Showing papers on "Microstrip published in 1975"

Equations for Microstrip Circuit Design

Abstract: A method for determining the accuracy of computed impedance and wavelength data for microstrip is proposed. It is shown that the standard equations of Wheeler and Schneider have rather large errors. Revised equations for microstrip impedance and wavelength are given both for analysis and synthesis with accuracy better than 1%. A simple, accurate equation for the microstrip open circuit is presented. Experimental data on microstrip T-junctions are compared with existing theories. A new accurate equation is given for the reference plane displacement in the stub arm. Corrections are proposed in the existing equations for the other parameters of the equivalent circuit.

Microstrip Excitation of Magnetostatic Surface Waves: Theory and Experiment

Abstract: A model is developed for excitation of magnetostatic surface waves (MSSW) with microstrip transmission lines. Energy carried away in MSSW propagating perpendicular to the microstrip is related to electromagnetic (EM) energy propagating along the microstrip line by an equivalent radiation resistance. Supporting experimental results are in excellent agreement with predictions derived from this model.

Planar waveguide model for calculating microstrip components

Abstract: A planar waveguide model with a frequency-dependent effective relative permittivity and a frequency-dependent effective width is developed for the open microstrip line. The validity of this waveguide model is shown by experimental results from measurements with a resonator and a sliding-load technique.

The Design of Coupled Microstrip Lines

Abstract: Although graphical results and formulas are available for the design of microstrip couplers, the design procedure is hampered because even- and odd-mode impedances are always expressed in terms of the physical geometry. In practice the designer obtains these impedances and then requires to know the geometry given by them. A new design procedure for coupled parallel microstrip lines is therefore presented. The technique enables the geometry of the coupled lines to be obtained directly from the required even- and odd-mode impedances and uses single microstrip-line geometry as an intermediate step. The results are presented in graphical form using only two universal families of curves. Results are also presented in the form of simple formulas for design programs and also comparisons with practical results are made.

Calculation of Microstrip Discontinuity Inductances

Abstract: Inductive components of microstrip discontinuity equivalent circuits are calculated by the Galerkin method. The formulation and method of calculation are discussed and a large number of numerical results for symmetric corners, T junctions, and steps changes are presented. These results compare well with experiment.

The Equivalent Circuit of Some Microstrip Discontinuities

Abstract: The experimental characterization of some microstrip structures of common interest, including symmetrical T junctions, is described. Some results are compared with data derived from recent three-dimensiotial static theory and from the uniform plane-wave model. It is concluded that while the three-dimensional theory requires further improvement, it is generally in much better agreement with the measured data than the two-dimensional uniform plane-wave model.

Loss Considerations for Microstrip Resonators (Short Papers)

Abstract: The influence of radiation losses on the Q of microstrip resonators is shown for a variety of frequencies, characteristic impedances, substrate materials, and thicknesses. Radiation becomes a dominant factor at higher frequencies, especially for low-impedance lines and thick substrates with a low dielectric constant.

Microwave properties of nonlinear MIS and Schottky-barrier microstrip

Abstract: It is shown that metal-insulatior-semiconductor (MIS) and Schottky-barrier microstrip structures having substrate resistivities within a certain range propagate slow waves with phase velocities that are dependent upon the instantaneous voltage at each point along the line. This and other useful properties of these microstrips can be used advantageously in a number of microwave devices. Loss measurements for the MIS microstrip structure confirm the predictred frequency dependence of the attenuation constant. While the levels of measured attenuation presently achieved are fairly high (4.5 dB/cm at 1 GHz), several methods for reducing the attenuation are proposed. A number of devices are discussed, including an electronically variable phase shifter for which attenuation and phase-shift measurements are presented.

Three-Dimensional Transmission-Line Matrix Computer Analysis of Microstrip Resonators

Abstract: A wide range of microwave resonators are analyzed using the same three-dimensional transmission-line-matrix (TLM) computer program. The paper demonstrates the ease of application, versatility, and accuracy of the TLM method. The results presented include the dispersion characteristics of microstrip on dielectric and magnetic substrates and an example of a microstrip discontinuity. The surface-mode phenomenon of microstrip is also investigated.

Spectral-Domain Calculation of Microstrip Characteristic Impedance

Abstract: This paper presents a hybrid-mode solution for the characteristic impedance of microstrip on Iossless dielectric substrate. A solution to the hybrid-mode equations is obtained by applying the method of moments in the Fourier transform domain. Numerical results are presented showing the frequency dependence of both wavelength and characteristic impedance for single and coupled strips. These results are compared with those of other investigators in the low-frequency range.

