Showing papers on "Microstrip published in 1986"

A reciprocity method of analysis for printed slot and slot-coupled microstrip antennas

Abstract: A method is presented for the analysis of slot-type discontinuities in microstripline. The approach is based on the reciprocity theorem and uses the exact Green's functions for the grounded dielectric slab in a moment method solution for the unknown antenna currents. The method is applied to two specific geometries: a radiating slot in the ground plane of a microstripline, and an aperture coupled microstrip patch antenna. Results for antenna impedance are compared with measurements, and far-zone patterns are calculated. The method is shown to be quite versatile, and should find application to related problems.

Analysis of an aperture coupled microstrip antenna

Abstract: A microstrip patch antenna that is coupled to a microstripline by an aperture in the intervening ground plane is analyzed. Coupled integral equations are formulated by using the Green's functions for grounded dielectric slabs so that the analysis includes all coupling effects and the radiation and surface wave effects of both substrates. A Galerkin moment method solution of the coupled integral equations agrees quite well with measured data. Design data are contained in parameter studies, many of which are verified by experimental results.

An experimental investigation of electrically thick rectangular microstrip antennas

Abstract: The electromagnetic properties of electrically thick rectangular microstrip antennas were investigated experimentally. Antennas were fabricated with different patch sizes and with electrical thicknesses ranging from 0.03 to 0.23 wavelengths in the dielectric substrate. The resonant frequencies were measured and compared to existing formulas. The bandwidth was calculated as a function of electrical thickness and the antenna radiation patterns were measured.

Considerations in the Use of Coplanar Waveguide for Millimeter-Wave Integrated Circuits

Abstract: Using a full-wave analysis, coplanar waveguide (CPW) transmission line is compared to microstrip in terms of conductor loss, dispersion, and radiation into parasitic modes. It is shown that, on a standard 0.1-mm semiconductor at 60 GHz, the dimensions of CPW can be chosen to give better results in terms of conductor loss and dispersion than microstrip. A calculation of parasitic mode generation is presented for CPW on a semiconductor for an open substrate, for a substrate suspended above a ground plane, and for substrates separated from a ground plane by quartz.

A new model for broadband waveguide to microstrip transition design

Abstract: A new model is presented which permits the prediction of the resonant frequencies created by antipodal finline waveguide to microstrip transitions. The transition is modeled as a tapered transmission line in series with an infinite set of coupled resonant circuits. The resonant circuits are modeled as simple microwave resonant cavities of which the resonant frequencies are easily determined. The model is developed and the resonant frequencies determined for several different transitions. Experimental results are given to confirm the models.

The Finite-Difference-Time-Domain Method and its Application to Eigenvalue Problems

Abstract: This paper describes the application of the finite-difference method in the time domain to the solution of three-dimensional (3-D) eigenvalue problems. Maxwell's equations are discretized in space and time, and steady-state solutions are then obtained via Fourier transform. While achieving the same accuracy and versatility as the TLM method, the finite-difference-time-domain (FD-TD) method requires less than half the CPU time and memory under identical simulation conditions. Other advantages over the TLM method include the absence of dielectric boundary errors in the treatment of 3-D inhomogeneous planar structures, such as microstrip. Some numerical results, including dispersion curves of a microstrip on anisotropic substrate, are presented.

Dispersion of Picosecond Pulses in Coplanar Transmission Lines

Abstract: The dispersion of coplanar-type transmission lines has been extended to the terahertz regime to examine the distortion of picosecond electrical pulses. Dispersion of coplanar waveguides is compared to equivalent microstrip lines. Agreement with available experimental data is demonstrated for coplanar strips, An approximate dispersion formula for coplanar waveguides is also reported for CAD applications.

Different formulations for numerical solution of single or multibodies of revolution with mixed boundary conditions

Abstract: A numerical method for determining the electromagnetic field in the presence of one or several bodies of revolution is presented. The objects can be made of conductors, dielectrics or their combinations. The excitation is assumed to be due to a plane wave or infinitesimal electric dipoles located within or outside the dielectric. Several formulation types are considered and used to investigate the scattering by different objects. It is found that for moderate values of the dielectric constant, all formulation types give satisfactory results. However, for small or large relative permittivities the solution accuracies depend on the formulation type. As an application of the method to practical problems, two special cases of dielectric rod and microstrip antennas are considered. These antennas have widespread applications and the proposed method can be used to investigate their performance accurately.

