Showing papers on "Microstrip published in 1976"

Linearly polarized microstrip antennas

Abstract: An equivalent network for square and rectangular shaped microstrip radiating elements is derived. In order to simplify the problem the radiating element is considered as two slots separated by a transmission line of low characteristic impedance. The slots are characterized by their radiation pattern, directivity, and equivalent admittance. A design procedure for open circuit halfwave resonators and for arrays of such resonators is given. Finally, some antennas in the X band are designed and measured.

Inverted Strip Dielectric Waveguide for Millimeter-Wave Integrated Circuits

Abstract: A new type of dielectric waveguide, which has a number of advantages over other previously available waveguide structures for millimeter-wave integrated circuits, is described. Dispersion characteristics and the field distributions in the waveguide are calculated using the concept of effective dielectric constant. Field distributions have been measured in the 80-GHz range in order to check the accuracy of the analytical results. This measurement has been done using a novel experimental technique, which should also be applicable to many other millimeter-wave waveguides and components.

The Design and Performance of Three-Line Microstrip Couplers

Abstract: An analysis is presented of microstrip-coupler circuits consisting of three parallel lines. The analysis is based on the existence of three mode impedances. Design equations describing the performance of this type of coupler are derived and allow the prediction of its matching and transmission properties. Numerical results using finite difference methods are presented for a three-line microstrip coupler made on an alumina substrate (k = 9.8). Experimental results for a 10-dB tbree-line coupler with a center frequency of 4 GHz show that its performance can be reasonably well predicted by the developed theory.

Slow-Wave Propagation Along Variable Schottky-Contact Microstrip Line

Abstract: Schottky-contact microstrip lines (SCML) are a special type of transmission line on the semiconducting substrate: the metallic-strip conductor is specially selected to form a rectifying metal-semiconductor transition while the ground plane exhibits an ohmic metallization. Thus the cross section of SCML is similar to that of a Schottky-barrier diode. The resulting voltage-dependent capacitance per unit length causes the nonlinear behavior of such lines. In this paper a detailed analysis of the, slow-wave propagation on SCML is presented, including the effect of metallic losses. Formulas for the propagation constant and characteristic impedance are derived and an equivalent circuit is presented. Conditions for slow-mode behavior are given, particularly taking into account the influence of imperfect conductors and defining the range of many interesting applications. Experimental results performed on Si-SCML are compared with theory.

A New Integrated Waveguide-Microstrip Transition (Short Papers)

Abstract: A new waveguide-microstrip transition is described. This design provides wide-band performance (18-26 GHz) and very good reproducibility without the need for variable elements. The circuit is fully integrated on the substrate and the characteristics are much less sensitive to small variations in the dimensions than other known transitions. A narrow-band version has been made for the telecommunication band in particular (17.7-19.7 GHz) with a VSWR less than 1.1 and an attenuation less than 0.25 dB. The design can easily be scaled to other frequencies and is especially useful at frequencies above 10 GHz.

Analysis of Microstrip-Like Transmission Lines by Nonuniform Discretization of Integral Equations

Abstract: The nonuniform discretization of the integral equation on the tangential electromagnetic (EM) field on the boundary surface is proposed as a numerically efficient method to analyze the microstrip-like transmission lines. The calculated results of the propagation constant of the microstrip line based on this method are compared with other published analytical results. Various types of planar striplines are treated by the same formulas. The dominant and higher order modes of shielded microstrip line are discussed and compared with the longitudinal-section electric (LSE) and linear synchronous motor (LSM) modes of a two-medium waveguide.

Dielectric Waveguide Microwave Integrated Circuits---An Overview

Abstract: An integrated circuit technique for microwave and millimeter wavelengths which uses refractive-type waveguides and signal processing coupled with planar integration techniques characteristic of microstrip microwave integrated circuits (MIC's) is described. Following a comparison of the optical and millimeter approaches to this circuit technique, a discussion of transmission lines and components for millimeter wavelengths is presented. System applications are also described.

