Effect Of Ground Plane Research Articles

Quasistatic analysis of broadside-coupled conductor-backed asymmetric coplanar waveguide with one lateral ground plane using conformal mapping method

CAD-oriented analytic formulas for calculating the quasistatic TEM parameters of a broadside-coupled conductor-backed asymmetric coplanar waveguide (BC CBACPW) with one lateral ground plane are obtained using the conformal mapping method, which can provide accurate and fast calculations. The effect of a single lateral ground plane on the mode velocity ratio and coupling coefficient are presented and discussed. The accuracy of the closed-form expressions has been confirmed by comparison with results available in the literature for a general broadside-coupled CPW. Also, it is shown that the new structure has a larger mode velocity ratio and a tighter coupling characteristic than those of a general broadside-coupled CPW. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 156–160, 2000.

Finite ground plane effects on the radiation pattern of small microstrip arrays

The radiation characteristics of microstrip antennas consisting of two patch elements on small size substrates are studied by means of an approximate solution technique. Special attention is paid to the shielding effect due to finite ground plane diffraction. Experimental and theoretical results show that the back radiation is influenced by the sidelobe level and can further be reduced when the antenna is boxed. For a correct radiation pattern computation these diffraction effects need to be included in the design of small array as well as in that of single element antennas.

Analysis of one wide-band and high gain patch microstrip antenna using the FDTD method

We present results of a recent investigation into a wide-band and high gain patch microstrip antenna using the finite-difference time-domain (FDTD) method. The substrate–superstrate resonance technique was used to increase the antenna element gain. An aperture-coupled rectangular patch microstrip antenna with two superstrate layers was designed, and the effect of the finite ground plane on the gain of the antenna element was analyzed. The antenna was fabricated and tested. The measured results are presented in comparison with the simulated ones. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 468–473, 1999

Analysis of one wide‐band and high gain patch microstrip antenna using the FDTD method

We present results of a recent investigation into a wide-band and high gain patch microstrip antenna using the finite-difference time-domain (FDTD) method. The substrate–superstrate resonance technique was used to increase the antenna element gain. An aperture-coupled rectangular patch microstrip antenna with two superstrate layers was designed, and the effect of the finite ground plane on the gain of the antenna element was analyzed. The antenna was fabricated and tested. The measured results are presented in comparison with the simulated ones. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 468–473, 1999

Modelling of the coupling structure of a HTS DC SQUID amplifier

In order to estimate self- and mutual inductances of the input coil and the pick-up loop of a YBCO SQUID amplifier operating at 77 K, a simple method based on the determination of the current and flux distributions into the superconductors is presented. The cases of inductors (single loop and spiral) and induced circuits (closed and open loop) are considered. The authors stress the difference between a SQUID pick-up loop and a directly coupled magnetometer depending upon their action on the input inductance. Finally, the coupling efficiency and the ground plane effect are calculated and measured for various patterns.

Electromagnetic interference from carrier channels on finite-length power lines above a lossy ground in a wide frequency range

Prediction models of the electromagnetic interference generated by carrier channels on multiconductor power distribution lines with nonradiating terminal loads are presented. The proposed formulations are addressed to the evaluation of the radiated field components in a wide frequency-range, by including the effects of the lossy ground plane and removing the hypothesis of unidirectional current propagation. The validity of the infinite-length approximation and of the complex image approach are investigated, with reference to different line-configuration, in case of wire-to-ground and wire-to-wire signal transmission.

Control of microstrip antenna radiation characteristics by ground plane size and shape

The effects of various physical and electrical parameters of circular microstrip patch antennas on their radiation characteristics are investigated. These parameters include the ground plane size, substrate permittivity, ground plane and substrate thicknesses and the ground plane shape. The investigation is carried out for the first four modes. A numerical method based on the moment methods is utilised which computes surface currents on the conductors and field distributions on the dielectric substrate. To avoid excessive computation, circular patch and ground planes are selected to allow the use of moment method for bodies of revolution. Initially, a circular patch with a finite ground plane is studied. The ground plane is then deformed, above and below the substrate, to increase the gain or shape the radiation patterns. It is shown that the ground plane effects are significant and a wide range of radiation pattern shapes can be generated.