Finite phased arrays of rectangular microstrip patches

Abstract: Finite phased arrays of rectangular microstrip patch antennas are analyzed. Reflection coefficient magnitudes, element patterns and efficiency (based on power lost to surface waves) are calculated for various sized arrays on substrates of practical interest and are compared with previous infinite array solutions. Measured element patterns and mutual coupling data for a small array are presented and compared with calculations.

The Nature of the Leakage from Higher Modes on Microstrip Line

Abstract: Some confusion in the literature is clarified regarding the properties of microstrip line higher modes in the neighborhood of cutoff. It is shown that those modes become leaky in that range, and that the leakage occurs in two forms, a surface wave and a space wave. Numerical values obtained from an accurate analysis are presented that illustrate the nature of the leakage for microstrip lines with either open or covered tops.

Microstrip leaky wave strip antennas

Abstract: During the late 1870's. a paper presented by H. Ermert at the European Microwave Conference stimulated instant controversy. The paper was devoted to the properties of higher modes on microstrip line, and one of its conclusions was that a "radiation" region exists close to the cutoff of those modes. Because the description of this region, made in that talk and in published papers [1,2], was incomplete and therefore unclear to many, confusion persisted and certaln practical consequences remained hidden. Also in this general perlod. a paper by W. Menzel [3] presented a new traveling-wave antenna on microstrip line fed in its first higher mode and operated near t~ the cutoff of that mode. Menzel proposed his structure as a competitor to a microstrip patch antenna, and he therefore made his antenna short in terms of wavelength. He also assumed that the propagation wavenumber of the flrst higher mode was real in the very region where Ermert said no such solutions exist; since his guided wave, with a real wavenumber, was f a s t in that frequency range, Menzel presumed that i t should radiate. His approximate analysis and his physical reasoning were therefore also incomplete, but his proposed antenna was valid and his measurements demonstrated reasonably successful performance. The present paper flrst explains that the "radiation" region of Ermert is directly related to leaky modes, and that such a representation for this region is both convergent and practical. It then shows that Menzel's antenna Ls in reality a leaky wave antenna that was made too short: an accurate analysis of it not only explatns quantitatively the performance features of the antenna, but also indicates how they can be improved. Numerical values are presented to show what performance characteristics can be expected when leaky wave antennas of this class are properly designed.

Varactor Tuned Bandpass Filters Using Microstrip-Line Ring Resonators

Abstract: This paper describes the fundamental characteristics and experimental results of newly developed tunable bandpass filters using rnicrostrip-line ring resonators. The experimental filter has a steeper attenuation slope and less circuit instability than conventional filters, and it seems to be a suitable filter for MICs or MMICs.

Quasi-TEM Analysis of Microwave Transmission Lines by the Finite-Element Method

Abstract: This paper describes a finite-element approach to the quasi-TEM analysis of several different types of isolated and coupled microwave transmission lines. Both the first- and higher order ordinary elements, as well as singular and infinite elements, are used to solve for the potential and field distributions in the cross section of the line. Next, the cross-sectional field distribution is inserted in a variational expression to compute the capacitance per unit length of the line, and the effective permittivity and characteristic impedance of the line are obtained from the capacitance value. A perturbational approach is developed for estimating the losses due to conductor and dielectric dissipation and computing the attenuation constant. Both the upper and lower bounds for the capacitance and the characteristic impedance are found by solving the original and the corresponding dual problem. Lines treatable by this method may contain an arbitrary number of arbitrarily shaped conductors, including a system of conductors placed either above a single ground plane or between two parallel ground planes, and inhomogeneous dielectric regions that can be approximated Iocally by a number of homogeneous subregions. The results obtained using the finite-element procedure have been compared for various types of microwave transmission lines and have been found to agree well with available theoretical and measured data.

Microstrip fed printed dipole with an integral balun

Abstract: A microstrip fed printed dipole with an integral balun is disclosed, fabricated upon a planar dielectric substrate by patterning metallizations disposed on the two surfaces of the substrate. In the arrangement, the ground plane of the unbalanced microstrip transmission line is bifurcated by a central slot to form a balanced transmission line coextensive with the slot which becomes a part of the arms of the dipole and which at the same time serves as the ground plane of a continuation of the microstrip feed. A continuation of the strip conductor of the unbalanced microstrip feed having a "J" shaped configuration continues over the bifurcated ground planes and crosses the slot in proximity to the dipole for effecting an efficient unbalanced feed to the balanced dipole. The arrangement has a double tuned characteristic with two available and independent adjustments facilitating reproducable, optimized broadband performance.

