The involved diffraction coefficients are determined by applying the inverse Laplace transform to the corresponding Uniform Asymptotic Physical Optics diffraction...
Even though there has been excellent progress in terahertz systems for scientific applications, mature imaging systems operating above W-band (75–100 GHz) has been lacking. This ‘THz radar gap’ provides an opportunity for imaginative scientific, commercial, and security applications. Terahertz radars provides several benefits over either shorter or longer wave bands, such as large absolute bandwidth...
A novel inherently passive and convergence accelerated Foster-type circuit model for non-uniform, radiating transmission lines (TLs) is presented. The straightforward derivation is based on the solution of TL equations by an eigenvector expansion. Modal conductances consider radiation losses, calculated from the radiated power of modal far fields. So far not found in the literature, the definition...
Diffusion equation based modeling has been proposed for mapping the reverberant component of the electromagnetic field in enclosures at high frequencies. Preliminary evaluation of the electromagnetic diffusion model using a dimensional reduction approach showed promising results compared to measurements. Here we develop a full three-dimensional diffusion model of the experimental canonical test cases...
Transmission lines are used to deliver power flow of electromagnetic wave with little dissipating loss due to non-radiated symmetrical structures. With the motivation of new design recipe of series-fed antenna arrays, transmission lines are engineered for radiation by breaking the field symmetry. Here, in this paper, we have summarized several strategies to break the field symmetry of typical transmission...
Near-zero index metamaterials play an important role in wave-matter interactions, exhibiting several promising techniques to control and manipulate fields and waves. In this paper, we study the scattering properties of the epsilon-and-mu-near-zero metamaterials. By immersing a non-magnetic dielectric rod within the epsilon-near-zero host, we can imitate the far-field scattering pattern of epsilon-and-mu-near-zero...
This paper discusses an new technique of breast microwave imaging based on combined use of video-tracker and subsurface radar. The feasibility study of the proposed method is done by both mathematical simulation and experiments. A back projection technique used for data processing proved to be reliable while reconstructing microwave images of a breast phantom with a dialectically contrast inclusion...
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