Showing papers on "Microstrip antenna published in 1990"
TL;DR: In this article, a direct three-dimensional finite-difference time-domain (FDTD) method is applied to the full-wave analysis of various microstrip structures and antennas.
Abstract: A direct three-dimensional finite-difference time-domain (FDTD) method is applied to the full-wave analysis of various microstrip structures. The method is shown to be an efficient tool for modeling complicated microstrip circuit components and microstrip antennas. From the time-domain results the input impedance of a line-fed rectangular patch antenna and the frequency-dependent scattering parameters of a low-pass filter and a branch-line coupler are calculated. These circuits were fabricated and the measurements made on them are compared with the FDTD results and shown to be in good agreement. >
646 citations
TL;DR: In this paper, the characteristics of two-layer electromagnetically coupled rectangular patch antennas were investigated and the relative sizes of the parasitic and fed patches were found to have significant effects on the resonant input resistance and bandwidth.
Abstract: Experimental results on the characteristics of two-layer electromagnetically coupled rectangular patch antennas are presented. In addition to the relatively large bandwidth region that occurs when the separation between the two layers is less than 0.15 wavelength, a high-gain region is found when the separation exceeds 0.3 wavelength. The relative sizes of the parasitic and fed patches are found to have significant effects on the resonant input resistance and bandwidth. >
197 citations
Book•
01 Sep 1990TL;DR: In this article, the Smith chart and its uses hybrid-line couplers parallel-coupled lines and directional coupling filters are used for characterization of microstrip circuits and subsystems microstrip experiments.
Abstract: Transmission line theory two-port parameters microstrip transmission lines - basic theory microstrip transmission lines - further considerations discontinuities the Smith chart and its uses hybrid-line couplers parallel-coupled lines and directional couplers filters miscellaneous components active circuit characterization microstrip circuits and subsystems microstrip experiments.
178 citations
TL;DR: In this paper, a practical antenna configuration for use at microwave and millimetre wave frequencies is investigated, which consists of a circular cylindrical dielectric resonator fed by a microstrip feedline through a coupling aperture in the ground plane between them.
Abstract: A practical antenna configuration for use at microwave and millimetre wave frequencies is investigated. It consists of a circular cylindrical dielectric resonator fed by a microstrip feedline through a coupling aperture in the ground plane between them. Several elements, with different physical parameters, operating between 14 and 16GHz were constructed and tested. Experimental results confirm the effective and practical performance of the antenna structure.
168 citations
TL;DR: An analytic model for computing the radiation properties of the quadrifilar helix volute antenna is discussed and various design considerations for GPS applications are presented.
Abstract: An analytic model for computing the radiation properties of the quadrifilar helix volute antenna is discussed and various design considerations for GPS applications are presented. The effects of modifying the antenna length and diameter on the antenna amplitude and phase performance are presented, and using the antenna for dual-frequency operation is discussed. The effects of phase imbalances are presented and compared with measured pattern anomalies. >
157 citations
TL;DR: The feasibility of printed antennas which meet all the criteria for satellite communications antennas is considered in this paper, where a bandwidth greater than 20% for a VSWR of less than 1.5, crosspolar level lower than −30 dB over 20° solid angle, and gain better than 8 dB throughout the bandwidth is considered.
Abstract: The feasibility of printed antennas which meet all the criteria for satellite communications antennas is considered. These criteria are a bandwidth greater than 20% for a VSWR of less than 1.5, crosspolar level lower than −30 dB over 20° solid angle, and gain better than 8 dB throughout the bandwidth.
150 citations
TL;DR: In this article, the equivalence principle is used to predict the radiation pattern of a general class of leaky-wave antennas, consisting of a finite-size source which excites a radially propagating leaky wave on some planar surface.
Abstract: Formulas are derived for the far-infrared radiation pattern of cylindrical leaky waves propagating on a planar surface. The formulas can be used to predict the radiation pattern of a general class of leaky-wave antennas, consisting of a finite-size source which excites a radially propagating leaky wave on some planar surface. Leaky-wave antennas consisting of antenna elements embedded in dielectric layers (microstrip elements) fall into this category. Using the equivalence principle, formulas are derived for both transverse electric (TE) and transverse magnetic (TM) leaky waves with arbitrary propagation constants. The formulas allow for radiation from cylindrical apertures of arbitrary size, so that the effect of truncating the supporting planar surface with an absorbing material can be determined. Particular attention is devoted to the case of a leaky wave for which the real and imaginary parts of the complex propagation constant are equal, since this type of wave has been shown to be responsible for broadside radiation in certain leaky-wave antennas comprised of dielectric layers. >
146 citations
TL;DR: In this paper, the current distribution on the patch is rigorously formulated using a cylindrically stratified medium approach, and a set of vector integral equations is derived which governs the current distributions on a patch.
