Showing papers on "Phased array published in 1969"
Patent•
16 Oct 1969
TL;DR: In this paper, a cylindrical antenna array system with two subarrays flush mounted on a conducting cylinder is described, 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 phases ON in a rotating manner to scan throughout 360* around the cylinder axis.
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
170 citations
TL;DR: The modified residue-calculus technique (MRCT) described in a companion paper may be combined with scattering matrix, multiple-reflection techniques to provide solutions in scattering matrix form to thick-wall waveguide phased array, modulated surface, and strip grating geometries as mentioned in this paper.
Abstract: The modified residue-calculus technique (MRCT) described in a companion paper may be combined with scattering matrix, multiple-reflection techniques to provide solutions in scattering matrix form to thick-wall waveguide phased array, modulated surface, and strip grating geometries. Each of these geometries may be regarded as a periodic array of thin plates modified by dielectric fillings, waveguide steps, and terminations. Solutions to the modified geometries are found by combining the exact solution to the thin-wall array problem with approximate solutions to certain waveguide discontinuity problems found by the MRCT. In particular, a value of the dominant mode reflection coefficient versus scan angle for the thick-wall array may be found accurate to two or three significant figures without need for matrix inversion. In general, reduction of matrix size by a factor of 5 or more over conventional methods with equivalent accuracy may be realized.
26 citations
01 Jan 1969
TL;DR: In this paper, a phase array of open-end rectangular waveguides is shown in Fig. 1 and the aperture fields, from which the radiation pattern may be calculated, and the reflection coefficient in each waveguide as a function of scan angle.
Abstract: URRENT applications in radio astronomy and radar have generated great interest in electronically scanned or phased array antennas. One such antenna is the phased array of open-end rectangular waveguides, a segment of which is shown in Fig. 1. An essential consideration in design of such antennas is that of matching the antenna over a wide range of scan angles to maximize power transfer from antenna to the space region. Thus, in the analysis of these arrays, the essential properties to be determined are the aperture fields, from which the radiation pattern may be calculated, and the reflection coefficient in each waveguide as a function of scan angle.
23 citations
Patent•
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14 Oct 1969
TL;DR: In this article, a phased array antenna device including a plurality of equally spaced antenna elements which are connected to a source of antenna power is used to adjust the radiation characteristics of the antennas by varying the phase and amplitude of the antenna currents in a predetermined manner.
Abstract: A phased array antenna device including a plurality of equally spaced antenna elements which are connected to a source of antenna power, and a plurality of impedance transforming four terminal networks capable of electrically adjusting the radiation characteristics of the antennas by varying the phase and amplitude of the antenna currents in a predetermined manner.
10 citations
Patent•
31 Jul 1969TL;DR: An antenna radiation pattern-measuring system and method for permitting measurement of a selected parameter of a pattern to be measured without requiring the use of a standard target or a remotely located receiver is described in this paper.
Abstract: An antenna radiation pattern-measuring system and method for permitting measurement of a selected parameter of a pattern to be measured without requiring the use of a standard target or a remotely located receiver. According to the invention, the beam from an optically fed phased array is periodically focused on a sensor, which may be the feed horn of the antenna, so that substantially all of the energy radiated in the test beam or beams from the array is utilized to measure the selected parameter.
9 citations
Patent•
06 Aug 1969TL;DR: In this article, a phased array consisting of two radiating faces back-to-back with time shared solid-state transmit circuits disposed therein between for enabling each of the faces in a high-duty cycle operating mode to optimize utilization of the transmit circuits.
Abstract: A phased array consisting of two radiating faces back-to-back with time shared solid-state transmit circuits disposed thereinbetween for enabling each of the radiating faces in a high-duty cycle operating mode to optimize utilization of the solid-state capabilities of the transmit circuits.
9 citations
TL;DR: In this paper, 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, which operates at 3200 GHz.
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
7 citations
Patent•
31 Dec 1969
TL;DR: In this paper, a phased array antenna is grouped and signals from the various groups are combined to produce an elevation difference signal and an azimuth difference signal, which are then combined to generate a roll stabilization signal.
Abstract: Elements of a phased array antenna are grouped and signals from the various groups are combined to produce an elevation difference signal and an azimuth difference signal. The elevation difference passes through circuitry having a control signal that varies with the cosine of the antenna roll angle and the azimuth difference signal passes through a circuit having a control input equal to the sine of the roll angle. The outputs of each of these circuits are combined to produce a roll stabilization signal.
7 citations
01 Jan 1969
4 citations
Patent•
08 Sep 1969
TL;DR: In this paper, a series capacitance or shunt inductance is placed in the transmission path formed by the ground plane and free space in order to increase the phase velocity of any TM wave that might propagate along the ground planes so that it is at least equal to the phase velocities of a free space wave.
Abstract: A phased array antenna consisting of a plurality of radiating elements associated with a ground plane and including a reactive impedance for reducing the catastrophic effect produced by endfire grating lobes and surface waves. A series capacitance or shunt inductance is placed in the transmission path formed by the ground plane and free space in order to increase the phase velocity of any TM wave that might propagate along the ground plane so that it is at least equal to the phase velocity of a free space wave.
TL;DR: In order to restrict grating lobes from real space with fewer radiating elements, the triangular rather than rectangular radiating element arrangement is frequently selected in this article, where the price is the admission to real space of grating-lobe quantization sidelobes.
Abstract: In order to be able to restrict grating lobes from real space with fewer radiating elements, the triangular rather than rectangular radiating element arrangement is frequently selected. The price is the admission to real space of grating-lobe quantization sidelobes.
Patent•
08 Jul 1969TL;DR: In this paper, a beam-steering apparatus in combination with a phased array antenna is described, which comprises a source of reference pulses of frequency (1/T0) and a means responsive to beamsteering angle magnitude signals phi for generating proportional pulse width modulated pulses such that each pulse width T phi T 0/2 pi.