Application of the Boundary-Element Method to Waveguide Discontinuities (Short Paper)

Abstract: A numerical method for the solution of scattering of the H-and E-plane waveguide junctions is described. The approach is a combination of the boundary-element method and the analytical method. A general computer programs has been developed using the quadratic elements (higher order boundary elements). To show the validity and usefulness of this formulation, computed results are given for a right-angle corner bend, a T-junction, an inductive strip-planar circuit mounted in a waveguide, a waveguide-type dielectric filter, and an inhomogeneous waveguide junction, and a linear taper. Comparison of the present results with the results of the finite-element method shows good agreement.

The effect of various parameters of circular microstrip antennas on their radiation efficiency and the mode excitation

Abstract: The numerical solution of circular microstrip antenna is carried out using the method of moment. The effect of the probe position, The dielectric permittivity of the substrate, and the substrate thickness on the radiation pattern and the mode excitation efficiency are studied. It is found that the probe position and the patch size can be used to control the mode excitation efficiency, and heigher order modes can be generated using only one feed location. Also, the finite ground plane can be used to improve the symmetry of the radiation patterns. The technique is general and can be used to investigate other scattering and antenna problems involving axisymmetric geometries.

Comparison of Quasi-Static and Exact Electromagnetic Fields from a Horizontal Electric Dipole Above a Lossy Dielectric Backed by an Imperfect Ground Plane

Abstract: In most microstrip transmission lines, analysis is made assuming that a quasi-TEM mode exists and propagates down the line. The primary objective of this paper is to obtain the region of validity of this assumption. The second objective of this paper is to derive the expressions for the fields for a horizontal electric dipole over a Iossy dielectric medium backed by an imperfect ground plane. It is shown that, to a first approximation, fields at the air-dielectric interface are independent of the ground plane conductivity. Since we are interested in coupfing between lines, our interest is in the computation of the fields primarily at the air-dielectric interface. Finally, numerical results are presented to show where the quasi-static approximations deviate from the exact solution for a given microstrip geometry as the frequency of operation or the observation point is changed.

Generalized Scattering Matrix Method for Analysis of Cascaded and Offset Microstrip Step Discontinuities

Abstract: Detailed algorithms are presented for characterizations of cascaded microstrip step discontinuities, symmetric stubs, and offset step. The analysis is based on the generalized scattering matrix techniques after the equivalent waveguide model is introduced for the microstrip line.

The Microstrip Step Discontinuity: A Revised Description

Abstract: A systematic variety of frequency-dependent numerical results hitherto unavailable are presented for the shielded microstrip impedance step. The computational method used is a rigorous full-wave spectral-domain approach developed by Jansen. The given data describe the steps for two very common groups of dielectric substrates as a function of stepwidth ratio in the range of normalized frequencies where it behaves like a two-port. They represent new MIC design information and are compared with quasi-static results and the widely used magnetic-wall waveguide approximation. Beyond this, they are validated against the sparse step-discontinuity data available from previous rigorous approaches.

Surface mountable microwave ic package

Abstract: @ A surface mountable microwave IC package uses printed transmission lines on a printed circuit board in lieu of plumbing between milled packages. A backside co-planar waveguide is connected to a topside microstrip line by a through-hole in a carrier substrate. To compensate for inductance added by the hole and transmission line ends, a gap is adjusted to provide compensation capacitance. Hermeticity is assured by brazing a lead frame over the through-hole and using a solder sealed lid. The lid provides both hermeticity and shielding.

Waveguide-microstrip line converter

Abstract: A waveguide-microstrip line converter for mode conversion in transmitting signals from a waveguide to a microstrip line or in the reverse, which comprises a dielectric body, a probe formed integrally with and within the dielectric body, and a conductive layer formed over the surface of the dielectric body excluding a surface to be brought into contact with a waveguide and an area surrounding the connecting part of the probe. The conductive layer is formed over the entire surface of the dielectric body, and then part of the conductive layer is removed by etching to provide the uncoated surface to be brought into contact with the waveguide and the probe. Thus the probe is continuous with the conductive layer and is an integral part of the dielectric body, so that the performance of the probe is unaffected by vibration and the high frequency resistance across the short-circuit waveguide is reduced to reduce signal transmission loss.

