Abstract: Microstrip antennas consist of a planar resonant radiating element parallel to, but separated, from a ground plane by a thin dielectric substrate ( t \ll \lambda ). These antennas are very thin and consequently rugged and easy to mount. They may be fed from the back through the ground plane or from the edge by depositing microstrip lines on the dielectric substrate. Several varieties of microstrip antennas are discussed in this paper. Design procedures are given for both linearly and circularly polarized antennas. Measured patterns are presented for antennas from UHF through C band.

Abstract: Although microstrip transmission lines have been widely used in microwave integrated circuits, the discontinuity structures in the microstrip transmission lines such as a gap, an abruptly ended strip conductor, and so on, have hardly been analyzed. An analytical method and numerical results for a gap capacitance in the microstrip transmission line are described. The equivalent circuit parameters are formulated with three-dimensional Green's functions, based on a variational principle. The numerical results are in good agreement with the published experimental data. The fringing effect of an abruptly ended strip conductor is also investigated.

Abstract: The integral equations that describe the charge distribution near an open-circuited microstrip end are formulated and subsequently solved by a projective method. The solution hinges on development of computationally efficient techniques for dealing with the singularities that occur by special quadrature formulas. The necessary formulas are described and tabulated. These techniques are then used to find open-circuit capacitance values for microstrip. It is found that the curves of excess capacitance versus width are easily describable by empirical equations; such equations are presented, along with the curves themselves. For strip widths between 0.1 and 10 times the substrate thickness and for dielectric constants in the range 1-51, the given data are believed accurate to within a few percent.

Abstract: Formulas and graphs are presented for the effective relative permeability and the filling factors of magnetic substrates in microstrip. Both the propagation and the magnetic loss filling factors are included. In the calculation of these quantities, use was made of the filling factors for dielectric substrates obtained from Wheeler's analysis and a duality relationship between magnetic and dielectric substrates derived in this paper.

Abstract: A method for calculating microstrip discontinuities and T junctions is described, and a waveguide model for the microstrip line is defined. With the help of this model and the use of an orthogonal series expansion, a solution of the above problems is found. Numerical results for the scattering matrices of both the discontinuities and the junctions are given.

Abstract: The matrix methods are applied to three-dimensional microstrip problems with emphasis upon the general problem of discontinuities in microstrip. Discontinuities considered are 1) open circuits, 2) change of width, and 3) gap in microstrip. Also, the capacitance of rectangular sections of microstrip is computed. Computed data agree well with experiment and data in the literature.

Abstract: By means of finite difference methods, dispersion curves are obtained for the fundamental and higher order hybrid modes in both single and coupled microstrip. Structures of realistic proportions are investigated by the use of a graded finite difference mesh. Variational methods are used in deriving the finite difference equations. The higher order modes are found to be similar to LSM slab line modes. A spurious nonphysical class of solutions is found to exist in this and similar formulations, the characteristics of which are described.

Abstract: Microstrip transmission lines used in microwave integrated circuits are dispersive. The dispersion of the lines is fully characterized by the frequency-dependent normalized phase velocity VP which is equal to the ratio of guide wavelength λ g to free-space wavelength λ 0 . An approximate equation is given for the normalized phase velocity VP and for the frequency-dependent line impedance Z for standard microstrip transmission lines. Comparison with available experimental data and computed data shows that the error of the approximation is less than 3 percent for microstrip transmission lines commonly used in engineering applications.

Abstract: Experimental data taken on microstrip built on ferrite and garnet substrates are presented and compared with theoretical values calculated from formulas derived in a previous paper which were extended to gyromagnetic media. Good agreement has been obtained between experiment and theory. In particular the observed increase in wave attenuation at frequencies near /spl omega//sub m/ is fully explained when the frequency dependence of the characteristic impedance is taken into account.

