Showing papers on "Microstrip published in 1983"

Considerations for millimeter wave printed antennas

Abstract: Calculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies. Printed dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, and gallium arsenide substrates are considered. Data are given for resonant length, resonant resistance, bandwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Also presented is an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array. The data are calculated by a moment method solution.

Substrate Optimization for Integrated Circuit Antennas

Abstract: The reciprocity theorem and integral equation techniques are employed to determine the properties of integrated-circuit antennas. The effect of surface waves is considered for dipole and slot elements on substrates. The radiation and bandwidth of microstrip dipoles are optimized in terms of substrate thickness and permittivity.

Optimum Design of 3-Db Branch-Line Couplers Using Microstrip Lines

Abstract: A computer-aided design is described that makes it possible to reduce the internal impedance levels of branch-line couplers so that they may be physically constructed by microstrip lines, where the Fletcher-Powell search method has been used to optimize the design. Because microstrip lines are severely restricted in their usable impedance range, the 3-dB couplers presented here should be useful for numerous balanced-type components such as balanced mixers. The validity of the design has been experimentally verified in the microwave and millimeter-wave region.

Determination of Loaded, Unloaded, and External Quality Factors of a Dielectric Resonator Coupled to a Microstrip Line

Abstract: In the case of a dielectric resonator coupled to a microstrip line, the relations for the determination of unloaded, loaded, and external quality factors, in terms of directly measurable reflection or transmission coefficient at the resonant frequency, have been derived and represented on the corresponding vectorial and scalar planes. Construction of a linear frequency scale and a graphical method to accurately determine the unloaded Q from the loaded Q measurement presented.

Analytical and numerical techniques in the Green's function treatment of microstrip antennas and scatterers

Abstract: In the paper, the mode theory of wave propagation in stratified media is used to establish the spatial Green's functions associated with a microstrip structure. They correspond to the fields and potentials created by a horizontal electric dipole placed on the air/dielectric interface and are expressed as Sommerfeld integrals. Near- and far-field approximate analytical evaluations of these integrals are rigorously derived. They allow a quantitative discussion of the scope and limitations of the static microstrip theory, and point out the relevance of surface wave effects in microstrip. The most interesting situation when both source and observer are in the air/dielectric interface is studied extensively. Numerical methods to evaluate Sommerfeld integrals in such situations are reviewed, and several new accurate techniques are introduced and discussed in detail.

Microstrip reflect array for satellite communication and radar cross-section enhancement or reduction

Abstract: A passive array of resonantly-dimensioned microstrip antenna radiator patches are closely spaced (i.e., less than one-tenth wavelength) above a ground plane and individually associated with transmission line segments terminated so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along the transmission lines and are absorbed by the terminations or reflected therefrom. In the latter case, the reflected r.f. energy is re-transmitted in a predetermined direction as a re-directed r.f. electromagnetic field. The presently preferred embodiment is a relatively thin, flexible and thus conformable layered structure formed by selectively etching conductive material from one side of a metallically cladded dielectric sheet. For satellite communication, a flat reflectarray may be associated with a primary r.f. transmitter/receiver structure disposed at a focal area or spot of the reflectarray having an appropriately phased aperture (e.g., parabolic). For radar cross-section enhancement or reduction, the reflectarray aperture is phased so as to retro-reflect incident r.f. fields or so as to scatter, otherwise misdirect or absorb (e.g., by using lossy resistive transmission line terminations) the incident r.f. field.

Measurement and Computer-Aided Modeling of Microstrip Discontinuities by an Improved Resonator Method

Abstract: The broad-band characterization of microstrip discontinuities by an improved resonator technique is describecl This technique involves hitherto unknown expressions accounting for nonsymmetrical gap coupling and employs an efficient error function for the computer-aided modeling of microstrip n-ports It is applied to derive new analytical results for microstrip corners and chamfered right-angle bends

Considerations for Millimeter Wave Printed Antennas

Abstract: Absiruct4alculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would he the case for printed antennas at millimeter wave frequeneies. Prioted dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, abd gallium arsenide substrate are considered. Data are given for resonant length, resoriant resistance, bahdwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Ah presented is an optimizatidn procedure for maximizing or minimizing power launched into surface waves from a multielemerit printed antenna array. The data are calculated by a moment method solution.

Analysis of Slow-Wave Coplanar Waveguide for Monolithic Integrated Circuits

Abstract: The slow-wave characteristics of an MLS coplanar waveguide are analyzed using two different full-wave methods mode-matching and spectral-domain technique. The theoretical results obtained with them and the experimental values are in good agreement. Several important features of the MIS coplanar waveguide are presented along with some design criteria.