Abstract: The radiation from a cylindrical microstrip antenna excited by a probe is analyzed. Both the cylindrical-rectangular and the wraparound elements are discussed. The current distribution on the patch is rigorously formulated using a cylindrically stratified medium approach. A set of vector integral equations is derived which governs the current distribution on the patch. The set of equations is then solved using a moment method. The input impedance and the radiation pattern are derived both exactly and in the small substrate thickness limit. >
144 citations
TL;DR: In this article, two techniques are presented for the analysis of electromagnetic radiation and scattering from finite microstrip structures, based on two different formulations, viz. the volume-surface and surface-surface formulations.
Abstract: Two techniques are presented for the analysis of electromagnetic radiation and scattering from finite microstrip structures. The two techniques are based on two different formulations, viz. the volume-surface and surface-surface formulations. In the volume-surface formulation the finite-sized dielectric is replaced by an equivalent volume polarization current whereas the conducting plates are replaced by equivalent surface currents. For the surface-surface formulation the surface covering the dielectric volume is replaced by equivalent electric and magnetic currents and the conducting plates by surface electric currents. Both techniques can be utilized for the analysis of arbitrarily shaped finite microstrip structures. The techniques are quite accurate, and they are utilized to validate each other. Typical numerical results are presented to demonstrate the agreement between these two solution techniques. >
126 citations
Patent•
28 Aug 1990
TL;DR: In this paper, single or multiple players of electrically insulating tape have adhesive applied to one surface for the dielectric of the patch antenna, and the antenna structure can then be mounted to the desired surface by means of structural tape adhesives.
Abstract: Single or multiple players of electrically insulating tape have adhesive applied to one surface for the dielectric of the patch antenna. Electrically conductive foil tape with adhesive applied to one surface is used to create the radiating element and the ground plane. The antenna structure can then be mounted to the desired surface by means of structural tape adhesives. The resultant sandwich structure forms a highly flexible, low profile, low cost, rugged conformal antenna for radiating radio frequency energy. Modification and control of the electrical and performance characteristics of the antenna can be accomplished by non-uniform thickness of the dielectric, using insulating tape sections which differ in dielectric constant, incorporating PIN diodes with optical of electrical control, etc.
122 citations
TL;DR: In this paper, the authors discussed the factors affecting the realizable sidelobe performance of microstrip arrays, including excitation amplitude and phase accuracies, mutual coupling, diffraction effects, positioning errors and errors due to imperfect element matching and feed network isolation.
Abstract: The factors affecting the realizable sidelobe performance of microstrip arrays are discussed and quantified. These include excitation amplitude and phase accuracies, mutual coupling, diffraction effects, positioning errors, and errors due to imperfect element matching and feed network isolation. It is shown that low-sidelobe microstrip arrays require a very tight tolerance on the resonant frequencies of the elements, and the elimination of spurious radiation from the feed network. Cross-polarization and surface wave effects are discussed. An experimental 16-element microstrip array prototype incorporated these considerations into the design, and achieved a -35 dB relative sidelobe level. >
TL;DR: In this article, the resonance frequency of coax-fed circular microstrip antennas with and without air gaps has been modeled (in its Section III) by incorporating and rearranging some results previously reported by others.
Abstract: For original paper by Abboud et al. see IEEE Trans. Antennas Propagat., vol.38, p.1882-5 (1990). In the original paper, the resonance frequency of coax-fed circular microstrip antennas with and without air gaps has been modeled (in its Section III) by incorporating and rearranging some results previously reported by others. The present author, while working with the formulas of that Section III noticed a discrepancy in (8) and (9). This has been investigated thoroughly and the observations are presented. A brief reply is given by Damiano et al.
TL;DR: In this paper, a microstrip antenna with large bandwidth was developed using a parasitic technique, which gave a less distorted radiation pattern with frequency and achieved an impedance bandwidth eight times that of a conventional patch antenna of the same size.