Microstrip/stripline impedance transformer

Abstract: To eliminate reflections and oscillations when a low impedance level circuit is to be connected to a high impedance level circuit on a printed circuit board, a microstrip/stripline impedance transformer is inserted in between. This transformer is passive and bi-directional, i.e., it can be step-up or step-down. It is made of a continuous folded microstrip (also called a surface etched line) or a continuous folded stripline (also called a buried etched line) wherein each folded section is run in parallel with its preceding one. Because of the mutual coupling between each section with its preceding one, the line impedance of each section will be step-up or step-down depending on the impedance levels at both ends of the interconnection.

Nondestructive Measurement of Complex Permittivity for Dielectric Slabs (Short Papers)

Abstract: A method has been developed for the precise nondestructive measurement of the dielectric constant and losses of slab-like samples such as microstrip substrates, for instance Basically, the test setup consists of an open-ended rectangular waveguide, the flange of which is placed in contact with one side of the dielectric material, the other one being backed by a metal plate The waveguide can be either simply cut at its end, or terminated by an inductive or capacitive iris The reflection characteristics or the resonance parameters are related to the real and imaginary parts of the permittivity by means of computer-generated charts or an optimization program

Microstrip antenna structure

Abstract: A microstrip antenna radiator is disclosed which includes three edges spaced around its periphery defining three corresponding active slot areas wherein each slot has a different respectively corresponding resonant dimension associated therewith along a direction substantially transverse to the edge which defines the radiating slot. At least two dimensions of an essentially equilateral triangular shape are altered so as to provide the three different resonant dimensions for the radiator. Typically, at least two sides of such a triangular structure are altered such as by the formation of tab extensions or, alternatively, at least two apices of the basic triangular structure are truncated so as to produce different resonant dimensions in the radiator. Various combinations and permutations of such shape alterations may also be employed. Such a triangular microstrip radiator is especially adapted for elliptical or circular polarization and for utilization in arrays of such polarized elements wherein the triangular shape of each element permits a more nearly optimum spacing of the individual elements within one or more arrays.

Dual frequency microstrip antenna structure

Abstract: A conformal microstrip antenna structure formed by a plurality of separated spaced-apart electrically conducting elements on a dielectric substrate overlying a ground plane. The innermost edges of the separated conducting elements define two sets of two intersecting radiators which are fed by microstrip transmission circuits disposed within the space between the separated conducting elements to individually feed the various radiators and/or segments thereof from the common feed point. The dimensions of the conducting elements also determine the resonant frequency of the radiators and their relative phases such that dual frequency operation as well as circular and/or elliptical polarization of the received/transmitted electromagnetic radiation can be conveniently achieved.

Evaluation of the Equivalent Circuit Parameters of Microstrip Discontiuuities through Perturbation of a Resonant Ring (Short Papers)

Abstract: A resonant technique for evaluating the equivalent circuit of reciprocal microstrip discontinuities is described. The complex Z parameters of a discontinuity are related to the change in resonant frequencies and Q factors of a microstrip ring it perturbs. As an example, measurements made on inductive posts are presented and compared with theoretical values.

Millimeter waveguide to microstrip transition

Abstract: A waveguide to microstrip transition apparatus in which a waveguide coupledo a microstrip circuit is provided with a mode filter for suppressing spurious modes of electromagnetic signal propagation. The mode filter is attached to the end of the waveguide that is coupled to the microstrip circuit and the mode filter extends over a portion of the microstrip circuit.

Measurement of the effective relative permittivities of microstrip

Abstract: A new method for determining the effective relative permittivity of microstrip, even at high frequencies, is presented. Four microstrips having the same physical and geometric characteristics, but different lengths, are needed; the mismatch due to the launchers is completely overcome.

Analysis of lossy microwave structures and microstrip resonators by the TLM method

Abstract: Many problems in electrical engineering are associated with the way in which electric and magnetic fields propagate and distribute themselves in various media. Maxwell's equations provide a concise description for the interaction of fields with themselves and with the various boundaries of a problem. Therefore, a numerical procedure for the solution of these equations is an important consideration. This thesis shows how a general three-dimensional medium may be represented by an interconnection of continuous ideal two-wire transmission-lines made up of generalised two-dimensional nodes which are introduced in the earlier chapters. It is then shown how this model may be used for the numerical solution of the electric and magnetic vector fields within the medium. This is the TLM method of numerical analysis. A universal three-dimensional computer program based on the method is also introduced. This program has been written in only 110 lines of FORTRAN including the subroutines. The ease of application, versatility and accuracy of the TLM method is demonstrated by analysing a wide variety of microwave resonators using this program. The surface mode phenomenon of microstrip is also investigated.