Rectangular microstrip patch antennas with infinite and finite ground plane dimensions

Abstract: The rectangular microstrip patch antenna has been extensively analyzed with regard to its input impedance and resonant frequency, both for infinite and finite ground plane dimensions. For infinite ground planes existing formulas have been compared and improved parameters presented. The influence from the side current radiation has been discussed as well. For finite ground plane dimensions the contribution from the ground plane edge diffraction has been accounted for in an equivalent radiation conductance and an equivalent diffraction susceptance. Formulas for these parameters have been developed on the basis of different theories. They are valid under the condition that only one of the ground plane dimensions are finite at the same time. Experimental investigations are carried out to test the accuracy of the developed formulas, showing good accuracy under the given conditions.

Measurement and Modeling of the Apparent Characteristic Impedance of Microstrip

Abstract: Voltage and current cannot be defined uniquely for microstrip except at zero frequency, and therefore microstrip has not been rigorously incorporated into circuit theory. However, in engineering practice, micro-strip exhibits an apparent characteristic impedance, denoted here by ZA, that can be measured. Three methods of measuring ZA were devised and used in measuring three impedance levels of microstrip. These methods are described and experimental results presented. The measurements of ZA were found to be consistent with the power-current characteristic impedance definition of the approximate longitudinal-section electric (LSE) model of nricrostrip. Simple approximate formulas for representing ZA are also discussed.

Coupling Coefficient Between Microstrip Line and Dielectric Resonator

Abstract: A formula of the coupling coefficient between a dielectric resonator and a microstrip line is derived from an analysis of the transmission characteristics of the microstrip line coupled to the dielectric resonator. A practical method of calculation is developed using Fourier analysis. The calculated values show good agreement with the experimental values.

Theoretical and experimental investigation of a microstrip radiator with multiple lumped linear loads

Abstract: A simple theory is developed for the analysis of microstrip patch elements which are loaded at one or more points with lumped linear load impedances. The analysis is based on a cavity model in which the shape of the field distribution between the patch and ground plane is assumed to be well approximated by that of the resonant modes of a corresponding magnetic- and electric-walled cavity. The resonant mode of the loaded cavity is represented as an appropriate superposition of the modes of the corresponding unloaded cavity. The characteristic equation for the resonant frequencies of the loaded cavity is obtained in terms of the load impedances and the unloaded cavity multiport open-circuit parameters. An analysis of the input impedance of a rectangular microstrip element shorted at an arbitrary point has been implemented and the results show good agreement with experiment. An ancilliary result showing the equivalence between a thin strip and a circular cylinder model of a feed current distribution...

Effect of substrate thickness on the performance of a circular-disk microstrip antenna

Abstract: The effect of substrate thickness on the characteristics of a circular-disk microstrip antenna is examined. In the literature this effect has been dealt with theoretically, but experimental results explicitly showing the effect of substrate thickness on resonant frequency, input impedance, and bandwidth do not seem to be readily available.

Mlcrostrip Reactive Circuit Elements

Abstract: Quantitative design information is given for some pIanar distributed microwave circuit elements. A microstripline section is calculated as a parallel tuning element, and the radial-line stub and open- and short-circuited coupled microstrip stubs are treated. Typical applications showing measurements on circuits utilizing planar tuning elements are also presented.

Analysis of microstrip wraparound antennas using dyadic Green's functions

Abstract: The radiation pattern of microstrip wraparound antennas was obtained here using a theory based on dyadic Green's functions for concentric-cylindrical layered media. The dielectric layer that is usually neglected as a first-order approximation was considered here. An asymptotic expression for the dyadic Green's function that takes into account only the space wave is first obtained. Radiation patterns for various radii, permittivities, and thicknesses of the dielectric layer of a microstrip wraparound antenna were obtained using as a source a uniform annular magnetic current obtained by means of a cavity model with conducting magnetic walls. The calculated values of the percent pattern coverage decreases as the thickness and the permittivity of the dielectric layer increase. The influence of the dielectric layer is more pronounced for radiation direction near that of the axis of the cylindrical surface. It is also shown that the radiation patterns at a frequency of 2.0 GHz are not much dependent on the diameter of the antenna for values from 3 to 120 in.

Radio frequency antenna with controllably variable dual orthogonal polarization

Abstract: A controllable dual input/output port power divider coupled with a controllable phase shifter feed a dual ported dual polarized microstrip antenna structure. By controlling the power divider and phase shifter, arbitrary orthogonal polarization (e.g., linear, circular or elliptical) radiated r.f. fields are obtained. Virtually the entire structure comprising the dual port power divider, phase shifter and microstrip radiator may be formed of shaped photo-chemically etched microstrip conductors disposed a very short distance (e.g., less than one-tenth wavelength) above a conductive reference surface.

Multilayered printed circuit board with controlled 100 ohm impedance

Abstract: A printed circuit board of six planar layers has the layers separated by a dielectric of epoxy glass. The two central layer planes form a ground plane and a voltage plane. The two external planes and the internal planes involve series of microstrip signal lines of specially calculated widths and dielectric separations to provide an essentially 100 ohm characteristic impedance for the signal lines in reference to the ground and voltage planes.