Abstract: A microstrip antenna with large bandwidth is developed using a parasitic technique. Compared to the available wideband antennas, the proposed antenna structure is very compact and gives a less distorted radiation pattern with frequency. An impedance bandwidth eight times that of a conventional patch antenna of the same size is achieved. The concept of coupled microstrip line model is extended for theoretical interpretation of the impedance loci. The experimental procedure and results are described, and a theoretical analysis is presented. >
TL;DR: In this article, an E-field integral equation for the analysis of finite printed circuit antennas with multiple dielectric regions is developed, where the ground plane is considered to be finite.
Abstract: An E-field integral equation for the analysis of finite printed circuit antennas with multiple dielectric regions is developed. In this analysis, the ground plane is considered to be finite. The dielectric substrates may be either lossless or lossy, and they may be inhomogeneous but must be finite. The equivalence principle is used to replace all conducting bodies by equivalent surface electric currents and all dielectrics by equivalent volume polarization currents. The respective boundary conditions on the dielectrics and the conductors are utilized to solve for the electric current on the entire structure. Typical results are presented to illustrate the potential of this method. >
TL;DR: In this paper, the authors explored the characteristics of space and surface-wave fields produced by an electromagnetic source in a multilayered structure using the integral transformation technique, and showed that the space and the surface wave modes are orthogonal along the longitudinal direction with respect to an appropriate weighting function.
Abstract: Characteristics of space- and surface-wave fields produced by an electromagnetic source in a multilayered structure are explored. Using the integral transformation technique it is shown that the space and surface-wave modes are orthogonal along the longitudinal direction with respect to an appropriate weighting function. It is demonstrated that these properties, together with reciprocity, can be utilized to determine the amplitudes of various surface-wave modes produced by an arbitrarily shaped source. Numerical results for the space- and surface-wave power for a circular patch antenna are presented. The study may find application for millimeter-wave printed antennas where the surface waves will play an important role in determining the radiation and impedance characteristics. >
TL;DR: In this article, a full-wave analysis for determining the resonant frequency of a rectangular microstrip patch on multiple uniaxial anisotropic layers with or without ananisotropic overlay is presented.
Abstract: A full-wave analysis for determining the resonant frequency of a rectangular microstrip patch on multiple uniaxial anisotropic layers with or without an anisotropic overlay is presented. Two independent methods are used to derive the immittance matrix for the patch, from which the resonant frequency is determined. They are the Hertz vector potentials and the modified spectral domain immittance approach. Numerical results of the resonant frequency are given for several patch configurations, including cases of a patch on a single anisotropic layer, a patch on a double layer with one layer anisotropic and one layer isotropic, a suspended patch resonator with anisotropic substrate, a patch with anisotropic overlay and a patch on two anisotropic substrates with an anisotropic overlay. Changes in the resonant frequency of up to 58% are reported as n/sub x//n/sub y/ is changed from 1.0 (for isotropic substrates) to 2.0. >
TL;DR: In this article, a relatively simple closed-form asymptotic representation for the single-layer microstrip dyadic surface Green's function is developed, which is surprisingly accurate even for very small (a few tenths of a free-space wavelength) lateral separation of the source and field points along the air-dielectric interface.
Abstract: A relatively simple closed-form asymptotic representation for the single-layer microstrip dyadic surface Green's function is developed. The large parameter in this asymptotic development is proportional to the lateral separation between the source and field points along the air-dielectric interface. This asymptotic solution remains surprisingly accurate even for very small (a few tenths of a free-space wavelength) lateral separation of the source and field points. Thus, using the present asymptotic approximation of the Green's function can lead to a very efficient moment method (MM) solution for the currents on an array of microstrip antenna patches and feed lines. Numerical results based on the efficient MM analysis using the present closed-form asymptotic approximation to the microstrip surface Green's function are given for the mutual coupling between a pair of printed dipoles on a single-layer grounded dielectric slab. The accuracy of the latter calculation is confirmed by comparison with numerical results based on a MM analysis which employs an exact integral representation for the microstrip Green's function. >
TL;DR: In this article, an analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented, where the induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of a patch.
Abstract: An analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented. The induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of the patch. The radiated fields contributed by the induced current on the ground plane and the equivalent sources on the physical aperture yield the radiation pattern of the antenna. Radiation patterns of the circular patch with finite ground plane size are computed and compared with the experimental data, and the agreement is found to be good. The radiation pattern, directive gain and input impedance are found to vary widely with the ground plane size. >
TL;DR: In this paper, a method based on the mixed potential integral equation for the analysis of flat microstrip antennas in a double-layer substrate is presented, which is used to compute the input impedance of a stacked patch configuration.
