Phased array

About: Phased array is a research topic. Over the lifetime, 19428 publications have been published within this topic receiving 229231 citations. The topic is also known as: Phased Array Radar, PAR.

Adaptive nulling hyperthermia array

Abstract: A hyperthermia array uses adaptive nulling with non-invasive auxiliary probes to reduce the electric field intensity at selected positions in the target body while maintaining a desired focus at a tumor thereby avoiding or reducing the occurrences of "hot spots" during ultrasonic or R.F. hyperthermia treatment. A hyperthermia applicator has an annular phased array of electric field radiators coupled to a source of electric radiation through a controllable transmit weighting network to control the phase and amplitude of the electric field radiation transmitted. The transmit weighting networks respond to feedback signals from a controller coupled to ele GOVERNMENT SUPPORT The invention described herein was supported in whole or in part by Contract No. F19628-90-C-0002 from the United States Air Force.

Flat phased array antenna

Abstract: A flat phased array antenna (10) for reception of circularly polarized high frequency signals. The flat antenna array consists of a number of subarrays (12) arranged in a matrix. In turn, each of the subarrays consist of individual antenna elements (22) arranged in a matrix. In one embodiment, each subarray consists of four layers (14, 16, 18, 20) stacked one on top of the other. The top layer (14) defines an array of miniature reception horns. Secured to the top layer is a second layer (16) which constitutes the short-circuit plate of the antenna array. The short-circuit plate contains a plurality of through holes (44) disposed about the surface of the circuit plate to permit passage of pairs of cylindrically shaped probes (46). The two remaining layers constitute the first power dividing layer (18) and the second power dividing layer (20), respectively. Each of the layers includes transmission line waveguides (56). The complete interior surface of the waveguides is coated with a metallic film and contains a number of spaced non-conductive supports (62, 82) for supporting a metallic conductor at the central location of the waveguide when the channel (60, 80) is viewed in cross-section. This arrangement creates a rectangular coaxial transmission line with the conductor forming the central conductor and the metallically coated channel forming the outer conductor. At the end of certain channels are the vertically extending, cylindrically shaped non-conductive probes (70, 80). In a second embodiment, non-conductive strips (201) with spaced supports (211) carry the metallic conductor (66). The probes (46) are intregrally formed as part of the non-conductive strips. In still another embodiment, the probes of the first embodiment are replaced by conductive legs (323, 337) formed in the same plane as the metallic conductor. In addition, the two channels (313, 327) are formed along both sides of a single layer (318) and recessed into that layer.

Time-multiplexed phased-array antenna beam switching system

Abstract: An optical control system for a phased-array antenna system employs a time-multiplexed optical control architecture to provide very fast (a few hundred beams per second) antenna beam scanning using slow (milliseconds) response spatial light modulators in two optical signal processing channels. In each channel a cascade of relatively slow switching speed nematic liquid crystal cell spatial light modulators and associated free space delay units or fiber optic delay cables are disposed to receive transmit or receive optical input signals comprising a plurality of light beams. The control voltages applied to the spatial light modulators determine the paths of the light beams through the cascade and the differential time delay imparted to the light beams in the input optical signal. High speed 90° polarization rotators control the polarization of the transmit and receive optical input signals and the polarization of optical signals passing from the cascade, allowing for selecting the active channel and the transmit or receive mode of the active channel, thus enabling sequential rapid beam scans of the radar with a relatively short dead time between respective transmit/receive sequences. The spatial light modulators in the non-active channel are reconfigured during the dwell time of the active channel to set up for the next transmit/receive sequence.

Ultrasonic phased array imaging system with high speed adaptive processing using selected elements

Abstract: Disclosed is an ultrasonic phased array imaging system which includes a normal mode and an adaptive mode of operation The adaptive mode adjusts the delay associated with each element in the transducer such that the average image brightness of the region of interest is maximized Also disclosed is a method of correcting for phase aberration using selected elements of an ultrasonic array specific to each element of the array to correct each element of the array It is further disclosed that the use of corrected elements to correct subsequent elements in the array results in more accurate phase aberration correction In a preferred embodiment, the determination of the maximum average image brightness is performed more accurately through the use of selectable transducer array elements and previously corrected data during adaptive processing

Circuit module for a phased array radar

Abstract: A circuit module for a phased array radar (10) incorporates radar frequency (RF) mixers (54a, 54b) connected to an RF splitter/combiner (52) and to in-phase and quadrature RF reference signals. The RF mixers (54a, 54b) are also connected to intermediate frequency (IF) processing circuitry (60 to 68) providing for phase control of RF signals and IF reference signals. In transmission mode, the RF mixer (54a, 54b) receive phase-controlled, digitally synthesised IF signals from clock-activated generators (68a, 68b). Their outputs are combined at the RF splitter/combiner (52) to provide single sideband upconversion of the phase-controlled IF signals. In reception mode, the RF splitter/combiner (52) and the RF mixers (54a, 54b) act as an image rejection mixer circuit in which the phase-controlled IF signals are local oscillator signals. Beamforming is carried out by computer control of the IF phase together with, in the case of reception, analogue or digital summation of output signals from an array of modules (12).