Showing papers on "Microstrip antenna published in 1978"

A New Travelling Wave Antenna in Microstrip

Abstract: The radiation characteristics of the first higher order mode of microstrip lines are investigated. As a result, a simple travelling wave antenna element is scribed, having a larger bandwidth compared with resonator antennas. A method to excite the first higher order mode is shown. A single antenna element is treated theoretically and experimentally, and an array of four antenna elements is demonstrated.

A dual-frequency stacked circular-disc antenna

Abstract: The dual-frequency behavior of a pair of stacked circular-disc printed-circuit antennas is investigated experimentally. The input impedance is measured as a function of the sizes of the discs with emphasis placed on the values of the two resultant resonant frequencies.

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.

Antenna measurements—1978

Abstract: This paper discusses the techniques in antenna measurements and facilities which have evolved over the last decade. The facilities include the tapered anechoic chamber, the compact range, and the near-field probing range. The significant advances in obtaining improved measurement accuracy for power gain, polarization, and swept-frequency techniques are also discussed.

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.

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.

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.

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.

Theory of the circular-disc printed-circuit antenna

Abstract: A planar conducting structure, an electrically small distance above a ground plane, can be constructed to radiate in the direction normal to its plane while still retaining its low-profile characteristics. A circular disc structure is analysed theoretically to provide aid in the design of such antennas. The currents, fields, total radiated power, directive gain, losses, Q-factor and efficiency are all calculated at several frequencies for various values of the thickness, permittivity, and loss tangent of the dielectric material that separates the antenna from the ground plane.

Microstrip antenna with circular polarization

Abstract: A microstrip antenna is disclosed having an etched metal radiator element including a polarizing patch consisting of a two dimensional removal of metallization from the central portion of the radiator element with one dimension of the polarization patch being greater than the other dimension e.g. an elongated rectangle and selectively oriented with respect to the input axis whereby, for example, circular polarization is achieved by means of orienting the polarization patch substantially 45° with respect to the input axis.

Scattering by an infinite periodic array of microstrip elements

Abstract: An analysis of the scattering by an infinite periodic array of microstrip disks is made using a Galerkin solution of a vector integral equation. The solution is examined for convergence and compared with theory and experiment. The solution is used to minimize the loss and maximize the bandwidth of the element in a reflectarray configuration.

Electromagnetically Coupled Microstrip Dipole Antenna Elements

Abstract: An electromagnetically Coupled (EMC) member of the microstrip dipole antenna family is described. Several configurations differing in the dipole location and in the amounts of electric and magnetic coupling to the micro-strip line yield different bandwidths, efficiencies and construction simplicity. The transformer action inherent in EM coupling allows a wide variation in matching conditions. Radiation characteristics of the element and examples of arrays constructed with the element are described.

Terminated microstrip antenna

Abstract: A microstrip antenna design according to which a plurality of resonant frencies can be obtained for a given size radiator, to increase the usefulness of the antenna by providing for frequency diversity operation and by making the microstrip antenna tunable over a range of frequencies. As will be seen, the microstrip antenna is provided with an output termination which can be open-circuited or short-circuited, and at varying lengths, to change the frequency at which the microstrip antenna can be made resonant.

Radiation conductance of open-circuit low dielectric constant microstrip

Abstract: The existing discrepancies between formulas for the radiation conductance of an open-circuit microstrip line are investigated and comparison made with measurements of improved accuracy. It is found that consistent results are obtained if an allowance is made for field-fringing effects in those analyses based on radiation from apertures.

Microstrip antenna radiators with series impedance matching means

Abstract: One or more radiating elements are coupled to a source of microwave energy by one or more quarter-wave lines of alternately high and low characteristic impedance.

The performance of an iris-loaded planar phased-array antenna of rectangular waveguides with an external dielectric sheet

Abstract: A new method for calculating the performance of an iris-loaded planar phased-array antenna of rectangular waveguides is presented. The method is based upon the expansion of the tangential electric aperture field in terms of judiciously chosen functions. Also, the influence of a dielectric sheet in front of an antenna the apertures of which are loaded with inductive irises is investigated. In the experiments, a sheet with a low relative permittivity ( \epsilon_{r} = 2.3 or \epsilon_{r} = 3.5 ) is spaced in front of a space-fed planar antenna of some 850 radiating elements, and the total transmitted power of the antenna is measured as a function of frequency and scan angle. The results indicate, that both in theory and in practice, an excellent match can be achieved with a polythene sheet ( \epsilon_{r} = 2.3 ) or a Perspex sheet ( \epsilon_{r} = 3.5 ).

Parallel Line Microstrip Filters in an Inhomogeneous Medium

Abstract: Parallel coupled microstrip lines in an inhomogeneons medium are studied. The quasi-static capacitance is shown to be linear with regard to the dielectric constant epsilon/sub r/ simplifying the formalism used for analyzing microstrip filters. The electromagnetic advantages of the homogeneous medium carry over to the inhomogeneous medium. This result is obtained by equalizing all the velocities of the propagation modes.

A 36 GHz printed planar array

Abstract: The performance of a simple, low-cost, centre-fed, efficient planar array aerial for Q band is described. The microstrip radiating pattern is produced by conventional photolithographic techniques. Gains up to 25 dB with beamwidths of 8° and bandwidths of 500 MHz make this ‘flat’ aerial attractive for many industrial applications where space is limited.

Reactively loaded corner fed electric microstrip dipole antennas

Abstract: A corner fed electric microstrip dipole antenna consisting of a thin eleccally conducting, square 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 sides of the radiating element are all equal. The length of the element determines the resonant frequency along the Y axis and the width determines the resonant frequency along the Z axis. This antenna is capable of generating elliptical and circular polarized radiation when reactively loaded using a single element and single feed point.

Resonant length of a linearly polarised microstrip radiator

Abstract: A method for altering the resonant length of a square micro-strip antenna is described. The relevant analysis and computations have been carried out to propose a possibility of realising a microstrip antenna having comparatively smaller dimensions and larger bandwidth.

Microstrip network having phase adjustment

Abstract: In an array antenna system having a coupling network interconnecting a plurality of element groups, the coupling network is provided with phase adjustments to shift the angular location of the effective element radiation pattern. An effective technique for this phase adjustment in a microstrip coupling network makes use of a field altering structure positioned adjacent the microstrip.