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Implementation of millimeter-wave passive components on low-resistivity silicon using narrow and thin film structures is discussed in this paper. Dielectric narrow films in the order of a few tens of micron thick and with lateral dimensions similar or smaller than the top signal trace are implemented on silicon wafer by a simple but innovative microfabrication approach to significantly improve performance...
A microstrip patch antenna has a simple geometry which is normally etched on a dielectric substrate to form a resonant cavity over the ground plane. Depending on the size of the patch various TMmn modes resonate in the cavity and the radiation occurs due to the fringing field at the patch edge. Because they are highly resonant structures their bandwidth is small and operation in a wider band or multiple...
The scattering by infinitely long cylinders is a classical two-dimensional electromagnetic problem that can, in principle, be solved numerically. Mei and Van Bladel [1] have formulated the problem for a conducting cylinder of arbitrary cross-section using integral equation formulations. They have then reduced these integral equations to a matrix equation to determine the surface currents, which are...
The radiation characteristics of cos nφ δ(z) current distributions on an infinitely long dielectric circular cylinder are investigated. Exact analytical solutions are presented for the fields resulting from such distributions. Numerical results obtained from the far field approximations to the exact solutions are given. The numerical results clearly indicate the effect of changes in the cylinder's...
The analysis of an arbitrary shape printed loop microstrip antenna is presented. The Green's function of the microstrip antenna is employed for formulating an integral equation for the current distribution on the printed loop which is then solved using a moment method. Design of various loop shapes for producing circularly polarized field will be presented.
An exact treatment using the boundary value method for solving the problem of scattering of a line source field or a plane wave by a perfectly conducting elliptic cylinder coated by a confocal dielectric elliptical shell is presented. For the line source excitation the total field is calculated, while for the plane wave excitation the echo width is obtained. Sample and interesting results for the...
The electromagnetic response of an arbitrarily polarized dipole source in the vicinity of a two-layer dielectric spherical object in a lossy medium is investigated analytically. A technique based on the dyadic Green's functions is employed to determine the fields in every region. The formulation can be applied to a wide variety of electromagnetic sources. Numerical results are presented in the near...
The basic principle of granularity of beam positions in phased array antennas is considered. It is shown that by adjusting the phase distribution of central elements a fine incremental step between adjacent beam positions can be obtained. The effect of adjusting the phase distribution of central or edge elements on the sidelobe level is also studied. For a given beam position, the variation of the...
The study of wave propagation along conductors located at or near a lossy planar interface is of interest in geoelectromagnetics for remote sensing applications as well as in the power engineering field for transmission line analysis. It is important to determine the effect of the interface on the propagation and radiation characteristics of the geometry, especially if it is highly lossy as in the...
Circularly polarized antennas are commonly designed using two different approaches: 1) by shaping the geometry, and 2) by dual excitation of linearly polarized antennas. The most common antennas of the first type are the helical antennas, where the radiation is due to a circulating electric current on the conducting wire of the antenna. The geometry of the antenna controls the polarization and as...
An approximate numerical method is developed to determine the electromagnetic wave scattering by imperfectly conducting objects located inside a lossy ground. The incident field of the exciting loop, which is located above the ground, is determined using the dyadic Green's functions for a half-space. The scattering problem is then formulated using the magnetic field integral equation of an unbounded...
The radiation field of a horizontal magnetic dipole located above a homogeneous lossy ground is formulated using the dyadic Green's functions. The resulting field vectors are then split into the primary and secondary components. The primary components represent those that would exist in the absence of the ground leaving the secondary components to represent the contribution of the ground. For different...
Accurate eigenvalues of nonzero-integer spherical wave functions of coaxial and biconical structures are determined for both TE and TM fields. It is found that the number of the eigenvalues is equal to the order of the characteristic equations, i.e., the order of the related associated Legendre functions and their derivatives. For each TE mode there is a unique nontrivial eigenvalue, which is the...
Microstrip antennas are highly resonant structures and, for simple patch configurations, the bandwidths of each mode is quite small. As an antenna, their most useful mode is the TM11 mode that radiates in the broadside direction with a good gain. All other modes, TMnm, radiate conical beams with a null in the broadside and have a pattern peak that moves towards the endfire direction by increasing...
The scattering of electromagnetic waves from axisynmetric bodies, partially coated with a thin metallic layer is considered. The aim is to study the general properties of the scattering process from such complex targets for which analytic and experimental results are needed, and also to investigate the effect of metallic coating on the radar signature of these targets. The scattering problem is formulated...
The radiation characteristics of conical reflectors with a line source feed in the form of an array of dipoles are derived using a numerical integration of the physical optics currents. Representative radiation patterns are computed and presented.
Eggimann [1] has suggested that a circular array of ferrite cylinders surrounding an electric line source might shift its main lobe by varying the applied magnetic field. Later, Okamoto [2] presented a numerical method for solving the two dimensional problem of scattering by multiple gyrotropic cylinders. He then showed by numerical results the possibility of beam scanning by a circular array of plasma...
Thin film copper membranes on silicon substrates were constructed using micromachining techniques. Membranes were used as flexible ground planes beneath a microstrip transmission line. Actuation of membranes induced phase shift in the transmitted signal. Membranes possessed radial surface corrugations 10 μm deep to increase their flexibility. Membranes were released using a combination of KOH and...
Recently, there has been extensive research on the photonic band gap structures (PBG's) and their applications in the microstrip antennas and transmission lines. The PBG structures have the unique property of preventing the propagation of EM waves in certain directions for certain frequencies. The properties of these structures are defined by the shape, size, symmetry and, the constituent material...
Microstrip antennas are known for their advantages in lightweight, low volume, low cost, and compatibility with integrated circuits. These advantages make this antenna a useful candidate in applications such as mobile radio, satellite communications, biomedical radiators and feed elements for reflectors. An important factor in the performance of microstrip patch antennas is the ground plane. The size...
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