Showing papers on "Microstrip antenna published in 1986"

A reciprocity method of analysis for printed slot and slot-coupled microstrip antennas

Abstract: A method is presented for the analysis of slot-type discontinuities in microstripline. The approach is based on the reciprocity theorem and uses the exact Green's functions for the grounded dielectric slab in a moment method solution for the unknown antenna currents. The method is applied to two specific geometries: a radiating slot in the ground plane of a microstripline, and an aperture coupled microstrip patch antenna. Results for antenna impedance are compared with measurements, and far-zone patterns are calculated. The method is shown to be quite versatile, and should find application to related problems.

The Handbook of Antenna Design

Abstract: These books present the fundamental background, theory and analytical techniques of antenna design, dealing with a very wide range of antenna types from very low frequencies to millimeter waves.

Analysis of an aperture coupled microstrip antenna

Abstract: A microstrip patch antenna that is coupled to a microstripline by an aperture in the intervening ground plane is analyzed. Coupled integral equations are formulated by using the Green's functions for grounded dielectric slabs so that the analysis includes all coupling effects and the radiation and surface wave effects of both substrates. A Galerkin moment method solution of the coupled integral equations agrees quite well with measured data. Design data are contained in parameter studies, many of which are verified by experimental results.

An experimental investigation of electrically thick rectangular microstrip antennas

Abstract: The electromagnetic properties of electrically thick rectangular microstrip antennas were investigated experimentally. Antennas were fabricated with different patch sizes and with electrical thicknesses ranging from 0.03 to 0.23 wavelengths in the dielectric substrate. The resonant frequencies were measured and compared to existing formulas. The bandwidth was calculated as a function of electrical thickness and the antenna radiation patterns were measured.

Different formulations for numerical solution of single or multibodies of revolution with mixed boundary conditions

Abstract: A numerical method for determining the electromagnetic field in the presence of one or several bodies of revolution is presented. The objects can be made of conductors, dielectrics or their combinations. The excitation is assumed to be due to a plane wave or infinitesimal electric dipoles located within or outside the dielectric. Several formulation types are considered and used to investigate the scattering by different objects. It is found that for moderate values of the dielectric constant, all formulation types give satisfactory results. However, for small or large relative permittivities the solution accuracies depend on the formulation type. As an application of the method to practical problems, two special cases of dielectric rod and microstrip antennas are considered. These antennas have widespread applications and the proposed method can be used to investigate their performance accurately.

Finite phased arrays of rectangular microstrip patches

Abstract: Finite phased arrays of rectangular microstrip patch antennas are analyzed. Reflection coefficient magnitudes, element patterns and efficiency (based on power lost to surface waves) are calculated for various sized arrays on substrates of practical interest and are compared with previous infinite array solutions. Measured element patterns and mutual coupling data for a small array are presented and compared with calculations.

The Nature of the Leakage from Higher Modes on Microstrip Line

Abstract: Some confusion in the literature is clarified regarding the properties of microstrip line higher modes in the neighborhood of cutoff. It is shown that those modes become leaky in that range, and that the leakage occurs in two forms, a surface wave and a space wave. Numerical values obtained from an accurate analysis are presented that illustrate the nature of the leakage for microstrip lines with either open or covered tops.

Microstrip leaky wave strip antennas

Abstract: During the late 1870's. a paper presented by H. Ermert at the European Microwave Conference stimulated instant controversy. The paper was devoted to the properties of higher modes on microstrip line, and one of its conclusions was that a "radiation" region exists close to the cutoff of those modes. Because the description of this region, made in that talk and in published papers [1,2], was incomplete and therefore unclear to many, confusion persisted and certaln practical consequences remained hidden. Also in this general perlod. a paper by W. Menzel [3] presented a new traveling-wave antenna on microstrip line fed in its first higher mode and operated near t~ the cutoff of that mode. Menzel proposed his structure as a competitor to a microstrip patch antenna, and he therefore made his antenna short in terms of wavelength. He also assumed that the propagation wavenumber of the flrst higher mode was real in the very region where Ermert said no such solutions exist; since his guided wave, with a real wavenumber, was f a s t in that frequency range, Menzel presumed that i t should radiate. His approximate analysis and his physical reasoning were therefore also incomplete, but his proposed antenna was valid and his measurements demonstrated reasonably successful performance. The present paper flrst explains that the "radiation" region of Ermert is directly related to leaky modes, and that such a representation for this region is both convergent and practical. It then shows that Menzel's antenna Ls in reality a leaky wave antenna that was made too short: an accurate analysis of it not only explatns quantitatively the performance features of the antenna, but also indicates how they can be improved. Numerical values are presented to show what performance characteristics can be expected when leaky wave antennas of this class are properly designed.

