Showing papers on "Microstrip published in 1978"

Planar Triangular Resonators with Magnetic Walls

Abstract: This paper gives the field patterns in triangular planar resonators having no variation of the fields along the substrate thickness. The TM fields in such resonators with magnetic boundary conditions are obtained by duality from the TE modes with electric boundaries. The theoretical description includes the cutoff numbers of the first few modes. The radiation Q factor of fundamental microstrip resonators of this type was found experimentally to be higher than that associated with conventional disk resonators. The performance of a microstrip circulator using a triangular resonator is also described.

A theoretical investigation of the rectangular microstrip antenna element

Abstract: A theoretical treatment of the rectangular microstrip radiating element has been performed. The element has been modeled as a line resonator with radiation taking place at the open-circuited ends. This has been verified by using a liquid crystal visual detector. With the simplified model, the input impedance and the far fields have been calculated for different resonant modes. The interaction between the radiating ends will effect the input impedance, and this has been considered by defining a mutual conductance. Also, a mutual conductance between microstrip elements has been expressed in far-field quantities and plotted as a function of spacing along the E - and H - planes. The directivity of an isolated element has been calculated as the directivity of one radiating end times the contribution due to the array factor.

Experimental Study of Symmetric Microstrip Bends and Their Compensation

Abstract: An experimental study of microstrip bends is described. For right-angle corners, equivalent circuit parameters covering a wide range of frequencies, linewidths, and permittivities are presented and compared with the limited theoretical values available. The influence of mitering or rounding of the corner was investigated, and useful empirical expressions are given for the optimum miter.

A Simple Method for Determining the Green's Function for a Large Class of MIC Lines Having Multilayered Dielectric Structures

Abstract: To find the characteristic parameters of the wave propagation in microstrip structures, several Green's function methods have already been developed, corresponding to particular geometric configurations In this paper, three of these methods are synthesized, showing that the final equations in the different cases are identical Moreover, using the transverse transmission line theory, the Green's function is solved numerically for an N-layer dielectric structure

High-Speed Computation of Single and Coupled Microstrip Parameters Including Dispersion, High-Order Modes, Loss and Finite Strip Thickness

Abstract: Based on an optimized rigorous hybrid mode solution for covered/open zero thickness microstrip patterns the following frequency dependent single and coupled line data are evaluated with very short CP-times: The characteristic impedances of the even and odd quasi-TEM modes, the propagation/attenuation constants and associated strip current density components of these and the higher order modes, the loss of the dominant modes under consideration of nonuniform strip current, substrate surface roughness and dielectric loss tangent. Finite strip thickness is introduced by a correction of the strip width input values.

A Generalized Spectral Domain Analysis for Coupled Suspended Microstriplines with Tuning Septums

Abstract: An efficient computation method is developed for solving the microstrip-type structures in which a number of conducting strips are located on several interfaces of dielectric layers. The method is applied to the coupled suspended microstripline with tuning septums on the underside of the suspending dielectric layer. The numerical solutions obtained by the new method are compared with available data. The method is believed useful in the design of tightly coupled structures such as the 3-dB hybrid as well as of transitions between different transmission lines for microwave and millimeter-wave integrated circuit application.

Interdigitated Microstrip Coupler Design

Abstract: A design procedure for four-line interdigitated couplers is presented which provides excellent agreement between performance and actual coupler dimensions. The inclusion of a correction term for the finite metal thickness of the microstriplines is significant. Using existing odd-and-even mode impedance data of only two coupled lines in the array actual coupling coefficients in the 2.5-6.5-dB range are predictable to within /spl plusmn/0.05 dB. Graphs are shown which relate fabrication tolerances of dielectric constant and physicaf fine dimensions to deviations in coupling and characteristic coupler impedance. The design was verified on 3-, 5-, and 6-dB couplers in the 1-5-GHz frequency range.

MIC Overlay Coupler Design Using Spectral Domain Techniques

Abstract: A quasi-TEM analysis of dielectric overlay microstrip is described for an overlay extending several conductor Iinewidths beyond the coupled lines. This method permits the analysis of numerous variations of overlay coupler geometries. The relevant spectral domain Green's function is given and used to generate a set of design curves when the overlay is identical in thickness and dielectric constant to the main substrate. A trial 8.34-dB coupler was built. Significant improvement in isolation was noted with the overlay when compared to the equivalently designed uncompensated coupler. The measured values of isolation agree very well with predicted values.

Generalized Spectral Domain Method for Multiconductor Printed Lines and its Application to Turnable Suspended Microstrips

Abstract: An efficient method is developed for obtaining propagation characteristics of microstripline type structures in which a number of conductors are located on various interfaces. Specific computations have been carried out for suspended microstripline structures with tuning conductive septums. A number of data useful for design are included.

