Presence Of Ground Plane Research Articles

Characteristic Mode Analysis of Mutual Coupling

Mutual coupling between neighboring antennas is a major concern in the array design. Using the concept of characteristic modes, this work proposes a theoretical framework for the analysis of such electromagnetic interaction and its control mechanism. The root of interelement coupling lies in the mutually induced current in the neighboring elements. Henceforth, the initial part of this work concentrates on computing the coupled current by modeling the interaction of the uncoupled modes. Closed-form formulations have been derived for quantifying the coupling impacts. The proposed formulations have been further verified with numerical examples and method of moment-based commercial solver, such as Antenna Toolbox. Later, the theory of substructure modes has been combined with the theory of coupled characteristic modes to understand the perturbation in coupling behavior in the presence of ground plane or a parasitic element. A design strategy has been suggested to optimize the shape of the intermediate parasitic structure for controlling the coupled current in the neighboring elements. This current-based approach can find applications in different coupled scenarios such as antenna arrays or in printed circuit board components.

Beam reconfiguration of linear array of parallel dipole antennas through switching with real excitation voltage distribution

In this paper, authors propose a method based on the modified particle swarm optimization (PSO) for beam reconfiguration of linear array of mutually coupled parallel half-wavelength dipole antennas with real excitation voltage amplitude distribution. Two different beam pairs are generated, one pencil/pencil beam pair and another pencil/flat-top beam pair in the horizontal plane. One beam is changed to another through switching while sharing a common amplitude distribution. Two examples are presented, one without ground plane and another in presence of ground plane. Dipoles are connected to its feed network through a switch, so that it can be turned on or off, depending on the switch position. Beam reconfiguration is achieved by suitably turning the array elements on or off using same voltage excitation distribution. Modified PSO is used to compute the excitation voltages as well as the switching configuration for each pattern having a prefixed side lobe level. The current in the driven and parasitic elements is determined via induced EMF method considering the current distribution on each dipole to be sinusoidal. Proposed method efficiently synthesizes dual-beam switching the power pattern from pencil to pencil and pencil to flat-top having same or different side lobe levels using common excitation voltages. It calculates the maximum variation of the active impedance of driven elements and the power losses when the radiation patterns switch from one beam to another. The paper calculates the array directivity as the distances between antenna array and the ground pane varies. Three other state-of-the-art metaheuristics like differential evolution, gravitational search algorithm, artificial bee colony algorithm are also employed for achieving a comparative evaluation.

Screening and dissipation at the superconductor-insulator transition induced by a metallic ground plane

We study localization phenomena in two dimensional systems of charged particles in the presence of a metallic ground plane with particular focus on the superconductor-insulator transition. The ground plane introduces a screening of the long-range Coulomb interaction, and provides a source of dissipation due to the gapless diffusive electrons. The interplay of these two effects leads to interesting physical phenomena which are analyzed in detail in this paper. We argue that the generic superconductor-insulator transition of charged particles in the presence of the ground plane may be controlled by a fixed line with variable critical exponents. This is illustrated by an explicit calculation in an appropriate e expansion. In contrast, the universal properties of the superconductor-Mott insulator transition in the clean limit at commensurate densities are shown to be unmodified by either the metal or the long-range Coulomb interaction. A similar fixed line can arise in the presence of a metallic ground plane for quantum Hall plateau transitions. Implications for experiments on Josephson-junction arrays and quantum Hall systems are described.

Study of a printed meander antenna using the FDTD method

AbstractA printed meander antenna is studied using the FDTD method. The influence of a number of antenna parameters (dielectric constant, substrate thickness, and presence of ground plane) on the input impedance and radiation pattern of the antenna is examined. It is found that a 60% size reduction compared to a half‐wave dipole can be achieved with a substrate dielectric constant of 4. Data presented can be used to design antennas with resonant resistances of 40Ω or higher. A similar study of an antenna on a dielectric slab is also performed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 440–444, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10943

Investigation of a test methodology for triboelectrification

Parameters governing charging due to triboelectrification are reviewed and equations developed to model the rate of net charge buildup and the resulting net charge for typical situations. The net charge is a function of the materials in contact, area, the environment, and dissipation processes which depend on the ambient conditions, the materials and the presence of ground planes. To evaluate the triboelectrification phenomenon, an in situ test method must be capable of determining the saturation charge density levels possible for the materials under test in a particular engineering application. Results are presented for a sphere-plane geometry which is used to study the effect of temperature and relative humidity on the net charging due to triboelectrification.

Influence of a ground plane on the ESD event in electronic systems

Capacitance coefficients were measured for a basic two-conductor system, simulating the approach of a charged object (the human body) to a second object which can be floating or grounded (the equipment under test). Parameters studied include the size of the conductors, their separation, and position relative to vertical and horizontal ground planes. System equations, based on Maxwell's technique, are solved to yield the body potentials and a relative probability of discharge for the various configurations. The presence of ground planes is shown to increase the ESD (electrostatic discharge) susceptibility of small floating bodies. The results provide a better understanding to the ESD event and demonstrate the importance of ground planes in electrostatic discharge test methods. >

Design of a High Performance DIP-Like Pin Array Package for Logic Devices

Pin array packages offer package sizes which are much smaller than their dual in-line package (DIP) equivalent. Pin array packages are also through hole mountable. A pin array package is described which is DIP-like in that it is rectangular but the input/ output (I/O) pins do not fully populate its base. The package is a co-fired tungsten metallized multilayer ceramic package with 104 I/O's yet is only 1.16 in wide by 1.88 in long. Dual tier wire bond ledges are used to minimize wire bond lengths which also enhances electrical performance. This package is used in systems where many leads must switch simultaneously onto a heavily loaded bus. Such switching may result in considerable electrical noise. To meet noise requirements the package had to have the lowest possible ground impedance. This was accomplished by dedicating 20 percent of all pins to power and ground and by strategically positioning them on the package. Power and ground planes were also placed within the layered ceramic package to further lower the ac ground impedance. Finally, these planes were arranged to provide nearly 1000 pF highquality built-in filter capacitance. Noise is further reduced by minimizing crosstalk within the package. The presence of ground planes helps lower interlead crosstalk by factors of three to ten. Resistance and capacitance loading of the signal paths are designed to be acceptably low. A simple packaging change allows all the signal nets to be electrically probed from the top of the package. The package, depending upon its configuration and use of heat sinks, also has the capability of handling high power integrated circuits (IC's).