Waveguide to stripline transition assembly

Abstract: The transition between a rectangular waveguide and a stripline is accomplished with an assembly which contains: a waveguide flange, a waveguide section, and a tapered wedge. The waveguide flange physically connects with the rectangular waveguide and the waveguide section. The waveguide section has the tapered wedge housed within it along its top, and is electrically connected to the ground planes of the stripline. The tapered wedge is electrically connected with the center conductor of the stripline, to provide a transition between the rectangular waveguide and the stripline. Optimum impedance matching and voltage standing wave ratio can be empirically determined in the assembly by inputting signals into the stripline or waveguide, and taking impedance measurements while moving a reflecting panel which rests behind the tapered wedge to different positions in the slotted waveguide section.

Dispersion of Transient Signals in Microstrip Transmission Lines

Abstract: The distortion of an electrical pulse caused by dispersion as it propagates along a microstrip line is investigated. A model for dispersion of the phase constant is selected to meet the frequency, accnracy, and microstrip parametric requirements. Numerical integration and Taylor series expansion approximation techniques are used to compute the shape of dc dispersed pulses having square and Gaussian envelope shapes. Taylor series expansion methods are more convenient for the analysis of RF pulses.

Dual band slotted microstrip antenna

Abstract: A dual band microstrip antenna including a slotted microstrip radiating pllel to and spaced from a ground plane with dielectric material therebetween, the slotted microstrip radiating and having a first resonance corresponding to the dominant radiation mode that would occur in an unslotted microstrip and a second resonance created by the slot. The polarizations of the two resonances are perpendicular to each other with the slot resonance being polarized along the centerline of the slot.

Accurate Solutions of Elliptical and Cylindrical Striplines and Microstrip Lines

Abstract: By the transformation methods, elliptical and cylindrical striplines and microstrip lines are theoretically analyzed. Rigorous derivations lead to the exact expressions of the characteristic impedance in closed-form. Elliptical microstrip lines are explored for the first time. For practical applications, elliptical and cylindrical striplines with finite thickness are also analyzed.

Input impedance of a probe-fed circular microstrip antenna with thick substrate

Abstract: A method of computing the input impedance for the probe fed circular microstrip antenna with thick dielectric substrate is presented. Utilizing the framework of the cavity model, the fields under the microstrip patch are expanded in a set of modes satisfying the boundary conditions on the eccentrically located probe, as well as on the cavity magnetic wall. A mode-matching technique is used to solve for the electric field at the junction between the cavity and the coaxial feed cable. The reflection coefficient of the transverse electromagnetic (TEM) mode incident in the coaxial cable is determined, from which the input impedance of the antenna is computed. Measured data are presented to verify the theoretical calculations. Results of the computation of various losses for the circular printed antenna as a function of substrate thickness are also included.

Analysis of planar strip geometries in a substrate-superstrate configuration

Abstract: A moment method procedure is used to analyze the behavior of several different configurations consisting of planar strips in a substrate-superstrate geometry. These include the microstrip transmission line, center-fed dipole, the mutual impedance between two dipoles, and the transmission-line coupled dipole. In each case some of the basic superstrate effects are discussed.

Coupling device between a metal wave guide, a dielectric wave guide and a semiconductor component and a mixer using this coupling device

Abstract: The invention provides a coupling device between a metal wave guide (three dimensional system) and an electronic signal processing circuit (two dimensional system). The transition is provided by means of a dielectric wave guide introduced longitudinally into the metal wave guide. A chamfer cut in the dielectric guide concentrates the energy of the input signal on a face of the dielectric bar, at the interface with another dielectric material (isolated image guide). At this interface, a microstrip line transmits the energy to a semiconductor component.

Analysis of arbitrarily shaped microstrip patch antennas using segmentation technique and cavity model

Abstract: Arbitrarily shaped microstrip patch antennas have been analyzed for resonant frequency, input impedance, and radiation patterns. The segmentation technique and the cavity model have been used for this purpose. The usefulness and the accuracy of the method are shown through comparison with experimental results for a rectangular ring antenna. The agreement is seen to be very good. Ihe method appears to be more efficient compared to those reported so far for arbitrary shapes. Moreover, feed reactance is built into the analysis. The method presented here can also be used to analyze microstrip antennas with various types of loadings, e.g., shorting pins, matched loads, etc.

Finite-Element Analysis of Slow-Wave Schottky Contact Printed Lines

Abstract: Extensive finite-element analyses on MMIC slow-wave structures with both Iocalized and layered models are presented Good agreement is achieved between the data presented here and other theoretical results and experiments Higher order elements that improve accuracy are discussed The comparative studies for Schottky contact microstrip and coplanar waveguide with Iocalized and layered models are presented Potential applications of the Iocalized models to more general and practical slow-wave circuits are also discussed