The effect of various parameters of circular microstrip antennas on their radiation efficiency and the mode excitation

Abstract: The numerical solution of circular microstrip antenna is carried out using the method of moment. The effect of the probe position, The dielectric permittivity of the substrate, and the substrate thickness on the radiation pattern and the mode excitation efficiency are studied. It is found that the probe position and the patch size can be used to control the mode excitation efficiency, and heigher order modes can be generated using only one feed location. Also, the finite ground plane can be used to improve the symmetry of the radiation patterns. The technique is general and can be used to investigate other scattering and antenna problems involving axisymmetric geometries.

Silicon High Resistivity Substrate Millimeter-Wave Technology

Abstract: The application of molecular beam epitaxy (MBE) and X-ray lithography for the fabrication of monolithic integrated millimeter-wave devices on high-resistivity silicon has been investigated. Process compatibility and the retention of high-resistivity characteristics were measured using the spreading resistance method and Hall measurements after various process steps. Microstrip resonators of ring and linear geometry were fabricated ou 10 000 Omega · cm silicon substrates. For linear microstrip resonators, the attenuation was found to be less than 0.6 dB/cm at 90 GHz. A 95-GHz IMPATT oscillator circuit and a planar microstrip antenna array have been fabricated on highly insulating silicon substrates. For the oscillator, a combined monolithic-hybrid integration technique was used to attach the discrete IMPATT diode to the resonator circuit. The oscillator does not require tuning elements. Preliminary experimental results are 8 mW of output power with 0.2 percent efficiency at 95 GHz.

Characteristics of a radial line slot antenna for 12 GHz band satellite TV reception

Abstract: Characteristics of a novel planar antenna which can radiate a circularly polarized pencil beam in x -band are presented for the application of receiving direct broadcast from a satellite. This antenna belongs to a class of slotted waveguide antennas and promising performances, especially its high efficiency, have already been predicted theoretically. The measured performance of a model antenna with a diameter of 0.6 m, is presented. Antenna gain of about 35 dBi and axial ratio of about 1 dB are realized at 12.2 GHz; the associated antenna efficiency of 57 percent is very high in comparison with that of the conventional microstrip antennas, in this range of gain.

Conformal antenna and method

Abstract: An antenna assembly and a method for mounting an antenna element in full conformity to a substantially curved surface are disclosed. The method includes the steps of providing a first, relatively thin dielectric substrate portion having an antenna element formed on a surface thereof; providing a second, relatively thick dielectric substrate portion; shaping and securing the second substrate portion to the curved surface; and shaping and securing the first substrate portion and the antenna element to the second substrate portion. The method permits a microstrip antenna, or other thin structure supported on a substrate, to be mounted to curved surfaces of even short radius or curvature (e.g., less than four inches) in full conformity therewith without damaging the thin fragile antenna element.

Dual band slotted microstrip antenna

Abstract: A dual band microstrip antenna including a slotted microstrip radiating pllel to and spaced from a ground plane with dielectric material therebetween, the slotted microstrip radiating and having a first resonance corresponding to the dominant radiation mode that would occur in an unslotted microstrip and a second resonance created by the slot. The polarizations of the two resonances are perpendicular to each other with the slot resonance being polarized along the centerline of the slot.

Input impedance of a probe-fed circular microstrip antenna with thick substrate

Abstract: A method of computing the input impedance for the probe fed circular microstrip antenna with thick dielectric substrate is presented. Utilizing the framework of the cavity model, the fields under the microstrip patch are expanded in a set of modes satisfying the boundary conditions on the eccentrically located probe, as well as on the cavity magnetic wall. A mode-matching technique is used to solve for the electric field at the junction between the cavity and the coaxial feed cable. The reflection coefficient of the transverse electromagnetic (TEM) mode incident in the coaxial cable is determined, from which the input impedance of the antenna is computed. Measured data are presented to verify the theoretical calculations. Results of the computation of various losses for the circular printed antenna as a function of substrate thickness are also included.