Fast-wave resonance by space-wave leaky mode carrying dominant-mode-like currents

By closely examining the resonant phenomena of a suspended, flat wire resonator, this paper speculates on the existence of the fast-wave mode causing the anomalous resonance that cannot possibly be explained by the well-known bound mode. This is followed by proposing a guiding structure model that allows the assessment of the effects of ground plane and sidewalls (external objects) on the guiding properties. The numerical accuracy of the full-wave spectral-domain approach method for the electrically large model is validated by performing the rigorous convergence study. A series of measurements on the resonator are conducted for the same guiding structure of various lengths, confirming that the anomalous resonance is indeed caused by a fast-wave in the form of a space-wave type leaky mode which also exhibits almost identical modal currents to those of the bound mode.

Radiated emissions and immunity of microstrip transmission lines: theory and reverberation chamber measurements

The increasing complexity of electronic systems has introduced an increased potential for electromagnetic interference (EMI) between electronic systems. We analyze the radiation from a microstrip transmission line and calculate the total radiated power by numerical integration. Reverberation chamber methods for measuring radiated emissions and immunity are reviewed and applied to three microstrip configurations. Measurements from 200 to 2000 MHz are compared with theory, and excellent agreement is obtained for two configurations that minimize feed cable and finite ground plane effects. Emissions measurements are found to be more accurate than immunity measurements because the impedance mismatch of the receiving antenna cancels when the ratio of the microstrip and reference radiated power measurements is taken. The use of two different receiving antenna locations for emissions measurements illustrates good field uniformity within the chamber.

Effects of a finite ground plane on the mutual coupling between rectangular microstrip antennas

Characteristics of the mutual coupling between rectangular microstrip antennas on a conducting ground plane of finite extent are experimentally investigated. The E- and H-plane mutual coupling coefficients of antennas on ground planes of various sizes are measured and analyzed. It is found that the finite extent of the ground plane has a greater effect on the E-plane coupling than on the H-plane coupling. © 1996 John Wiley & Sons, Inc.

Effect of a finite ground plane on radiated emissions from a circular loop antenna

A thin-wire circular loop antenna located above a perfectly conducting square plate is analyzed by a physical optics (PO) method. The electric field integral equation (EFIE) is solved using the method of moments to compute the current on the loop in the presence of an infinite ground plane whereby the edge effects of the plate on the loop current are neglected. The current distribution on the loop is obtained from a full-wave Fourier series analysis which requires no matrix inversion. We then use physical optics to compute the current induced on the plate in terms of the incident magnetic-field intensity. Our aim is to compare the PO solution with results obtained from a mixed wire-patch MOM code and explore its accuracy as a function of plate size and loop height. The benefits are considerable reduction in analytical and computational efforts and much less CPU time. >

Ground plane effects in monolithic millimeter-wave integrated circuits

The effect of a lossy ground plane on the propagation parameters of a monolithic millimeter-wave microstrip on a semiconductor substrate is studied. The full-wave spectral-domain technique, which can take into account the thickness and conductivity of the ground plane, is used. When considering an ideal ground plane, the losses are very low and quasi-independent of the thickness of the semiconductor. Taking into account the losses of the ground plane, it is shown that the propagation losses are not only dependent on the thickness of the ground plane but also on the thickness of the semiconductor. These losses increase significantly as this thickness is reduced. >

Transverse radiation pattern of a slotted waveguide array radiating between finite height baffles in terms of a spectrum of two-dimensional solutions

In arrays of waveguide fed slots, the periodicity of the slots causes grating lobes off the principal planes, referred to as second-order beams. To suppress these lobes, parallel plates baffles) on both sides of the array can be used. In this paper, a linear array of longitudinal slots radiating between such baffles of finite height is analysed. The three-dimensional (3D) field problem is reduced to a two-dimensional (2D) problem via a Fourier transform. An integral equation for the 2D problem is developed and solved. The 3D radiation pattern, including the effect of a finite ground plane outside the baffles, is calculated from the 2D solutions. Results for various baffle dimensions, showing the attenuation of second-order beams, are presented and computed solution has been verified by measurements.