Integrated oscillator and microstrip antenna system

Abstract: A three-element active device is physically and electrically integrated (e.g., by soldering) onto shaped conductive areas in a thin conformable microstrip structure which includes a microstrip antenna radiator. Two of the elements of the active device are connected to microstrip reactance structures which form a series-resonant partial oscillator circuit. The third (output) element of the active device is connected directly to the microstrip antenna radiator via a microstrip transmission line which, together, directly provide the r.f. load impedance for the thus completed oscillator circuit. Quarter wavelength r.f. microstrip segments are also provided to facilitate the feeding of d.c. bias to the active device without disturbing the r.f. circuitry. The oscillator load impedance to be provided by the microstrip radiator is predetermined in accordance with conventional device-line or loadpull impedance measurements so as to maximize the power output of the active device.

Finite Element Analysis of Lossy Waveguides-Application to Microstrip Lines on Semiconductor Substrate

Abstract: The development of Maxwell's equations is made considering the electromagnetic fields as vector distributions. With the aid of the finite element method, an analysis of lossy shielded inhomogenous waveguides of arbitrary shape is described. To solve the complex matrix system an iterative procedure is presented. The method is applied to study the propagation on MIS or Schottky contact microstrip lines.

Spectral Domain Investigation of Surface Wave Excitation and Radiation by Microstrip Lines and Microstrip Disk Resonators

Abstract: Some considerations concerning the spectral domain computation of microstrip lines and disk resonators including surface wave excitation and radiation are performed. Numerical results are presented for some representative covered and open configurations and are discussed with respect to the effective physical mechanisms.

A geometrical theory for the resonant frequencies and Q -factors of some triangular microstrip patch antennas

Abstract: A geometrical theory of the resonant frequencies and radiation Q -factors of 45\deg-45\deg-90\deg, 60\deg-60\deg-60\deg , and 30\deg-60\deg-90\deg triangular microstrip patch antennas is developed, based upon the rereflection of rays making up the field underneath the patch. Extremely simple formulas for Q_{r} are obtained, which enables an extensive comparison of relative radiation Q for various patch shapes to be made. This theory replaces other much more cumbersome expressions from the literature, or gives new formulas for some cases for the first time.

A New Transmission Line Approach for Designing Spiral Microstrip Inductors for Microwave Integrated Circuits

Abstract: Spiral microstrip inductors with up to two full turns have been modeled by using parallel coupled and single transmission lines. With this method, the electrical characteristics of these inductors, which may be fabricated as elements of MIC and MMIC circuits, can be designed for reactance up to 200 ohms with a maximum error of 15 percent for frequencies up to the K/sub u/ band.

Method and apparatus for matched impedance feeding of microstrip-type radio frequency antenna structure

Abstract: The center region of a dual slot microstrip-type antenna radiator "patch" structure is forced to take on a controlled non-zero radio frequency impedance by the provision of a slot formed therein at the center region. By controlling the dimension of such an impedance-matching slot in the radiator patch, a feedpoint connection may be made at the center region of the radiator patch and still achieve matched impedance feed. Because the feedpoint can thus be centrally located within the antenna structure, any spurious radiation which occurs from the feedpoint connection or associated feedlines does not tend to skew the overall or composite radiation antenna of the pattern as much as when such feedpoints are asymmetrically disposed on the radiator patch with respect to the primary radiating apertures.

Mutual Impedance Computation Between Microstrip Antennas

Abstract: A moment-method solution for the mutual coupling between rectangular microstrip antennas is presented. The grounded dielectric slab is accounted for exactIy in the analysis.

Microstrip linear array with polarisation control

Abstract: A new configuration of microstrip series-fed linear array is presented; in which the choice of the specific array geometry permits selection of the dominant radiated polarisation from a wide range. The array consists of a series of right-angle bends in a microstrip line whose spacing determines the polarisation. Using an equivalent magnetic current analysis, closed-form expressions are derived for the geometry required for specific polarisations. Design limitations are noted and, in particular, the appearance of grating lobes in the radiation pattern in some cases indicates the use of high dielectric-constant substrates. Measured results for four arrays, having polarisations of current interest, verify the design technique for crosspolarisation levels down to - 25 dB and sidelobe levels down to - 20 dB. The performance limitations are critically assessed, and it is concluded that the new configuration will result in arrays having reduced bandwidth, or efficiency, with radiation-pattern control comparable to other microstrip arrays, combained with polarisation control which may well make them attractive in some system application.

A modular approach for the design of microstrip array antennas

Abstract: A method for the design of medium gain (15-25 dB) microstrip array antennas is described. A modular approach is utilized in which a given antenna is used as a building block for higher gain antennas. A series of X -band antennas were built in this way, and the results seem to validate the usefulness of the method.

Connector for joining microstrip transmission lines

Abstract: Two microstrip transmission line substrates are mounted face-to-face at a fixed separation determined by mating connector halves which provide microstrip to coaxial transmission line transitions. Each connector half includes a body portion, a stand-off portion and a coaxial connector portion.