Dual frequency microstrip patch antenna with improved feed and increased bandwidth

Abstract: A dual frequency stacked microstrip patch antenna is comprised of a pair of circular radiating patches separated by a layer of dielectric, the two upper patches being further separated by another layer of dielectric from a pair of separated ground planes. A modal shorting pin extends between the patches and ground planes, and the patches are fed through a pair of feed pins by a backward wave feed network. A pair of pear-shaped holes in the lower patch through which the feed pins pass balance the impedance between the patches and result in an extended bandwidth.

Analysis of arbitrarily shaped microstrip patch antennas using segmentation technique and cavity model

Abstract: Arbitrarily shaped microstrip patch antennas have been analyzed for resonant frequency, input impedance, and radiation patterns. The segmentation technique and the cavity model have been used for this purpose. The usefulness and the accuracy of the method are shown through comparison with experimental results for a rectangular ring antenna. The agreement is seen to be very good. Ihe method appears to be more efficient compared to those reported so far for arbitrary shapes. Moreover, feed reactance is built into the analysis. The method presented here can also be used to analyze microstrip antennas with various types of loadings, e.g., shorting pins, matched loads, etc.

Antenna with integral tuning element

Abstract: A patch antenna, which may be one element of an antenna array, is formed on one broad surface of a semiconductor plate. A ground plane is formed on the second broad surface. This semiconductor is doped in regions near a periphery of the patch to define a semiconductor PN junction have electrode contacts to the patch and to the ground plane. The junction has capacitance which tunes the patch antenna. The characteristics of the junction are controlled by bias to selectively tune the patch antenna. The bias is a direct voltage in one embodiment of the invention. In another embodiment, the junction work function itself provides a bias which is controlled by temperature control of the diode.

Experimental study of a microstrip array on high permittivity substrate

Abstract: The results of an experimental study of microstrip patch antennas on moderately thick (0.02-0.03 \lambda_{0} ) substrates with relative permittivities of 10 and 13 are reported. Measured input impedances are qualitatively similar to those of antennas on thinner substrates with lower \epsilon_{r} , but significant differences in resonant resistance are observed for probe-fed and microstripline-fed antennas. Radiation patterns of individual elements exhibit deep scallops that appear to be caused by surface wave diffraction at the edges of the substrate, but four-element monopulse patterns exhibit a usable main beam and tracking null.

A New Method for Measuring Dielectric Constant Using the Resonant Frequency of a Patch Antenna

Abstract: An analytical expression is given for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of a patch antenna. Based on this result, a new method is developed for the measurement of the dielectric constant of a thin slab substrate. Basically, the test equipment consists of a rectangular microstrip antenna the patch of which is fed either by a microstrip line or coaxial line. From the measured resonance parameters of the rectangular patch antenna, the dielectric constant can be easily obtained. The measured values of the present method are in agreement with the precision standard cavity resonator method. Accuracy of the dielectric constant so obtained is satisfactory.

Effect of substrate on the efficiency of an arbitrarily shaped microstrip patch antenna

Abstract: A general approach is presented for the determination of power radiated via the space wave and surface wave from the aperture of an arbitrarily shaped microstrip antenna. The magnetic current model is used for this, and the analysis is carried out in the Fourier domain to determine the effect of the substrate. It has been shown that, in the Fourier domain, the longitudinal components of electric and magnetic displacement vectors follow the transmission line equation and can be solved by inspection. An expression for total radiated power has been derived. The singularities of the integral for power radiation indicate the presence of surface wave modes, and the associated power has been obtained using a singularity extraction technique. The effect of the substrate on space wave power has also been determined. This theory has been applied to a rectangular patch antenna. The results are in conformity with those reported in the literature. It has been found that for the frequency range ( h/\lambda, ), the effect of dielectric substrate can be neglected.