Conformal microstrip phased array for aircraft tests with ATS-6

Abstract: The development of a novel L -band microstrip phased array for aircraft is described. The array is electronically steerable in elevation, conformal to the surface of an aircraft, 0.14-in thick, low cost in production quantities, installed without cutting large holes in the aircraft, and capable of 12-dB gain relative to right hand circular isotrope. The microstrip radiating element is described, and its operation is explained. The array design is considered in relation to ground plane curvature, grating lobes, sidelobes, beam shape and gain. A technique for obtaining 30\deg phase resolution from 3-bit phase shifters is presented. The design of simple loaded line and switched line phase shifters is reported.

Spurious radiation from microstrip

Abstract: The method of an earlier paper is applied to calculate the disturbances due to a number of discontinuities encountered in typical antenna feed and network structures, such as impedance changes, power dividers, T-junctions, open and short circuits etc., and these are compared for relative radiation. Error estimates due to some secondary effects are calculated and shown to be generally negligible. The process of radiation from an open circuit is studied in detail and it is shown that, although most of the radiation comes from the tip, a substantial amount is radiated and also absorbed to. about a free-space wavelength behind the discontinuity. A method analogous to the induced e.m.f. method is formulated and shown to confirm existing results for radiated power. A distinction is made between the phase centre for radiation, which is usually located at a discontinuity, and the source region for radiation. The two are not coincident and the latter may be quite extensive for microstrip radiations. The results are applied to show how the disturbances can affect the performance of a comb antenna and how they can also be utilised to enhance the efficiency of a strip-end radiator on a thin substrate.

Impedance of a circular-disc printed-circuit antenna

Abstract: The driving-point impedance of a printed-circuit antenna consisting of a circular disc separated by a dielectric from a ground plane is investigated experimentally. The impedance is measured as a function of the operating frequency for various disc diameters, thicknesses and permittivities of the dielectric and feed point positions. In addition, a theoretical parallel RLC circuit model is proposed and compared with the experimental data.

A Simple Method for Computing the Resonant Frequencies of Microstrip Ring Resonators

Abstract: A simple and efficient method for the computation of the resonant frequencies of microstrip ring resonators is presented. By means of the "reaction concept" a stationary formula for the resonant frequency of these resonators is derived. In this context a suitable approximation for the current distribution on the strip pertaining to the dominant mode has been made. The numerical results are in excellent agreement with experimental data corroborating the accuracy of the presented method.

Generalized Spectral Domain Method for Multi-Conductor Printed Lines and its Application to Tunable Suspended Microstrips

Abstract: An efficient method is developed for obtaining propagation characteristics of microstrip-line type structures in which a number of conductors are located on various interfaces Specific computations have been carried out for suspended microstrip line structures with tuning conductive septums A number of are included

Quarter wave microstrip directional coupler having improved directivity

Abstract: An improvement in directivity and isolation of a quarter wave microstrip directional coupler is achieved with the addition of a single capacitor placed across the directive port of the coupler.

Stripline patch antenna

Abstract: A conformal antenna having a microstrip patch centered below a slot in a undplane and covered by a dielectric window and coupled to a stripline feed.

Broadband microstrip antenna with automatically progressively shortened resonant dimensions with respect to increasing frequency of operation

Abstract: Variable impedance devices (e.g., series resonant circuits and/or transmission line tuning stubs) are connected to predetermined locations on a microstrip radiator patch for changing the effective resonant dimensions of the antenna as a function of frequency and thereby permitting operation over a broad range of frequencies.

A Better Microstrip Connector

Abstract: A microstrip connector has been developed which has a VSWR /spl ap/1.07 up to 18 GHz. Such low reflections allow very precision measurements to be made when characterizing microstrip components and circuit elements. Consequently this improvement in measurement resolution results in better design control and fewer design iterations. This performance has been achieved by incorporating a unique design which matches the electrical field patterns at the interface. Although a 7mm coax to 25 mil substrate design is shown here, the technique is applicable to other configurations and has been so applied.

Microstrip antenna structure having stacked microstrip elements

Abstract: The structure includes a ground plane and at least two stacked microstrip elements with each microstrip element comprising a conducting plane and a layer of dielectric material. The conducting planes and the intermediate dielectric layers are configured so that they resonate at closely spaced frequencies. Each conducting plane in the structure, except the top one, includes an opening which is large enough to permit sufficient electric field coupling to occur between the microstrip elements so that the individual response characteristics of the conducting planes merge to form a broadband response characteristic. The antenna of the present invention thus has a substantially improved bandwidth over prior art microstrip antennas.

Corner fed electric microstrip dipole antenna

Abstract: A corner fed electric microstrip dipole antenna consisting of a thin eleccally conducting, rectangular shaped radiating element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The feed point is located at one corner of the antenna element and the input impedance is matched with a matching microstrip transmission feed line connected to the corner of the antenna. The length of the radiating element is greater than the width and determines the resonant frequency along the Y axis (i.e., length dimension) and the width determines the resonant frequency along the Z axis (i.e., width dimension). This antenna is capable of generating linear polarized radiation along the length thereof with minimal cross-polarization when the radiating element width dimension approaches one-quarter waveguide wavelength and less using a single corner fed element and single feed point. Elliptical polarization is also available with the rectangular radiating element.

