High-frequency analysis of a semi-infinite array of line sources (original) (raw)
Related papers
2010
The accurate electromagnetic analysis of artificial periodic surfaces formed as planar layers with complicated periodic metallization patterns, having a grid period much smaller than the effective wavelength (densely periodic), is important for the design and analysis of a variety of electromagnetic structures. However, full-wave modeling can be extremely time-consuming and computationally expensive, especially for aperiodic sources in close proximity to periodic surfaces. In this paper, we describe approximate homogenized models for a Green's function that treats planar patterned screens (grids) as quasi-dynamic homogenized impedance surfaces and dielectric layers in a fully dynamic manner. The resulting Green's functions are only slightly more complicated than those for dielectric layers without metallization and can be numerically computed using standard methods for layered media. We restrict attention to line sources and compare numerical results from this method with those from a full-wave array scanning method, which is more complex analytically and much more demanding to evaluate numerically. Very good agreement is found between the two methods except for source and/or field points extremely close to the metallization layer, confirming the accuracy of the homogenized representations of periodic surfaces for near-field sources.
Propagation of High-Frequency Current Waves Along Periodical Thin-Wire Structures
2006
The homogeneous problem of propagation of current along a thin wire of arbitrary geometric form near the ground by the using of the Full-wave Transmission Line Theory [1-3] is reduced to a Shrödinger-like differential equation with a "potential" depending on the geometry of the wire and on frequency. This "potential" is a complex -valued quantity that corresponds to radiation losses in the initial electrodynamics problems or corresponds to absorption of the particles in the quantum mechanic analogy. If the wire structure is quasi periodical (i.e., it consists from a finite number of identical sections), the "potential" can be approximately represented as a set of periodically arranged identical potentials. We use a formalism of transfer matrix and find an analytical expression for the transmission coefficient of the finite number of periodically located non-uniformities which also contains the scattering data for one non-uniformity. The obtained result gives the possibility to investigate forbidden and allowed frequency zones which are typical for periodic structure.
IEEE Access
In this paper, we explore the excitation of magnetic current surface waves in truncated periodic arrays of slots in a conducting screen. A specialized Method of Moments (MoM) implementation is presented, which makes it possible to efficiently solve the scattering problem involving truncated arrays of several thousands of slots. By making use of the dispersion diagrams of surface waves propagating along infinite periodic arrays of slots, we are able to explain the absence of magnetic current surface waves in the arrays at frequencies in the neighborhood of the transmission peak associated to the slots natural resonances (length roughly equal to half the wavelength), while they are present when the arrays are excited under extraordinary transmission (EOT) conditions. In order to experimentally check this different behavior, an aluminium plate periodically perforated with slots has been fabricated and fed by means of a pyramidal horn, and the electric field behind the plate has been measured with a planar near-field system at a few centimeters from the plate. Our experimental results and MoM simulations agree, demonstrating the presence of a standing wave pattern of magnetic current surface waves at the EOT frequency, and the absence of surface waves at the slots natural resonant frequency.
The homogeneous problem of current propagation along a thin wire of arbitrary geometric form near ground is reduced use of the Full-Wave Transmission Line Theory [8-10] to a Schrödinger-like differential equation, with a "potential" depending on both the geometry of the wire and frequency. The "potential" is a complex -valued quantity that corresponds to either radiation losses in the framework of electrodynamics or to the absorption of particles in the framework of quantum mechanics. If the wire structure is quasi periodical, i.e., it consists of a finite number of identical sections, the "potential" can be approximately represented as a set of periodically arranged identical potentials. We use the formalism of transfer matrices and find an analytical expression for the transmission coefficient of the finite number of periodically located non-uniformities which also contains the scattering data of one nonuniformity. The obtained result yields the possibility to investigate forbidden and allowed frequency zones which are a typical feature of periodic structure.
A contribution to the theory of electromagnetic induction of a line source
Studia Geophysica Et Geodaetica, 1976
Formulae for the magnetic" fieM intensity of a harmonic line source are derived on the basis of an integralJbrmulation of the induction law. This approach made it possible-in a natural way-to give a mathematically exact description of the line source, as well as all the field properties. The most complicated case when the line source lies on the boundary between two media is examined in detail. The resultant formulae have been derived with regard to the ,fact that they make the effective computation of the field values in the whole space possible.
Full-wave analysis of a large rectangular array of slots
1998
Large, finite arrays are often studied in hypothesis of infinite structure, thus allowing the reduction of the numerical effort to that of a single periodic cell. Sometimes this approximation leads to reasonable results in predicting the input impedance of elements far out from the edges. However, for near edge elements it is visibly wrong. Furthermore, when wide beam angle scanning occurs, the effects of truncation can be relevant also for elements very far from the edges. A truncated Floquet waves (TFW) method has been presented, for predicting the distributions of the radiating currents, including those belonging to the edge elements of the array, while retaining a number of unknowns which is comparable with that occurring for the infinite array problem. This approach is based on the method of moments (MoM) solution of an integral equation in which the unknown function can be interpreted as due to the edge diffracted field excited by the Floquet waves of the infinite structure. In this paper, the formulation of the TFW method is applied to the 3D case of rectangular array of slots in an infinite ground-plane.
Propagation of Current Waves along Quasi-Periodical Conductors
The homogeneous problem of current propagation along a thin wire of arbitrary geometric form near ground is reduced use of the Full-Wave Transmission Line Theory [8-10] to a Schrödinger-like differential equation, with a "potential" depending on both the geometry of the wire and frequency. The "potential" is a complex -valued quantity that corresponds to either radiation losses in the framework of electrodynamics or to the absorption of particles in the framework of quantum mechanics. If the wire structure is quasi periodical, i.e., it consists of a finite number of identical sections, the "potential" can be approximately represented as a set of periodically arranged identical potentials. We use the formalism of transfer matrices and find an analytical expression for the transmission coefficient of the finite number of periodically located non-uniformities which also contains the scattering data of one nonuniformity. The obtained result yields the possibility to investigate forbidden and allowed frequency zones which are a typical feature of periodic structure.