Abstract: A method based on the mixed potential integral equation for the analysis of flat microstrip antennas in a double-layer substrate is presented. The method is used to compute the input impedance of a stacked patch configuration. This structure permits a larger bandwidth and may also provide dual-frequency operation. The Green's functions are discussed in detail, and numerical results are obtained for the propagation constant of the dominant surface wave. Theoretical and experimental results are compared for a dual-frequency and a broadband stacked patch antenna. Theoretical results for the input impedance are in good agreement with measurements. The difference between theoretical and experimental results for the resonant frequency is less than 4.5% in all cases. >
TL;DR: In this paper, a closed-form expression for the radiation efficiency of an arbitrary printed antenna element is presented, which is an improvement over those which have previously appeared, and the results are shown to be tight.
Abstract: Rigorous closed-form expressions are presented for the radiation efficiency of an arbitrary printed antenna element. These results are an improvement over those which have previously appeared.
TL;DR: In this article, a simple theory based on the cavity model was developed to analyze microstrip antennas excited by a slot in the ground plane, and the loci of the slot feed location for achieving the circular polarization and the input impedance were computed and found to be in excellent agreement with the experimentally measured results.
Abstract: A simple theory based on the cavity model is developed to analyze microstrip antennas excited by a slot in the ground plane. By using an equivalent magnetic current source at the feed, the electric field under the patch is obtained in terms of a set of cavity modes. In particular, the loci of the slot feed location for achieving the circular polarization and the input impedance are computed and found to be in excellent agreement with the experimentally measured results. Simple but surprisingly accurate formulas for slot-fed circularly polarized microstrip antennas are derived and compared with those for probe-fed counterparts. >
TL;DR: Graphical guidelines for design of electromagnetically coupled square and circular microstrip antennas are given in this paper, where the design data are computed by applying the method of moments in the spectral domain to solve the integral equation for the currents on the patch and portion of the microstrip feed line.
Abstract: Graphical guidelines for design of electromagnetically coupled square and circular microstrip antennas are given. Substrates composed of two different dielectric layers are considered. The analysis is extended to electrically thick substrates. Given the required resonant frequency and the bandwidth, material parameters are selected. Patch dimension and the optimal position of the feed line are obtained from the provided graphs. The design data were computed by applying the method of moments in the spectral domain to solve the integral equation for the currents on the patch and portion of the microstrip feed line. The integral equation was formulated using the appropriate dyadic Green function for the grounded multilayered slab. >
TL;DR: In this paper, a multifunctional aperture coupled stacked patch antenna is presented that operates at dual frequency bands at the lower frequency band and at the higher frequency band at the same time.
Abstract: A multifunctional aperture coupled stacked patch antenna is presented that operates at dual frequency bands. At the lower frequency band, the antenna exhibits a 2:1 VSWR bandwidth of 20%, and at the higher frequency band, it behaves like a conventional narrowband patch antenna with a 2:1 VSWR bandwidth of 3%. Measured VSWR and far-field radiation patterns as well as numerical predictions are presented. A proper choice of the patch dimensions has been found critical to achieve this multifunctional performance.
Patent•
06 Dec 1990TL;DR: In this paper, an angular rate sensor is mounted inside a microstrip antenna to detect the state of turn in a mobile and to control the beam direction of the antenna in accordance with the state-of-turn as well as the strength of radiowave received by a receiver in the mobile.
Abstract: In mobile communications, it is required that the beam direction is maintained to track the desired direction as the mobile is moving. For such a purpose, the mobile includes an angular rate sensor mounted therein which detects the state of turn in the mobile and to control the beam direction of the antenna in accordance with the state of turn as well as the strength of radiowave received by a receiver in the mobile. Antenna elements (114) are in the form of microstrip antenna and are arranged in plane on the same dielectric substrate (113 or 112). Feeding and drive circuit layers (122, 124) for controlling the transmission and reception at the antenna elements are stacked into a single layered unit. This enables the antenna system to be formed into a low-profile structure. The dielectric substrate of the microstrip antenna element is formed by stacking a plurality of dielectric substrates (112, 113) different in dielectric constant from one another. It is thus intended that the band width of the antenna is increased and that the mutual coupling between the antenna elements is reduced to prevent the gain of the antenna from being lowered. Furthermore, the position of feed points in the antenna element are rotated against each adjacent antenna element. This can improve the axial ratio in the array antenna over a wide band width.
