Showing papers on "Microstrip antenna published in 1975"

Equations for Microstrip Circuit Design

Abstract: A method for determining the accuracy of computed impedance and wavelength data for microstrip is proposed. It is shown that the standard equations of Wheeler and Schneider have rather large errors. Revised equations for microstrip impedance and wavelength are given both for analysis and synthesis with accuracy better than 1%. A simple, accurate equation for the microstrip open circuit is presented. Experimental data on microstrip T-junctions are compared with existing theories. A new accurate equation is given for the reference plane displacement in the stub arm. Corrections are proposed in the existing equations for the other parameters of the equivalent circuit.

Two methods for the measurement of antenna efficiency

Abstract: Two methods for measuring antenna efficiency are described. The two methods, referred to as the Wheeler method and the Q method, are used to find the efficiency of electrically small multiturn loop antennas. The principal advantage of both methods is that they can be quickly and easily applied. Further, both methods relate the antenna efficiency to the input impedance rather than a far-field pattern integration. Thus, the methods are applicable at VHF and frequencies below where the design of an antenna range or anechoic chamber becomes increasingly difficult and expensive.

Microstrip-dipole antenna elements and arrays thereof

Abstract: Herein disclosed are antenna elements comprised of a dipole reactively coupled to a feed line on a microstrip board; and linearly and circularly polarized arrays of such elements.

Three-Dimensional Transmission-Line Matrix Computer Analysis of Microstrip Resonators

Abstract: A wide range of microwave resonators are analyzed using the same three-dimensional transmission-line-matrix (TLM) computer program. The paper demonstrates the ease of application, versatility, and accuracy of the TLM method. The results presented include the dispersion characteristics of microstrip on dielectric and magnetic substrates and an example of a microstrip discontinuity. The surface-mode phenomenon of microstrip is also investigated.

Multiple resonance radio frequency microstrip antenna structure

Abstract: A multiple resonance microstrip antenna radiator which includes a plurality of stacked electrically conductive element surfaces disposed above an electrically conductive reference surface with each element surface dimensioned so as to resonate at a different radio frequency. The various element surfaces are spaced one from another and from the reference surface with a dielectric material and an rf feed is attached to at least one of the element surfaces. Non-resonant element surfaces provide inductive capacitive coupling of rf energy to/from a resonant element surface.

Asymmetrically fed electric microstrip dipole antenna

Abstract: An asymmetrically fed electric microstrip dipole antenna consisting of a n electrically conducting, rectangular-shaped element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface The length of the element determines the resonant frequency The feed point is located along the centerline of the antenna length and the input impedance can be varied by moving the feed point along the centerline from the center point to the end of the antenna without affecting the radiation pattern The antenna bandwidth increases with the width of the element and spacing between the element and ground plane

Volume-type holographic antenna

Abstract: A new type of holographic antenna based on the principle of the volume hologram is proposed. The characteristics of the prototype are examined. The antenna has a unidirectional beam with a front-to-back ratio of 20 dB. The practical frequency handwidth is about 10 percent of the center frequency. The antenna is unique in that the feed point is placed in the plane of the holographic plate so that both feeder and the holographic plate could be made out of one printed circuit board for easy flush mount installation or mass production, although the feeder of the prototype antenna was a pyramidal horn.

Microstrip antenna structure

Abstract: A microstrip antenna radiator is disclosed which includes three edges spaced around its periphery defining three corresponding active slot areas wherein each slot has a different respectively corresponding resonant dimension associated therewith along a direction substantially transverse to the edge which defines the radiating slot. At least two dimensions of an essentially equilateral triangular shape are altered so as to provide the three different resonant dimensions for the radiator. Typically, at least two sides of such a triangular structure are altered such as by the formation of tab extensions or, alternatively, at least two apices of the basic triangular structure are truncated so as to produce different resonant dimensions in the radiator. Various combinations and permutations of such shape alterations may also be employed. Such a triangular microstrip radiator is especially adapted for elliptical or circular polarization and for utilization in arrays of such polarized elements wherein the triangular shape of each element permits a more nearly optimum spacing of the individual elements within one or more arrays.