Heat spreader and low parasitic transistor mounting

Abstract: An apparatus for heat spreading and low parasitic transistor mounting in high power microstrip circuit applications An electrically and thermally conductive strip is conductively affixed to the ground plane of a substrate containing the circuit The strip is shaped to fit substantially within a slot in a circuit carrier block (heat sink) such that the strip makes intimate contact between the mounting surface of the transistor mounted in the slot and the carrier block The strip provides the electrical connection between the ground plane of the substrate and the carrier block in addition to increasing the surface area for more efficient heat transfer, and thus, allows for the ground plane of the substrate to be attached to the block either by a non-metallic adhesive or by solder

Microwave Integrated Circuits

Abstract: Microwave integrated circuits , Microwave integrated circuits , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

New Design Techniques for Microstrip Antenna Arrays

Abstract: The radiation resistance of an open-circuit microstrip termination is to a good approximation, a simple function of the strip width thus suggesting a straightforward yet effective means of element control when used in a large array; furthermore the array bandwidth can be controlled to some extent. The design of linear and two dimensional resonant arrays based on this design procedure is formulated and examples at X and J band are outlined; the beamwidths and sidelobe levels are of the order ± 4.5° and -16dB respectively. The extension of the new technique to travelling wave arrays, circular polarisation and various substrates is under investigation and will be mentioned; computational aspects throughout will be discussed.

Co-planar lead connections to microstrip switching devices

Abstract: A method and apparatus are disclosed for providing co-planar connections to the terminal leads of a switching device from circuit elements located on opposite sides of a planar microstrip substrate. A through hole is provided in the substrate where the switching device is to be mounted. A conductive terminal is inserted through the hole. The terminal includes a portion contacting the circuit element on one side of the substrate and a portion extending through the hole to become substantially co-planar with the circuit elements on the opposite side of the substrate. A switching device is positioned in the hole to permit its leads to be connected to the extended portion of the terminal and to the microstrip circuit elements on the opposite side of the substrate.

Microstrip Varactor-Tuned Millimeter-Wave IMPATT Diode Oscillators

Abstract: Varactor-tuned millimeter-wave IMPATT diode oscillators in microstrip form using chip-mounted diodes are described. A nearly level output power of 28 /spl plusmn/ 8 mW was achieved over a 6-GHz tuning range. Tunable bandwidths as high as 8 GHz with 6-26 mW of power were obtained from a single source. P-type epitaxial silicon IMPATT diodes were used for both the active device and the tuning varactor functions.

Microstrip to waveguide adapter

Abstract: A method for permitting the use of "drop-in" waveguide structures in micrrip applications comprising the steps of: inserting a heavily loaded waveguide that is compatible in size to the stripline into a longitudinal hole cut in the stripline to accommodate the waveguide so that these two components are end-to-end; Attaching the ground plane of the stripline directly to one of the broad-walls of the waveguide; and Impedance matching the top, narrow conductor of the stripline to the waveguide completely external to said waveguide and attaching it to the remaining waveguide broad-wall.

Microwave heating apparatus with improved multiple couplers and solid state power source

Abstract: A cut-off tubular housing has flat surfaces for mounting multiple solid state microwave oscillators using microstrip circuitry, each exciting a wire-like resonant coupler wound on a central dielectric support tube for receiving a frankfurter or other material body. The couplers are longitudinally spaced and angularly staggered so that energy coupled to different regions of the body is absorbed by the material to thereby isolate couplers and hence sources even at close spacings. In a rectangular configuration, a non-resonant box has a planar array of serpentine or spiral resonant couplers with adjacent couplers oriented orthogonally to minimize coupling.

High Directivity Microstrip Couplers Using Dielectric Overlays

Abstract: Coupled-line directional couplers in microstrip suffer from low directivity due to the inequality of the even and odd mode wave velocities. A dielectric overlay improves the directivity, but it also tightens the coupling and depresses the coupler impedance. Design curves are presented for making velocity-compensated 50 ohm couplers taking the changes in coupling and impedance into account.

Frequency-dependent behaviour of microstrip offset junctions

Abstract: The scattering coefficients of a general microstrip offset junction are calculated. This is done by a modal analysis based on a microstrip-line waveguide model. Theoretical results are compared with measurement.

Miniaturized millimeter wave instantaneous frequency discriminator

Abstract: A microstrip instantaneous frequency discriminator operable at frequenciesbove 18GHz. A first power divider divides the input signal into equal power outputs which are used as the inputs to second and third power dividers. One of the outputs from each of the second and third power dividers is used as the input to a 180° hybrid and the other output from each of the second and third power dividers is used as the inputs to a 90° hybrid. The outputs of the 90° hybrid and the 180° hybrid are subsequently processed to provide signals suitable for a visual polar display of the instantaneous frequency and power level of the input signal.