Deflection of electron beams by ground planes

Analytic methods are used to determine the effect of a nearby ground plane on the trajectory of a relativistic electron beam passing through dense gas. The beam is shown to respond to the ground plane in one of two distinct modes, determined by beam current and energy. Low-power beams deflect from the ground plane and tear longitudinally. High-power beams do not deflect or tear but tilt, i.e., the beam axis is no longer parallel to the direction of propagation. This conclusion is reached by computing the net beam force as a superposition of the ‘‘bare’’ ground-plane forces, the shielding forces from the beam-generated plasma, the body coupling forces induced by beam tilt, and the force that arises as the beam separates from the plasma. Effects from electromagnetic retardation and ground resistivity are shown to be negligible in typical cases of interest, and the interaction between ground planes and other external forces is discussed as well.

Effects of ground plane and dielectric truncations on the efficiency of a printed structure

Effects of ground plane and/or dielectric truncation on the radiation efficiency of a printed radiator are studied. A closed-form expression for the reflection coefficient of surface wave modes from the truncated edge is obtained. Numerical results for the reflection coefficient and the radiation efficiency are discussed, and radiation patterns for various dielectric constants, substrate thicknesses, and ground plane dimensions are presented. It is found that for certain ground plane dimensions the radiation efficiency is considerably lower than normal; these dimensions should be avoided to reduce the surface wave loss. >

Effects of finite ground plane on the radiation characteristics of a circular patch antenna

An analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented. The induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of the patch. The radiated fields contributed by the induced current on the ground plane and the equivalent sources on the physical aperture yield the radiation pattern of the antenna. Radiation patterns of the circular patch with finite ground plane size are computed and compared with the experimental data, and the agreement is found to be good. The radiation pattern, directive gain and input impedance are found to vary widely with the ground plane size. >

An antenna pattern measurement technique for eliminating the fields scattered from the edges of a finite ground plane

A novel antenna pattern measurement technique is presented to eliminate the effects of the finite ground plane and anechoic chamber wall reflections which significantly perturb antenna pattern measurements. This technique consists of the measurement of the edge-diffracted fields and their subsequent subtraction from the original pattern. A simple theoretical model is developed to introduce the subtraction technique, and comparisons are made which show the excellent agreement between theoretical (assuming an infinite ground plane) and 'corrected' experimental antenna patterns. Experimental results are given for open-ended waveguide, microstrip patch, and monopole antennas mounted on circular and square ground planes of various sizes. Time gating techniques are illustrated as well.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The finite ground plane effect on the microstrip antenna radiation patterns

The uniform geometrical theory of diffraction (GTD) is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. The source field from the radiating patch is calculated by two different methods: the slot theory and the modal expansion theory. Many numerical and measured results are presented to demonstrate the accuracy of the calculations and the finite ground plane edge effect.

Effect of a ground surface on blast wave propagation

The effect of a complex ground plane on the waveform from a blast has been numerically simulated. This first approximation ignores all nonlinear effects associated with the finite amplitude of the wave. The input waveform taken from small charge explosion data is Fourier transformed; each of the Fourier components is propagated from the source to the receiver using the theory of Donato [J. Acoust. Soc. Am. 60, 34–39 (1976)]; the wave at the microphone is then reconstructed via on inverse transform. The reconstructed wave-form is strongly dependent on the range and assumed surface.

Effect of finite size of ground plane on the impedance of a monopole immersed in a lossy medium

The effect of finite size of the ground plane on the impedance of a monopole immersed in a lossy medium is studied. The theoretical results show that for water medium and for the ratio of the ground-plane radius to free-space wavelength equal to and greater than 0.2, the effect of ground plane on the monopole impedance is negligible.