Dual frequency microstrip antenna structure

Abstract: A conformal microstrip antenna structure formed by a plurality of separated spaced-apart electrically conducting elements on a dielectric substrate overlying a ground plane. The innermost edges of the separated conducting elements define two sets of two intersecting radiators which are fed by microstrip transmission circuits disposed within the space between the separated conducting elements to individually feed the various radiators and/or segments thereof from the common feed point. The dimensions of the conducting elements also determine the resonant frequency of the radiators and their relative phases such that dual frequency operation as well as circular and/or elliptical polarization of the received/transmitted electromagnetic radiation can be conveniently achieved.

Evaluation of the Equivalent Circuit Parameters of Microstrip Discontiuuities through Perturbation of a Resonant Ring (Short Papers)

Abstract: A resonant technique for evaluating the equivalent circuit of reciprocal microstrip discontinuities is described. The complex Z parameters of a discontinuity are related to the change in resonant frequencies and Q factors of a microstrip ring it perturbs. As an example, measurements made on inductive posts are presented and compared with theoretical values.

Millimeter waveguide to microstrip transition

Abstract: A waveguide to microstrip transition apparatus in which a waveguide coupledo a microstrip circuit is provided with a mode filter for suppressing spurious modes of electromagnetic signal propagation. The mode filter is attached to the end of the waveguide that is coupled to the microstrip circuit and the mode filter extends over a portion of the microstrip circuit.

Conformal radar antenna

Abstract: A conformal electronically scanned antenna array system utilizing an inve Butler matrix in combination with directive antenna elements. The system provides a simple and inexpensive device for scanning an elemental array without the problems of output frequency shift or mutual coupling between antenna elements.

Notch fed electric microstrip dipole antenna

Abstract: A notch fed electric microstrip dipole antenna consisting of a thin electally conducting, rectangular-shaped element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The length of the element determines the resonant frequency. The feed point is located in a notch along the centerline of the antenna length and the input impedance can be varied by moving the feed point along the centerline of the antenna without affecting the radiation pattern. Of all the many types of microstrip antennas built to date, this antenna offers the best advantages as far as arraying of the elements are concerned. The notched antenna can be arrayed using microstrip interconnecting transmission lines. The corner losses in the clad material and the width of the notch determines how narrow the element can be made. The purpose of the notch feed system is to interconnect any array of elements at the elements' optimum feed point using microstrip transmission lines.

Low-profile quadrature-plate UHF antenna

Abstract: A low-profile UHF antenna comprises two orthogonally positioned parallel te radiators that are semi-circular in shape. The base of each radiator (filled with dielectric material) is connected to a circular metal ground plane. The radiators can be collectively excited with a single input feed or they can be independently excited in any phase relationship for changing direction or polarization of the radiation field. Thus, the antenna is capable of operating in either a linear or circular polarization mode. The antenna can also be switched rapidly from one linear polarization to a second linear polarization in a perpendicular plane by using techniques familiar to the art.

New Design Techniques for Microstrip Antenna Arrays

Abstract: The radiation resistance of an open-circuit microstrip termination is to a good approximation, a simple function of the strip width thus suggesting a straightforward yet effective means of element control when used in a large array; furthermore the array bandwidth can be controlled to some extent. The design of linear and two dimensional resonant arrays based on this design procedure is formulated and examples at X and J band are outlined; the beamwidths and sidelobe levels are of the order ± 4.5° and -16dB respectively. The extension of the new technique to travelling wave arrays, circular polarisation and various substrates is under investigation and will be mentioned; computational aspects throughout will be discussed.

Dual slot microstrip antenna device

Abstract: A dual slot antenna assembly is disclosed herein and generally includes a pair of concentrically positioned and radially spaced cylindrical conductors defining a pair of circumferential slots which are longitudinally spaced one-half wavelength apart at the anticipated operating frequency of the antenna device. An electrical signal feed assembly is connected with the conductors for exciting the slots so as to provide overlapping radiation patterns emanating in the same direction.