2-18-GHz Dispersion Measurements on 10-100-Omega Microstrip Lines on Sapphire

Abstract: Dispersion measurements on microstrip lines with characteristic impedances between 10 and 100 Omega are described, covering the frequency range 2-18 GHz. Single-crystal sapphire cut with a specified crystal orientation was used as the substrate material. Microstrip effective permittivities were calculated from the resonant frequencies of open-ended straight resonators using a technique which eliminated end-effect. The experimental results are compared with some recent dispersion theories. An empirical dispersion formula is independently developed, and is shown to provide well-fitting curves for all the measured dispersion results.

Coplanar Lines : Application to Broadband Microwave Integrated Circuits

Abstract: The paper begins with a brief review of some of the shortcomings of the microwave microcircuit techniques most widely used in research and industry (e.g. microstrip, suspended stripline, and slot line). This is followed by a discussion of the advantages likely to be associated with the utilization of the coplanar line technique. The propagation characteristics are then determined using a digital calculation program. Finally, several applications are discussed involving or impedance matchers capable of operating at Ku-band frequencies.

A Microstrip and Stripline Crossover Structure (Letters)

Abstract: A microstrip or stripline four-port structure which allows two signal paths to physically cross over while maintaining high isolation is described in this letter.

Quasi-Static Characteristics of Microstrip on an Anisotropic Sapphire Substrate

Abstract: The well-defined and repeatable electrical properties of single-crystal sapphire make it an attractive substrate material for microstrip, but its dielectric anisotropy constitutes an important design complication. This paper describes investigations into the quasi-static characteristics of single microstrip lines on sapphire substrates cut with a specified orientation. To account for anisotropy, a new permittivity parameter epsilon/sub req/ is introduced, which is a function of the Iinewidth to substrate-height ratio W/h. The variation of epsilon/sub req/ with W/h is derived by finite-difference methods. Universal curves for microstrip on correctly orientated sapphire are presented, showing 1) epsilon/sub req/, 2) the low-frequency limit of effective microstrip permittivity epsilon/sub e0/, and 3) the characteristic impedance of the line Z/sub 0/, all as functions of W/h.

An analysis technique for microstrip antennas

Abstract: A method to analyze a microstrip antenna is presented. It involves representing the antenna by a fine wire grid immersed in a dielectric medium and then using Richmond's reaction formulation to evaluate the piecewise sinusoidal currents on the wire grid segments. The calculated results are then modified to account for the finite dielectric discontinuity. A comparison of calculated and measured results is presented. This technique will serve as an excellent tool to design microstrip antennas.

Accurate analytical determination of quasi-static microstrip line parameters

Abstract: In the design of microstrip components, the analytical equations of Wheeler have an advantage in handling-speed and simplicity over alternative quasi-static analyses involving complex computation by numerical methods. Wheeler equations can produce excessive errors, however, unless care is taken particularly in the choice of changeover point between equations for narrow or wide strips. This paper shows that for alumina-type substrates with 8 < er < 12, the Wheeler analysis and synthesis equations produce results within 1% of those given by selected numerical methods, when the changeover points are correctly chosen. Additional new and modified formulae are presented for the direct calculation of microstrip effective permittivity from either W/h or Z0, also to an absolute accuracy of less than 1%. These complete an accurate set of analytical equations for quasi-static analysis or synthesis of microstrip lines.

Electronically scanned microstrip antenna array

Abstract: A microstrip electronically scannable antenna is realized by means of an array of disc elements that are separated from a common ground plane by a dielectric medium. The center of each disc element is electronically short circuited to the ground plane. At least two pairs of diametrically opposed short circuitry switches (diodes) are connected between certain locations on the peripheral edge of each disc element and the ground plane. The polarization and phase of the reflected energy of each disc element is controlled by certain combinations of open circuited and short circuited pairs of short circuiting switches. Electronic scanning is achieved by control of the short circuitry switches, specifically by digitally controlling the forward and reverse bias of the diodes.