Patent•
08 Jun 1990TL;DR: In this article, a microstrip antenna including a patch radiator with parasitic elements, flush-mounted and conforming to the side of the missile, producing an antenna beam which is tilted in required direction for use as a link or fuse antenna is shown.
Abstract: In a guided missile, a microstrip antenna, including a patch radiator with parasitic elements, flush-mounted and conforming to the side of the missile, producing an antenna beam which is tilted in required direction for use as a link or fuse antenna is shown Parasitic elements are used to direct the beam away from the antenna normal to the desired direction
01 Jun 1990
TL;DR: In this paper, a study of multilayer microstrip antennas fed by coaxial probe or microstrip line is presented, which is applicable to structures with stacked or offset radiating elements of various shapes including rectangles, discs and triangles.
Abstract: A study of multilayer microstrip antennas fed by coaxial probe or microstrip line is presented. The method developed is applicable to structures with stacked or offset radiating elements of various shapes including rectangles, discs and triangles. Theoretical and experimental results of input impedance are given for the different structures. Radiation information is presented and the relative merits of different structures are discussed.
01 Jan 1990
TL;DR: In this paper, a new model for calculating the input impedance of a probe-fed circular antenna with and without air gaps between the substrate and the ground plane is presented, based on the cavity model, the dynamic permittivity constant (to take into account the in- fluence of the fringing field at the edge of radiating element), and the resonant parallel R -L -C circuit with an inductive reactance.
Abstract: A new model is presented for calculating the input impedance of a probe-fed circular antenna with and without air gaps between the substrate and the ground plane. It is based on the cavity model, the dynamic permittivity constant (to take into account the in- fluence of the fringing field at the edge of radiating element), and the resonant parallel R -L -C circuit with an inductive reactance. Numerical results are compared with experimental ones. This model is well suited for computer-aided design.
TL;DR: In this paper, a general scattering formula is derived for an arbitrary resonant conductive body within a layered medium, which shows that the body radar cross section is directly related to the radiation efficiency of the body.
Abstract: A general scattering formula is derived for an arbitrary resonant conductive body within a layered medium, which shows that the body radar cross section (RCS) is directly related to the radiation efficiency of the body. The radar cross section of a rectangular microstrip patch antenna in a lossy substrate-superstrate configuration is then investigated as a specific case. Results are presented to show the effects of loss in the substrate, a lossless superstrate, and a lossy superstrate. >
TL;DR: In this paper, a finite-difference time-domain (FDTD) technique is used to analyze boxed microstrip with both rectangular and trapezoidal cross-sections and it is confirmed that the exact shape of the conductor has a marked effect on the effective permittivity.
Abstract: The finite-difference time-domain (FDTD) technique is used to analyze boxed microstrip with both rectangular and trapezoidal cross sections. It is confirmed that the exact shape of the conductor has a marked effect on the effective permittivity of the microstrip. Results using this method are compared to the findings of K.A. Michalski et al. (1989) using the analytically more complicated boundary element method; very good agreement is observed. The effect of adding a thin passivation layer is also calculated and it is found that such an addition noticeably reduces the effective permittivity of the microstrip. It is shown that the FDTD technique is capable of treating microstrip with a general cross section and producing accurate results. >
TL;DR: An analysis is presented of the radiation properties of infinite phased arrays of one- or two-probe-fed circular microstrip patches, using a rigorous Green's-function/moment-method approach.
Abstract: An analysis is presented of the radiation properties of infinite phased arrays of one- or two-probe-fed circular microstrip patches, using a rigorous Green's-function/moment-method approach. Two ways of treating the connection of a vertical feed probe to the patch are considered: an idealized probe feed model, which is useful for antennas printed on thin substrates or to predict general performance trends, and a more rigorous treatment that overcomes the deficiencies of the simpler model. This rigorous treatment seems to have some advantages over other published analyses, including applicability to a wide range of printed radiator problems, but requires a huge increase in the amount of computer time required for the calculation. Comparisons of both feed models with measured data from waveguide simulators are used to validate the theory for both one- and two-probe-fed elements. >