Abstract: Motion within a large specified volume is detected by multiple ultrasonic transducer assemblies with a redundant microwave antenna to reduce false alarms. Each of the ultrasonic transducer assemblies contains a plurality of highly directive transmitting radiating elements and/or a plurality of highly directive receiving elements. Combining networks interconnect the various radiating elements in parallel to a frequency source. The microwave transducer includes a transmit/receive antenna coupled to a microstrip oscillator through a microstrip balanced mixer. Signals from the ultrasonic transducers are processed by means of time integration to provide an alarm signal. Similarly, signals received at the microwave antenna are processed by means of time integration to provide an alarm signal. Alarm signals from both the ultrasonic subsystem and the microwave subsystem are combined in logic that responds to generate a system alarm only upon the simultaneous existence of alarm signals from both sources. Also coupled to the ultrasonic subsystem and the microwave subsystem is an automatic self-testing and tamper determining system. When either transducer source indicates a fault condition, an alarm signal is generated by combining logic networks.

Abstract: The design of octave-bandwidth microstrip interdigital dc blocks is presented. Data for a 7.75- to 16.3-GHz design are given and correlated with an approximate equivalent circuit based on even and odd mode propagation in coupled microstrip. Additional data are tabulated reflecting the ability to shift the frequency band of operation.

Abstract: Calculated data, which extend the previous results of Farrar and Adams, are presented for the microstrip end effect as a function of width and substrate permittivity. With a quasistatic approximation, the excess capacitance associated with the open end was determined utilising the method of moments. Good experimental agreement was observed.

Abstract: This paper describes two new integrated-circuit media called integrated fin-line and oversized microstrip. Their advantages over conventional microstrip at millimeter wavelengths include: reduced radiation, single-mode operation, less stringent tolerances, compatibility with hybrid devices, and ease of transition to standard waveguide.

Abstract: This short paper describes a method for computing the edge capacitance of finite or semi-infinite sections of microstrip transmission lines. The approach is based on Galerkin's method applied in the Fourier-transform domain. It is mathematically simple and requires the inversion of rather small-size matrices.

Abstract: Arrays wherein the radiator elements act also as shield conductors of feed lines arranged to provide cophasal interconnection of the radiators without physical transpositions, particularly adaptable to fabrication by etched circuit techniques, as microstrip on the surfaces of a single dielectric substrate.

Abstract: A microstrip bandpass filter has been built with dielectric resonators made of a temperature-compensated material. Its unloaded Q at X band is calculated to be greater than 1200, a four-fold improvement upon conventional printed-on devices. With additional temperature compensation, a temperature coefficient less than 5 ppm/°C is shown to be feasible.

Abstract: Formulas derived by mode summation give the six B- and H-field components in the various air and dielectric regions of a slot-line cross section. These formulas are valid except when very close to the slot, where approximations in the analysis cause a large error. A quasi-static method yields a second set of formulas that apply near the slot. Thus the field is determined satisfactorily in all parts of the cross section. Graphs of the H components show that elliptical polarization exists, with the best approach to circularity near the slot and near the opposite surface of the substrate. Quantitative field data are useful for analysis and design of slot-line components, such as ferrite devices, dielectric-resonator filters, directional couplers, and broad-band transitions to coaxial line or microstrip.

Abstract: The well-known integral-equation formulation of the microstrip problem is solved by a projective method using trial functions that preserve the essential singularity in charge distribution at the strip edges, Suitable computer programs are presented. This formulation is believed particularly useful in the analysis of strip discontinuities, where details of the charge distribution cannot easily be traded off against speed of computation.

Abstract: By determining up to 16 GHz the effective dielectric constant for microstrip lines with various strip widths, it has been found that anisotropy in alumina substrates considerably affects the wavelength and is responsible for most of the discrepancy between theory and experiments,

Abstract: An electronically variable delay line including a wafer of silicon on one side of which a thin insulating layer is deposited. A highly conducting ground plane contacts the silicon wafer on its remaining side while a highly conducting microstrip line contacts the insulating layer. The microstrip line contacts the silicon wafer through small holes etched in the insulating layer at predetermined intervals. At these holes, P-N junctions are formed. The P-N junctions are reverse biased so as to vary the effective thickness of the insulating layer to vary the delay time by creating a depletion layer within the silicon wafer which acts as an effective insulator.