Calculation of Microstrip Bends and Y-Junctions with Arbitrary Angle

Abstract: A method is described for calculating the frequency-dependent scattering parameters of microstrip bends and Y-junctions with arbitrary angles. Use is made of a waveguide model and an orthogonal series expansion for the fields around the discontinuity of the bend, so that the excitation and propagation of higher order modes can be considered. The transmission properties of the Y-junctions are derived from those of the bends by a symmetry consideration. Numerical results are given for two different substrates and are compared with experimental data. Neglecting radiation effects, they are in good agreement.

Complex Radiation Impedance of Microstrip-Excited Magnetostatic-Interface Waves

Abstract: A technique is described for computing the radiation reactance of microstrip-excited MSSW's from a Hilbert transform of a previously derived expression of the radiation resistance. The series combination of the radiation reactance, radiation resistance, and an inductive reactance corresponding to a shorted section of microstrip line forms an equivalent circuit characterizing the excitation process. Supporting impedance measurements are presented and limitations of the model are discussed.

Simplified Design of Lange Coupler

Abstract: An approximate procedure is described for the computation of characteristic impedances and relative dielectric constants of the odd and even modes on the interdigitated microstrip coupler consisting of N conductors. The procedure requires the knowledge of 1) parameters of the two-conductor coupled microstrip and 2) parameters of the single microstrip.

Some Considerations About the Frequency Dependence of the Characteristic Impedance of Uniform Microstrips

Abstract: Various possible definitions of characteristic impedance are derived from two different microstrip models obtaining similar results. It is shown that slightly different definitions yield strongly different behavior versus frequency.

The Frequency Behavior of Stripline Circulator Junctions

Abstract: The frequency dependence of the circulation equations for Y-junction stripline and microstrip circulators is investigated, and a new set of design curves is generated for the frequency-independent forms of the circulation condition's roots for both below- and above-resonance cases. Using this new set of curves, the wide-band design predicted by Wu and Rosenbaum and Bosma's narrow-band design are analyzed and compared. Quantitative arguments for the effect of the junction parameters on the bandwidth are given. To support the arguments, the theoretical junction performance of the 7-15 GHz "continuous tracking" circulator reported by Wu and Rosenbaum is calculated and compared with the theoretical performance of a 24 GHz circulator junction designed using the same method. Experimental results also are presented for the 24 GHz design. An analysis for the effect of the ferrite thickness on impedance matching is also included.

Channel Dropping Filter for Millimeter-Wave Integrated Circuits

Abstract: The dielectric waveguide structure finds various applications in integrated circuits for the millimeter-optical-frequency range. Many passive and active devices, using dielectric waveguide, have been developed. From the viewpoint of Iow-loss property, the dielectric rectangular waveguide seems to be more suitable for integrated circuits. This paper describes the design method and experimental results for channel dropping filter using dielectric rectangular waveguide. Some experimental investigations of the dielectric rectangular waveguide properties are also presented. The channel dropping loss of the filter is 1.5 dB at a channel center frequency of 52 GHz with a 180-MHz 3-dB bandwidth. Experimental results agree fairly well with the theoretical calculations.

Analysis of the Microstrip and the Electrooptic Light Modulator

Abstract: Green's function for examples with an isotropic media is obtained using the image-coefficient method. The method is based on the boundary conditions and the reciprocity relation. Using this Green's function and solving directly the charge distribution on the strip, the line capacitances per unit length of a microstrip and of an electrooptic light modulator are obtained. High accuracy of this method is demonstrated by comparing the present results with the results obtained using the conformal mapping and with other data appeared in the literature. The charge distributions are also illustrated. Of particular interest is the effective filling fraction of the dielectric material, which depends mainly on the shape ratio and only slightly on the relative dielectric constant. The effective filling fractions are tabulated for the microstrip with a homogeneous dielectric substrate.

Multiconductor Couplers

Abstract: Analysis of electromagnetic fields of interdigitated couplers and derivation of propagation parameters such as the line impedances and wavelengths for even and odd modes resulted in designs of couplers with an arbitrary number of strips. Calculations were carried out on two-, three-, four-, and six-strip couplers and showed that results for two- and four-strip couplers were consistent with available published data. The three-strip coupler, which was designed and fabricated, achieved 3-dB coupling with a simpler configuration than Lange's interdigitated coupler and with characteristics consistent with calculated data. Coupling as tight as 1.5 dB was achieved by a six-strip coupler which was designed with a part of the ground plane of the microstrip substrate removed. This coupler can be used as the middle part of a three-section coupler for which test data shows a wide range of balanced coupling, from 2.5 to 12 GHz, with a coupling unbalance of less than /spl plusmn/0.6 dB. It was concluded from the calculation that couplers with more than six strips would not be very practical.