Abstract: A beam-steering apparatus in combination with a phased array antenna. The apparatus comprises a source of reference pulses of frequency (1/T0). Also included are means responsive to beamsteering angle magnitude signals phi for generating proportional pulse width modulated pulses such that each pulse width T phi T0/2 pi . Additional means responsive to the modulated pulses alter the phase of the corresponding phase shift device in the phased array element with output pulses of width T when (T/T0) 1, and T- T0 when (T/T0)>1.
03 Nov 1969
TL;DR: In this paper, an optimal spatial distribution of aperture for enhancing array reception is developed for three types of noise fields and for both spatially constrained and spatially unconstrained array element geometry.
Abstract: : This research analytically develops an optimal spatial distribution of aperture for enhancing array reception. The optimization is carried out for three types of noise fields and for both spatially constrained and spatially unconstrained array element geometry. The noise fields considered are those due to (1) noise sources uniformly distributed in a volume around the array (isotropic noise), (2) noise sources uniformly distributed on an unbounded plane, and, (3) directive noise fields such as due to a point source. The optimality criterion employed is minimization of the detection error probability for the array situation. For a phased array this is equivalent to maximization of the array detectability gain function which has the effect of maximizing the predetection signal-to-noise ratio. Situations under which such a criterion is valid are discussed and the associated time-optimal receiver structures for these situations are given. (Author)
TL;DR: In this paper, the effect of an anisotropic reverberation pattern on the performance of various signal processing systems for linear sonar arrays was studied. And it was determined that the use of clipping at each array element could seriously affect the system in comparison on to a similar analog system.
Abstract: The effect of an anisotropic reverberation pattern on the performance of various signal processing systems for linear sonar arrays was studied. It was determined that the use of clipping at each array element could seriously affect the performance of the system in comparison on to a similar analog system.
10 Mar 1969
TL;DR: In this paper, a maximum likelihood array receiver is analyzed and a performance index (the array detectability) for the receiver is developed and related to the system parameters, array dimensionality and geometry, and to the space-time correlation properties of the incident interference field.
Abstract: : This report examines the problem of optimizing the detectability of array receiving systems. A 'maximum likelihood' array receiver is analyzed and a performance index (the array detectability) for the receiver is developed and related to the system parameters, array dimensionality and geometry, and to the space-time correlation properties of the incident interference field. A sensitivity analysis of system performance (array gain) to a priori information error in signal phasing (steering angle) is performed and a number of case studies of detectability optimization are examined for various array coupling geometries, and various interference spatial correlation models. (Author)
05 May 1969
TL;DR: In this article, the use of injection phase locked Gunn effect oscillators as module transmitters for distributed phased array applications is described, which are capable of direct dc to microwave conversion with reasonable efficiencies and useful power levels.
Abstract: This paper describes the use of injection phase locked Gunn effect oscillators as module transmitters for distributed phased array applications. These devices are capable of direct dc to microwave conversion with reasonable efficiencies and useful power levels. However, certain problem areas must be investigated before they can be successfully employed. These areas include peak and average power output, sensitivity of output power and frequency to the microwave circuit and bias voltage, phase control, reproducibility and cost, driver requirements, and temperature and frequency stability.
Patent•
14 Apr 1969
TL;DR: In this article, an impedance-matched phased array antenna with a plurality of impedance-matching members, each consisting either of a thin sheet of high-k dielectric material or thin metal pieces which collectively have dielectrical characteristics at the operating wavelengths, is described.
Abstract: An impedance-matched phased array antenna in which the radiating elements comprise slots or holes in a conductive ground plane. The antenna includes a plurality of impedance-matching members, each consisting either of a thin sheet of high-k dielectric material or thin metal pieces which collectively have dielectric characteristics at the operating wavelengths. Each impedance matching member is supported in laterally spaced relationship with the other impedance matching members by a dielectric support member associated with each opening in the ground plane. Each combination of impedance-matching member and support member provides environmental protection for one of the openings in the ground plane. The lateral spacing between the impedance-matching members prevents accumulation of large sheets of water in front of the radiating elements which could cause severe impedance mismatches. Alternative arrangements are also covered.
01 Jan 1969
TL;DR: In this paper, it was shown that the phase array must possess certain symmetry properties for the complex-symmetric form of the integral equation for infinite-phased arrays to exist.
Abstract: The integral equations for infinite phased arrays have generally been constructed with complex nonsymmetric kernels. Nevertheless, it has been shown earlier that these nonsymmetric forms can generally be transformed into a complex-symmetric form with consequent stationary properties. It is shown here that the phased array must possess certain symmetry properties for the complex-symmetric form to exist.
TL;DR: Ideas of spacecratt phased array configurations are described in this communication and the aperture of the phased array is 28.5 by 28.
Abstract: Ideas of spacecratt phased array configurations are described in this communication. The aperture of the phased array is 28.5 by 28.5 feet.
01 Dec 1969
TL;DR: In this paper, a two-element adaptively phased array with gain improvement of 18 dB was assembled and evaluated at 136 MHz and the measured gain improvement fell within 0.5 dB of the theoretical maximum 90 percent of the time.
Abstract: A two-element adaptively phased array withelement gains of 18 dB was assembled andevaluated at 136 MHz. The gain improvementof the system over that of a single element wasmeasured while tracking ATS-C. The measuredgain improvement fell within 0.5 dB ofthe theoretical maximum 90 percent of thetime, corresponding to a normalized improvementof 2.5 dB for the two-element array. Athorough analysis of the AGC weighting processused in the system was made with particularemphasis placed on the effects of gainand noise figure variations between arraychannels.