Diagonally fed electric microstrip dipole antenna

Abstract: A diagonally fed electric microstrip dipole antenna consisting of a thin ctrically conducting, rectangular-shaped element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The length of the element determines the resonant frequency. The feed point is located along the diagonal with respect to the antenna length and width, and the input impedance can be varied to match any source impedance by moving the feed point along the diagonal line of the antenna without affecting the radiation pattern. The antenna bandwidth increases with the width of the element and spacing between the element and ground plane. Singularly fed circular polarization is easily obtained with this antenna.

Tapered Asymmetric Microstrip Magic Tee

Abstract: The design of a very compact decade (1 to 10 GHz) bandwidth, -8.34 dB microstrip coupler and magic tee is described. The coupling factor is calculated. The construction of the device is described and its feasibility demonstrated.

Method of making an antenna array using printed circuit techniques

Abstract: Radio frequency array antenna structures and methods for fabricating such structures are disclosed wherein a plurality of radio frequency circuits forming the radiating face of an array antenna and a corporate feed are formed on one or more relatively flexible dielectric sheets and then bonded to a suitable core material to form a complete array structure which is light weight, inexpensive and structurally sound.

The Microstrip Double-Ring Resonator (Short Papers)

Abstract: The resonance frequencies and the fields of a microstrip double-ring resonator are discussed. It is shown that no pure even or odd mode can be excited on the resonator. Therefore it is concluded that the rnicrostrip double-ring resonator principally cannot be used to measure the phase velocities of the even and the odd modes on a coupled microstrip line.

A scattering theory approach to the prediction of dielectric rod antenna radiation patterns: The TM 01 mode

Abstract: The shortcomings of both the surface integration and the two-aperture approach to the prediction of dielectric rod antenna patterns are well known. An alternative procedure based on a simplified scattering model is presented which is capable of yielding satisfactory results without the necessity of making empirical corrections.

End fed electric microstrip quadrupole antenna

Abstract: An end fed electric microstrip quadrupole antenna consisting of a thin elrically conducting, rectangular-shaped element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The feed point is located at one end of the centerline of the antenna length. The antenna bandwidth increases with the width of the element and spacing between the element and ground plane. The end fed microstrip quadrupole antenna operates in a degenerate mode, i.e., two oscillation modes occurring at the same frequency. Along the element length, the oscillation occurs in a dipole mode (fundamental mode) whereas along the element width the oscillation occurs in a quadrupole mode (higher order mode). The corners nearest the feed point may be used for fine tuning of the antenna by trimming small strips of copper from the corner.

Conformal antenna synthesis using spherical harmonic wavefunctions

Abstract: A new antenna-synthesis method is described that allows the antenna surface geometry to be arbitrarily specified and the radiating current distributions to be computed directly from the radiation patterns, which can be quite general and have any type of polarisation: this latter process makes the synthesis procedure nonunique, but is of great practical value since phase information is not required. Illustrative examples based on rotational symmetry are given to show the effect of all the various sources of controllable error, and useful information is also extracted about the formulation of active conformal arrays of small closely spaced noninteracting radiating elements; in particular, a means of optimising a conformal beacon antenna and creating a wide bandwidth supergain system by utilising the closely spaced driven array principle is discussed.

Tapered Asymmetric Microstrip Magic Tee (Short Papers)

Abstract: The design, development, and construction of a very compact decade-(1-10-GHz) bandwidth microstrip --8.34-dB coupler are described. Calculations are given for the voltage coupling coefficient and the low-frequency cutoff, and the method of determing the physical dimensions of the circuit is described. Also, the feasibility of a decade-bandwidth microstrip magic tee by cascading two -- 8.34-dB couplers is demonstrated by comparing the actual and theoretical results of a coupler.

Offset fed electric microstrip dipole antenna

Abstract: An offset fed electric microstrip dipole antenna consisting of a thin eleically conducting, element formed on one surface of a dielectric substrate, the ground plane being on the opposite surface. The length of the element determines the resonant frequency. The feed point is located along one edge of the antenna length and the input impedance can be varied by moving the feed point along the edge of the antenna to obtain optimum match for the resonant mode without affecting the radiation pattern. The antenna bandwidth increases with the width of the element and spacing between the element and ground plane. Slanting one end of the element will provide a slightly wider bandwidth.