Abstract: A low-cost microstrip 50-/spl Omega/ termination is described having a maximum VSWR of 1.46 (including the mismatch contributed by a microstrip launcher) from 1 to 18 GHz. It consists of a thin-film chip resistor with a matching structure. Experimental resistor characterization, equivalent-circuit modeling, and matching considerations are presented.

Abstract: The bandwidth characteristic of a microstrip N-pole M-throw switch is improved by providing the spacing, which is between a printed pole conductor and a printed throw conductor thereof and across which is connected a PIN diode to the two conductors, with a predetermined spacing relationship W 0.215 lambda /3, where lambda is the wavelength at the upper frequency of the bandwidth range of the switch. Further improvement of the bandwidth characteristic is provided by utilizing the inductances of bare wire conductors as chokes or as the inductive component of low pass LC filters that are used in the biasing of the switches.

Abstract: Introduction of lumped elements in the microstrip itself proved to be a rather simple way to overcome the difficulties encountered by achieving tight coupling (3 dB) and high directivity ( > 20 dB) for proximity couplers on plain microstrip. Three couplers were made as proof; two 3 dB proximity couplers: a distributed-lumped and an octave-flat lumped one, and a 8.34 dB decade-wide asymmetric coupler of the DuHamel & Armstrong type. It is evident that application of the new technique is not restricted to couplers.

Abstract: The properties of MIS (metal-insulator-semiconductor) or Schottky barrier microstrip transmission-line structures are shown to permit the realization of a wide variety of signal-processing devices including electronically variable delay lines and phase shifters, and parametric frequency converters and amplifiers.

Abstract: A frequency-selective directional coupler is provided which comprises a fast-wave transmission line placed in proximity to a slow-wave transmission line. The fast wave line can be a waveguide, strip-line, or microstrip line which follows a fairly direct path between two points. The slow wave line can be a helix or a meander line.

Abstract: A microwave structure comprising a parallel transmission line that is bisected by a conducting septum to form two independent microstrip circuits that are in anti-phase; i.e., the conducting septum becomes a common ground plane for a pair of equal amplitude microstrip circuits that are in anti-phase relative to the common ground at points equidistant from the point of bisection of the parallel transmission line. In one embodiment, the proprosed microwave structure is utilized as a power divider with input power being supplied to a conventional microstrip circuit formed of a pair of spaced parallel conductor strip members which also form the parallel transmission line and the anti-phase microstrip circuits, and whose widths are varied to form a reflectionless transition from the input microstrip circuit to the parallel transmission line and subsequently to the pair of output microstrip circuits, each of which receives half of the input power supplied to the device.

Abstract: An approach to the solution of the equivalent electrical length, and the additional capacitance, associated with a right-angled bend in microstrip line are outlined. The calculations were performed under static assumptions, corresponding to a quasi-TEM mode of propagation of the fields. Although little theoretical work existed for comparison at the time of writing, encouraging reinforcement was gained with experimental results cited from the literature.

Abstract: Measurements have been made of the even- and odd-mode guide wavelengths of coupled microstrip lines on alumina between 1 and 12 GHz. Both modes show a linear relationship of negative slope between normalised wavelength and frequency.

Abstract: A microwave-integrated-circuit phase shifter comprising a dielectric substrate such as ferrite, one side being metallized to form a slot line and the other being metallized to form a parallelling microstrip transmission line, the two lines being coupled together through the dielectric substrate. A region of circular polarization of the input signal is set up between the lines and a magnetic field which is adjustable in amplitude is applied in the direction of the two lines. Variation of the amplitude of the magnetic field varies the amount of phase shift between the input and output of the device.