Showing papers on "Coaxial antenna published in 1969"

Coaxial-line to waveguide transition for horn antenna

Abstract: THE INVENTION RELATES TO AN ANTENNA ASSEMBLY FOR MICROWAVE USAGE WHICH IS CHARACTERIZED BY A COAXIAL-LINE TO WAVEGUIDE TRANSITION. THE ANTENNA INCLUDES A RECTANGULAR WAVEGUIDE SECTION, A SECTORAL HORN, AND A TRANSFORMER FOR PROVIDING IMPEDANCE MATCHING BETWEEN THE WAVEGUIDE AND THE HORN. THE TRANSITION IS ACCOMPLISHED BY FEEDING TO THE END OF THE WAVEGUIDE AN E-PLANE LOOP, I.E., A LOOP PARALLEL TO THE ELECTRIC FIELD PLANE IN THE WAVEGUIDE. THE END FEEDING OF THE WAVEGUIDE RESULTS IN A MINIMUM VERTICAL DIMENSION OF THE OVERALL DEVICE WHEN THE COAXIAL LINE IS ATTACHED. THE SMALL VERTICAL DIMENSION IS DESIRABLE IN ORDER TO PERMIT STACKING OF A REQUIRED NUMBER OF ANTENNAS IN AN ARRAY HAVING LIMITED SPACE REQUIREMENTS BETWEEN ASSEMBLY INPUTS. THE INVENTION ALSO FEATURES A WIDE BAND RESPONSE.

Corporate-network printed antenna system

Abstract: A corporate-network printed antenna system is described wherein the feed lines are located in coplanar relationship with and in the field of the antenna.

Folded integrated antenna and amplifier

Abstract: An integrated antenna system comprising a ground plane, at least one vertical element substantially perpendicular to the ground plane, a helically shaped element having horizontal polarization and a solid state circuit located at the junction of the horizontal and vertical elements. The described antenna system facilitates control of the characteristics of the antenna without varying the physical dimensions thereof. Consequently, antenna size may be reduced, related equipment simplified and the overall characteristics of the antenna system improved.

Improved radiation from a spherical antenna by overdose plasma coating

Abstract: It is shown that the radiation from a plasma-coated spherical antenna can be enhanced if the antenna is operated at a frequency much lower than the plasma frequency, and if the dimensions of the antenna and the plasma layer are appropriately chosen. This phenomenon may prove useful for overcoming the blackout problem suffered by a reentry vehicle or may offer a novel method of low-loss tuning of a small antenna.

Cavity-backed spiral antenna with mode suppression

Abstract: THIS PLANAR UNIDIRECTIONAL CAVITY-BACKED SPIRAL ANTENNA HAS A CYLINDRICAL RESISTANCE CARD IN THE CAVITY COAXIAL WITH THE CENTER CONDUCTOR THEREOF TO SUPPRESS MODES OF PROPAGATION OF ELECTROMAGNETIC WAVES IN THE CAVITY OTHER THAN THE DOMINANT MODE.

Dual polarized antenna system with controlled field pattern

Abstract: A DIRECTIONAL ANTENNA SYSTEM PROVIDES BOTH VERTICAL AND HORIZONTAL POLARIZATION. A SPIRE NEAR THE TOP OF A SKYSCRAPER CARRIES A PAIR OF VERTICALLY ORIENTED DIPOLES ON OPPOSITE CORNERS. A POWER DIVIDER DELIVERS MORE ENERGY TO ONE OF THE DIPHOLES THAN TO THE OTHER. THE SPIRE ALSO CARRIES A SLOTTED RING ANTENNA HAVING FED DIRECTIONALIZING ELEMENTS AND COEXTENSIVE WITH AN EXTENSION OF ONE OF THE DIPOLES TO PROVIDE SUBSTANTIALLY THE SAME HORIZONTAL DIRECTIONALITY PATTERN FOR HORIZONTALLY POLARIZED ENERGY AS THE VERTICALLY ORIENTED DIPOLES PROVIDE FOR VERTICALLY POLARIZED ENERGY.

Dual mode conical horn antenna

Abstract: A circular rod having tapered ends is coaxially mounted within a conical horn antenna. When energy in the TE*11 mode is fed into the throat of the antenna, it transforms smoothly over the length of the rod into the hybrid HE*11 mode. At the antenna aperture, the energy again transforms and this time appears in correctly phased TE*11 and TM*11 modes.

Theoretical Study of Finite Dielectric‐Coated Cylindrical Antenna

Abstract: A finite cylindrical antenna which is imbedded in a concentric dielectric rod has been investigated by employing a rigorous formulation. When the antenna is relatively short, a numerical method is used; when the antenna is long, the Wiener‐Hopf technique is applied. In both cases the input admittance and the current distribution are obtained. It is found that the input conductances are larger than for the corresponding free‐space antennas, the field patterns tend to be more broadside and, as the antenna gets longer and longer, the locus of the input admittance becomes a circle instead of converging to one point as it does for a bare cylindrical antenna. The first method is applicable regardless of the thickness of the antenna and the dielectric rod; the second method can be applied only to a sufficiently long antenna. The minimum length is determined by the thickness of the dielectric rod. This study is limited to thin antenna in rather thick dielectric cylinders. However, the dielectric rod is still not thick enough to support a transverse magnetic (T.M.) mode.