A New Impedance-Matched Wide-Band Balun and Magic Tee

Abstract: A new wide-band microwave balun particularly attractive for microstrip circuitry is described in which the normally balanced line is in the form of a pair of equal-amplitude and antiphase unbalanced lines. This novel method of input-output coupling allows a coplanar arrangement of input and output microstrip lines. Often the balanced and unbalanced line impedances in a balun are unequal, necessitating an impedance-matching network. A first-order reflection coefficient theory that mutually considers the impedance effects of the balun cavity, a compensating stub, and a quarter-wave transformer is used to design wide-band impedance-matched baluns. Curves of VSWR versus bandwidth are presented for several balanced-to-unbalanced line-impedance ratios. Experimental results are given for an octave-band impedance-matched balun with a balanced-to-unbalanced impedance ratio of 2:1. The new wide-band balun is adaptable to a microstrip magic tee. A proposed magic tee that relies on circuit symmetry for operation has multioctave bandwidth potential.

Curvature effect in microstrip ring resonators

Abstract: A planar waveguide model for microstrip is used to obtain an improved method of correcting for curvature effects in ring resonators. The extent of the improvement is illustrated by a comparison of experimental measurements and theoretical predictions of microstrip dispersion.

Broadband, microwave, two-stage, stagger-tuned, field effect transistor amplifier

Abstract: A microwave-integrated-circuit amplifier provides a broadband response in e region of 1-10 GHz. The amplifier includes: a microstrip which provides distributed circuit values for tuning; first and second microwave FETs included in the microstrip and tuned to the upper and lower cutoffs of the bandwidth, respectively; and a non-reciprocal microwave isolator which passes a signal in only one direction and is connected between the first and second microwave FETs.

Launcher and microstrip characterization

Abstract: A method for identifying scattering parameters of launchers and uniform microstrips is presented. It is shown that 8 complex measurements (magnitude and phase) on two microstrips which are different only in length, inserted between two launchers, can give, with suitable algebraic treatment, the S-parameters of either the microstrips and the launchers. This technique is promising for deembedding active devices as well for microstrip discontinuities.

Equivalent Circuit Parameters of Microstrip Step Change in Width and Cross Junctions (Short Papers)

Abstract: The inductive component of the equivalent circuit of microstrip step change in width and cross junctions has been evaluated theoretically and a comprehensive set of results is presented. Experimental results for one set of step changes in width obtained using the resonant method compare well with theory.

Coupled fed magnetic microstrip dipole antenna

Abstract: A coupled fed magnetic microstrip dipole antenna consisting of a thin eleically conducting, rectangular-shaped radiating element (resonator) and a nonradiating coupler formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The radiating element has one end shorted to the ground plane. There is only a single mode of oscillation. Oscillation takes place along the length of the radiating element, and the length determines the resonant frequency. The feed point is normally located at the end of the coupler; energy is in turn coupled to the radiating element. However, the feed point can be located along the uncoupled edge of the coupler. Input impedance matching is determined by a combination of the coupler length and the separation between the coupler and the radiating element, and also the feed location when fed along the uncoupled edge of the coupler.

Wide beam microstrip radiator

Abstract: A radio frequency antenna structure is disclosed wherein a raised pedestal portion of the ground plane surface is provided and above which pedestal portion a microstrip radiator is disposed. The microstrip radiator is thus disposed on a pedestal at a predetermined distance above the base ground plane to produce mirror image or apparent radiating aperture(s) therebelow. The combined radiation pattern from the real radiating aperture(s) and the mirrored image(s) thereof produces an increase in radiation power at low pointing angles located near the ground plane, thus producing a wider radiation beam without sacrificing radiation efficiency. This form of raised pedestal microstrip radiator is especially useful in phased arrays where it is desired to steer the beam of the array to angles near the ground plane itself.

Simple analysis of anisotropic microstrip lines by a transform method

Abstract: For the TEM-mode investigation of microstrip lines on anisotropic substrates, a simple, but rigorous, transformation is introduced, which converts the anisotropic electrostatic field into an isotropic one with similar shape; the latter has been extensively analysed in the past. The transformation also applies to related anisotropic problems. Results for single and coupled lines are presented. Dispersion is briefly commented on.

