Showing papers on "Antenna array published in 1969"

Scanned cylindrical array monopulse antenna

Abstract: A cylindrical antenna array system having two cylindrical subarrays flush mounted on a conducting cylinder, each consisting of a plurality of linear phased arrays fed through a pair of feed rings on the conducting cylinder that has a diode switch for each linear phased array coupled through a switching network to switch one-quarter to one-third of the linear phased arrays ON in a rotating manner to scan throughout 360* around the cylinder axis, and each linear phased array having a pair of rotatable dielectric slabs behind the waveguide slots thereof with all dielectric slabs mechanically coupled to rotate in synchronism to phase the radio waves for angular direction with respect to the cylinder axis, the received signals being coupled through a magic-T junction to provide sum and difference monopulse signals of targets in sight of the antenna

Combined dipole and waveguide radiator for phased antenna array

Abstract: An antenna includes a waveguide slot aperture radiator and a dipole radiator centrally located therein and located longitudedly with respect to the waveguide a quarter wavelength from the aperture. Each radiator is separately excited.

Antenna array phase quadrature tracking system

Abstract: The system input signals on two separate antenna elements in an antenna array are combined to form two processed signals with one such signal representing the absolute value of the sum of the two antenna signals and the other representing the absolute value of the difference of the signals. The two processed signals are time multiplexed through a radiofrequency switch operating at 10millisecond intervals to form a single input signal to a receiver which in turn detects amplitude modulation in the multiplexed signal and forms an amplitude dependent signal to control a variable phase shifter circuit. The latter circuit automatically alters the relative phase between the two antenna signals whenever any amplitude modulation exists in the multiplex signal. Relative phase shift of the antenna signals stops when the absolute value of the two processed output signals are equal to each other which occurs only when the two antenna signals are in phase quadrature. The described procedure may be employed for any number of antennas connected in parallel to provide substantially omnidirectional antenna coverage and the time multiplexing and signal processing operations may be performed with stripline circuitry and techniques. For transmitting, a phase detector is employed to detect the phase modulation in the received multiplexed signal to establish and switch to the antenna in the array which will provide the greatest system gain for use while transmitting. The invention described herein was made by an employee of the United States Government and may be manufactured and used by or for the government for governmental purposes without the payment of any royalties thereon or therefor.

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.

A data-gathering antenna array for transhorizon propagation research

Abstract: A versatile vertical antenna array and receiving system have been developed for measuring relative phase and amplitude along the wavefront of an S -band transhorizon signal The array, which operates at 3200 GHz, consists of 12 parabolic antennas 122 meters (4 feet) in diameter which are spaced 139 meters apart on a tower for a total effective vertical aperture of 1524 meters ( 162 \lambda ) The raw data outputs from the array are amplitude and differential phase successively sampled from the 12 elements Data can be taken at variable rates of up to 100 passes per second over the 12 elements The data are processed in a computer to form conventional uniformly illuminated array beams 03 degree wide with a grating lobe spacing of 39 degrees or to produce many combinations of correlation functions A reference signal is used to cancel the effects of relative motion of the array support structure from the phase data The array and receiving system and actual performance characteristics are described

Redirective and retrodirective antenna arrays

Abstract: The problem considered is the redirection of a time-varying signal from one specified point to another by a set of arbitrarily spaced antenna array elements. The necessary and sufficient condition for signal redirection is determined without restricting the analysis to a monochromatic signal. This condition, which involves time delays only, is valid for signal redirection in general and hence, in particular, for retrodirection. Once the condition for redirection is satisfied, the amplitude of the signal retransmitted from each array element can be chosen at will Proper adjustment of these amplitudes will maximize the amplitude of the redirected signal as received at the specified point. The appropriate criterion for maximization is derived. In addition, the problem of noise (undesired signal) generation due to errors in the time delays is considered.

Control circuit for setting phase shifters in scanned antenna array

Abstract: According to the present disclosure, apparatus and process is provided for controlling delay devices in antenna elements of antenna arrays for controlling the direction of propagation of electromagnetic radiation. An analog signal is developed from a digital signal and operates on a first control device in a predetermined manner. The analog signal is subsequently altered, as by altering the digital signal in a binary adder, and the altered analog signal operates on the next control device. The control devices are arranged in sequential relation and are successively operated by a clock.

Apparatus and method of compensating a long highly dispersive traveling wave transmission line

Abstract: A method and structure for correcting and linearizing the phase distribution along the waveguide transmission line feed of a long, highly dispersive, slow-wave, N-element antenna array. The method involves the phase probing of the individual radiating elements of a linear array formed by slotting a serpentine waveguide feed. This probing is carried out in predetermined equal increments of Y-elements each. The measured phase over each of the increments of Y-elements is subtracted from a theoretical or reference phase desired at the predetermined element and the phase error ( Delta phi ) thus determined is divided by Y. Individual dielectric panels are affixed to the serpentine broad internal walls (''''a'''' dimension walls). Enough panels are inserted between the radiators of each adjacent pair to provide a - Delta phi /Y phase shift. The process is repeated N/Y times for each linear array. A twodimensional array can be assembled from M of these linear arrays, with each linear array having equal phase distribution characteristics overall and among its N-elements.

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.

Miniaturized ferrite phase shifters for electronically steered antenna arrays

Abstract: DESCRIBED ARE MINIATURIZED ANALOG X-BAND MICROSTRIP FERRITE PHASE SHIFTERS PARTICULARLY ADAPTED FOR USE IN AIRBORNE ANTENNA ARRAYS. ALSO DESCRIBED IS A NOVEL ANTENNA ARRAY ASSEMBLY ITSELF. THE ELEMENTS CONTAINING THE PHASE SHIFTERS ARE DESIGNED INTO HALF-WAVELENGTH SPACING TO ACHIEVE A TWO-AXIS SCAN AND COMPRISE MICROSTRIP TRANSMISSION LINES DEPOSITED ON THIN FERRITE FILMS SURROUNDED BY SUITABLE ACTUATING COILS.

Microwave antenna having an undulating conductor with variable pitch and amplitude

Abstract: The antenna array disclosed comprises an undulatory conductor which is capable of transmission and reception of energy, in which the amplitude and pitch of the undulations are progressively altered along the array to produce an array having directional characteristics, and a main lobe to side lobe ratio, which are those of a Dolph-Tchebycheff array. The undulations are circularly arcuate and blended into one another and the conductor is etched from one copper layer of a strip of low loss copper clad laminate, the other layer of which forms a ground plane.

Method of and device for aiming barrels of cannons installed in terrain from a remote aiming station

Abstract: A method of and an apparatus for the training of pieces of artillery on to a target from a remote control station. At the control station is a transmitting antenna array for sending beat signals to a receiving antenna array at the piece of artillery to be trained. By measuring the phase shift of the signals received by the receiving array the angle between a base line at the control station and a reference line from the station to the artillery piece can be determined and from this a second base line at the artillery piece can be established for the purpose of laying the piece on to the target.

Strip line ferrite phase shifter

Abstract: Described is a small, lightweight ferrite phase shifter, constructed in a strip line wave energy transmission assemblage, which is small enough to fit into a steerable antenna array while at the same time providing good electrical isolation between adjacent phase shifters in the array.

Medium frequency ionospheric and meteor observations using a large antenna array.

Abstract: : An array of 100 dipoles is employed to study radio signals reflected and scattered from ionospheric irregularities and meteor trails in order to determine changes and drifts in ionospheric irregularities and wind gradients at high altitudes. (Author)