An omnidirectional microwave antenna for use on spacecraft

Abstract: The qualitative theory, design, and development of a parallel-plate waveguide-fed antenna, suitable for flush-mounted broad-band spacecraft applications, are presented. The antenna makes use of wedge-like metal posts placed uniformly about the periphery of the feed plates to provide both structural strength and practical interconnection routes for cables without disrupting the antenna impedance and patterns. Measurements taken on the antenna, which is mounted on spheroids up to 50 wavelengths in circumference, are presented; equatorial patterns are omnidirectional within \pm 0.25 dB, and polar patterns have beam widths similar to a half-wave dipole.

A packaged antenna for short-hop microwave radio systems

Abstract: This paper describes a packaged antenna specially designed for mounting on a slender tapered aluminum mast and gives typical measured electrical characteristics. The antenna is used in a 1.5-mile experimental repeater installation operating at 11 GHz. The masts and foundations for the experimental system are described briefly. The antenna package is an upright cylinder, a shape chosen to minimize mast twisting caused by wind, and to present a pleasing appearance in combination with a slender mast. The radiating elements consist of a waveguide aperture feed, a 30-inch parabolic reflector mounted with its axis vertical at the top of the package, and a 45-degree flat reflecting plate similar to an inverted periscope. The space below the 45-degree reflector houses all the repeater electronics. Because of the shielding effect of the cylindrical housing, this antenna like the horn-reflector antenna, has very low radiation in the far side and back lobe regions.

Experimental radiation pattern of the corrugated conical-horn antenna with small flare angle

Abstract: An experimental study concerning the bandwidth of the conical horn antenna with small flare angle has been carried out. The conclusion is that such an antenna with small diameter has a symmetrical radiation pattern in a very small frequency range.

The Near Field of the Loop Antenna

Abstract: The near fields of a circular loop antenna have been evaluated and discussed for various size loops. The results are obtained in a form that is useful in predicting the microwave breakdown characteristics of the antenna.

Theoretical study of a cylindrical antenna with a hemispherical cap

Abstract: The integral equation of a cylindrical monopole antenna with a hemispherical cap driven by a coaxial line is formulated and solved by two approximations. First, the current on the cap is approximated by a sinusoidal distribution. Secondly, the field across the driven gap is approximated by the fundamental transverse electromagnetic (TEM) coaxial-line mode. Results are compared with the tubular model. It is shown that the input admittance curve of the capped antenna has the same shape as that of the tubular antenna with open ends but is shifted. The radiation patterns of the two antennas are essentially the same. The capped antenna is approximately equivalent to the tubular antenna with length 0.25 times the radius shorter than the total axial length of the antenna with a cap.

Tracking antenna system

Abstract: A tracking antenna system capable of detecting a difference between the direction of an incoming wave and that of the boresight axis of an aperture antenna of the system and capable of detecting the direction of polarization of the incoming signal. The system comprises a sampling coupler for selectively leading out a particular one of the higher modes excited in a circular waveguide connected with the antenna and comprises an angular error signal processing circuit in association with the sampling coupler.

Radar antenna radome construction

Abstract: A RADAR ANTENNA RADOME CONSTRUCTION DEFINING AN ELECTROMAGNETIC WINDOW FOR TRANSMITTING PRESELECTED MICROWAVE ELECTROMAGNETIC ENERGY. THE CONSTRUCTION IS DEFINED BY A WALL STRUCTURE HAVING AT LEAST THREE SPACED HIGH DIELECTRIC LAYERS, A LOW DIELECTRIC LAYER BETWEEN EACH PAIR OF HIGH DIELECTRIC LAYERS, AND A PLURALITY OF PARALLEL ELECTRICAL CONDUCTORS IN THE HIGH DIELECTRIC LAYERS. THE WALL STRUCTURE IS ARRANGED TO PROVIDE HIGH TRANSMISSION EFFICIENCY OVER A WIDE RANGE OF INCIDENCE ANGLES, LOW REFLECTION OVER A WIDE RANGE OF INCIDENCE ANGLES, AND LOW PHASE DELAY VARIATION OVER A WIDE RANGE OF INCIDENCE ANGLES.