Predicted frequency dependence of microstrip characteristic impedance using the planar-waveguide model

Abstract: Modifications to the equation defining the width of the planar-waveguide model for microstrip are proposed, and which predict a frequency-dependent characteristic impedance in better agreement with the results of dynamic theories of microstrip.

Broadband high frequency mixer

Abstract: A broadband mixer has two separate tapered ground plane microstrip baluns associated with a first signal port and two separate tapered ground plane microstrip baluns associated with a second signal port together with a frequency converter or mixer portion coupled between the baluns associated with the first and second signal ports and a third signal port. The frequency converter or mixer portion is comprised of eight diodes in a double balanced bridge arrangement having two sets of terminals associated with the first and second signal ports, each of the terminals of said two sets being separated from each of the terminals of the third signal port by a diode to electrically isolate their respective signals. The baluns associated with the first and second signal ports provide for the transformation of unbalanced input signals to balanced signals at the frequency converting diodes. Another balun coupled between the diode bridge arrangement and the third signal port provides an unbalanced signal at the third signal port in response to balanced signals at the diodes from signal inputs at the first and second signal ports. The baluns associated with the first and second signal ports are cross-connected so that their respective signals do not pass through to the opposite signal port. The circuit is reversible in that a signal may be input to or output from any signal port.

Measurement of Guide Wavelength in Rectangular Dielectric Waveguide

Abstract: Oscillators in the microwave and millimeter-wave region were constructed wherein the resonators consisted of sections of rectangular dielectric waveguide. While adding thin blocks of dielectric to increase the mechanical length of the resonator, the power output and frequency were measured. Using this technique, the experimental value of the wavelength in the longitudinal direction, lambda/sub g/, was determined. These experimental data were then compared with calculations predicted by optical theory. Good agreement was found where the bulk wavelength was small compared with the cross-sectional dimensions of the dielectric. If the half-wavelength in the dielectric was comparable with the dielectric dimensions, the values of lambda/sub g/ were greater than the theoretical values. In the process of carrying out these experiments, a new type of oscillator is described which provides a power ontput comparable with diodes in metal-walled cavities. In addition, the new dielectric cavities are simple in construction and are compatible with dielectric waveguide, image line, or microstrip systems.

Microstrip Array Antenna

Abstract: An equivalent network for rectangular shaped microstrip radiating elements is derived. In order to simplify the problem the radiating elements are considered as two slots separated by a transmission line of low characteristic impedance. The slots are characterized by their equivalent admittances. The radiation conductance is derived and found to be proportional to the width for wide strips and to the square of the width for narrower strips. The equivalent susceptance, due to end effects, is represented by a capacitor. The narrow bandwidth of the microstrip radiating elements is due to the high impedance ratio between the slot and the strip. Finally, the network model is used to design a dual polarized planar array.

Notch fed twin electric micro-strip dipole antennas

Abstract: Twin electric microstrip dipole antennas consisting of thin electrically ducting rectangular shape elements formed on both sides of a dielectric substrate. In these antennas the element on one side of the substrate is the mirror image of the element on the other side of the substrate. Each of the elements act, in effect, as a ground plane for the other. The thickness of the substrate to a large extent determines the bandwidth of the antenna and the length of the conducting elements on both sides of the substrate determines the resonant frequency.

Computation of Propagation Constants for the Fundamental and Higher Order Modes in Microstrip (Short Papers)

Abstract: A method used to treat static problems in microstrip is extended to treat time-harmonic problems of covered and uncovered microstrip. Both longitudinal and transverse currents are taken into account, Impedance functions (integrals of Green's functions) for covered and uncovered microstrip are derived in terms of improper integrals (limits 0 --->/spl infin/). Accurate evaluation of these integrals is carried out. Matrix methods are then used to obtain propagation constants for the fundamental and higher order modes. Data obtained agree closely with experiment.