Multioctave bandwidth log-periodic microstrip antenna array

Abstract: The application of the log-periodic technique to the series-fed electromagnetically coupled overlaidpatch array allows antennas with flat conformal characteristics and wide bandwidths to be obtained. A k-s analysis of this and other microstrip array types indicate that the microstrip patch is not an optimum element for log-periodic arrays and that direct connection will result in arrays having a limited bandwidth. The addition of series capacitance to the patch equivalent circuit, implemented by electromagnetic coupling, allows an optimum to be approached. Log-periodic overlaid patch array design and measured results for an array with a 4:1 bandwidth are presented. These, together with a transmission-line analysis, indicate the array-design trade offs available and that the ultimate bandwidth is limited primarily by changes in the input return loss and radiation pattern due to the use of uniform thickness substrates.

A planar version of a 4.0 GHz reactively steered adaptive array

Abstract: -A planar (two-dimensional) reactively steered adaptive array (RESAA) including a single active microstrip element and eight closely coupled parasitic microstrip elements has been designed and tested. Steering of a null toward a single incident jammer is accomplished by adaptive control of reactive terminations on the parasitic elements using a guided random search algorithm. The planar array can steer a null in both the elevation and azimuth directions with a depth of 30 dB.

A conformal cylindrical microstrip array for producing omnidirectional radiation pattern

Abstract: Radiation patterns of rectangular microstrip patches arranged circumferentially on a circular cylinder have been computed. Both the axial patches and circumferential patches have been used. It has been found that the number of circumferential patches required for a given ripple in gain pattern is considerably less, thus simplifying the feed network. Comparison with experimental measurements shows good agreement.

Experimental study on stacked triangular microstrip antennas

Abstract: The broadband behaviour of a pair of stacked triangular microstrip antennas is investigated experimentally. Recent experiments have shown that the bandwidth of a triangular microstrip antenna (TMA) can be broadened to as high as 17.5%.

Aperture-coupled microstrip antenna with a perpendicular feed

Abstract: A new technique is described for feeding printed antennas. A microstrip antenna on one substrate is coupled through an electrically small aperture to a microstrip feed line on a perpendicularly oriented substrate. No direct connection is made to the patch. Such a geometry allows two separate substrates to be used for the antenna and feed functions. Measurements of a prototype design are presented.

Numerical analysis of circular disk microstrip antennas with parasitic elements

Abstract: Efficient numerical analysis of double tuned circular disk resonators/radiators is described. This method is based upon the Hankel transform domain analysis. Several numerical examples of input voltage standing-wave ratio (VSWR) characteristics and radiation patterns are compared with available experimental data.

An update on microstrip antenna theory and design including some novel feeding techniques

Abstract: This article will review the development of microstrip antennas and arrays. Early design and analysis work will be discussed, along with the advantages and limitations of microstrip antennas. Characteristics such as bandwidth, mutual coupling, and polarization will be addressed, and some of the recent work related to these characteristics will be noted. The current state of analytical techniques will be discussed, as will the concepts of a monolithic phased array. Finally, some new ways of feeding microstrip antennas will be presented.

Microstrip balun-antenna apparatus

Abstract: An balun-antenna arrangement is provided which is capable of being fabricated on a printed circuit board by automated equipment. The balun-antenna includes a microstrip transmission line which is coupled to one end of a split microstrip transmission line having opposed ends. An antenna which is symmetric about its feedpoint is coupled to the remaining end of the split microstrip transmission line.

Dual band antennas with microstrip array mounted atop a slot array

Abstract: A primary slotted array antenna operates at 10 GHz. In front of the primary antenna there is disposed a secondary antenna which operates at 1 GHz and is substantially transparent at 10 GHz. The secondary antenna is formed by an array of patch radiators and a transmission line feed network. The radiators and feed network are all formed by a conductive grid sandwiched between dielectric layers and designed to achieve the transparency at 10 GHz. At 1 GHz the grid appears as a continuous conductor forming one conductor of a microstrip transmission line. The other conductor (ground plane) is formed by the conductive front surface of the primary antenna. The grid/dielectric sandwich is suitably spaced from the ground plane by low dielectric pads. Other embodiments use slotline or coplanar stripline techniques. The ground plane may be an integral part of the secondary antenna, also constructed to be transparent at primary frequency.

Compact broadband microstrip antenna

Abstract: The development of a compact broadband microstrip antenna configuration is presented. The system uses a number of parasitic elements which are gas-coupled to a driven patch. The enhancement of bandwidth does not cause deterioration of the radiation pattern of the system.