Electronic scanning antenna systems

Abstract: 1,171,938. Aerials. THOMSON CSF. 9 Dec., 1966 [13 Dec., 1965], No. 55353/66. Heading H4A. In an antenna radiation lobe scanning system for monopulse radar, the antenna is formed of an array of elementary antennµ, or radiating sources, Sm, each of which has a phase adjuster, 1.m, in the associated feeder. The signal representing the required beam axis angle is applied at 30 to the phase computer, 30, which derives the theoretical value of the phase shift for each phase adjuster. The outputs from 30 are applied to the computer, 4, which derives quantized phase shift values, which approximate to the theoretical values, in accordance with a predetermined rounding-off law. The quantization phase errors, derived at 4, are applied to the computer, 5, together with the required angle signal, from 30, the beam angle error is provided at the output 52 but applied to the adder 7. The output from 7 is the effective beam angle and is applied to the data processor, 8, also fed from the receiver, 2.

Plural antennas with impedance matching to couple to single leadin

Abstract: An antenna array including a narrow band antenna tuned to a particular frequency and a transmission line type broadband antenna having a frequency response range which includes the frequency of the narrowband antenna. The transmission line of the broadband antenna is serially coupled between the narrowband antenna and reception apparatus. A parasitic element of a predetermined length is positioned at a predetermined point along the transmission line of the broadband antenna and serves to peak the frequency of the narrowband antenna thereby to pass signals from the narrowband antenna to the reception apparatus with minimum attenuation.

Combined television stand and antenna system

Abstract: A combination stand or table and antenna system for television receivers, in which the legs of the stand are used as antenna segments. Two legs at opposite corners of the stand are used together to form one dipole antenna, and another pair of legs is used to form a second dipole antenna. A circuit is provided for varying the proportion of the signal which is delivered from each antenna to the receiver, thus effectively rotating the antenna system for best signal reception.

The transient response of the coaxial cone antenna

Abstract: A coaxial cone antenna whose aperture is in the plane of a ground plane has been described theoretically and experimentally in the time domain. Its response to an incident step along the ground plane is essentially a pulse whose width is equal to the diameter of the outer conductor at the aperture. Limitations on the cone dimensions are also discussed.

Radar system for three-dimensional target position indication

Abstract: A radar system for three-dimensional target position indication, comprising on the one hand an antenna radiating a beam, wide in elevation, and on the other hand a frequency-dependent antenna radiating a pencil beam. The scanning plane of the second antenna is substantially coplanar to the beam plane of the first antenna. Furthermore, the system is provided with a device, which in response to given target signals received by means of the first antenna releases the transmitter of the second antenna to perform a scan during each pulse transmitted in the beam plane of said first antenna.

Selectively polarized antenna employing impedance matched crossed dipoles

Abstract: A selectively polarized antenna has an antenna element parallel to one axis, has a second antenna element parallel to an angularly displaced second axis, has a selector switch connected to the down lead, has a transmission line extending from the selector switch to a position adjacent the first antenna element, has an impedance-matching means connecting said transmission line to the first antenna element at points on opposite sides of the mid-point of that antenna element, has a second transmission line extending from the selector switch to a position adjacent the second antenna element, and has an impedance-matching means connecting the second transmission line to the second antenna element at points on opposite sides of the mid-point of that antenna element.

Input impedance and radiation efficiency of a center-fed dipole antenna with feed points displaced transverse to dipole axis

Abstract: A generalized analysis of a center-fed dipole antenna with feed points displaced transverse to the dipole axis is presented. Mathematical expressions for the near-zone field radiation are developed from which the input impedance integral is obtained. The theoretical investigation of the radiation efficiency of the same antenna is also made.

Surface wave antenna with beam tilt angle compensation

Abstract: A surface wave antenna for use on a finite asymmetric ground plane of length G in the propagation direction in which an endfired antenna projects an electromagnetic beam of wavelength lambda polarized in the elevation plane and whose tilt angle varies inversely as G/ lambda . A correcting dielectric film is mounted on the ground plane in front of the end-fired antenna for increasing the antenna length in the propagation direction.

Les-6 antenna system

Abstract: : The antenna system for a sixth experimental satellite (LES-6) is described. It is the first circularly polarized, despun, VHF antenna to be successfully used on an orbiting satellite. A relatively high-gain (11-db peak) beam is electronically scanned to be always Earth-directed. The evolution from the simple LES-5 antenna system is detailed, and performance characteristics of the flight configuration are given.

Antenna array beam scanning system

Abstract: An antenna array beam scanning system in which the antenna system beam pointing positions are scanned by providing a typical discriminator response for targets located at different angles to a given phase front alignment. The discriminator output is used to progressively phase the antenna array through step recovery diode local oscillators by using the discriminator output as a DC bias to linearly phase shift the step recovery diode local oscillators and make the antenna array beam track a target.

Periodically modulated dielectrically filled waveguide as a microwave antenna

Abstract: Complex solutions to a determinantal equation have been found numerically and employed to predict the properties of a frequency-scanning forward-radiating antenna obtained through a superposition of two waves propagating in oblique angles on an infinite periodic structure. The range of parameters of a usable antenna has been examined.