Topic
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.
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Patent•
27 Nov 1996
TL;DR: In this article, a phase shifter is mounted on a substrate in each active array module, with the substrate disposed in a position normal to the propagation of the EM signals in the corresponding waveguide of the antenna waveguide structure.
Abstract: A phased-array antenna structure is provided that includes an antenna waveguide structure (404) with a plurality of waveguides (406). The antenna waveguide structure propagates the received or transmitted electromagnetic (EM) signals within the plurality of waveguides to a corresponding active array module (408). Each active array module amplifies and adjusts the phase of a received or transmitted EM signal. The active array modules are coupled to an interconnect structure (416) that provides EM signal propagation paths, as well as power and digital signal paths, to and from the active array modules. A plate (420) is coupled to the interconnect structure and the antenna waveguide structure to support the antenna waveguide structure, the electronic modules, and the interconnect structure, thereby forming a rigid unit and keeping the electronic modules in alignment with their corresponding waveguides in the antenna waveguide structure. The plate also includes waveguides for propagating the EM signals from the interconnect structure to the antenna output. The active array modules each include an integrated polarizer for selectably operating with either right-hand circularly polarized signals or left-hand polarized signals. The polarizer, amplifiers and phase shifters are mounted on a substrate in each active array module, with the substrate disposed in a position normal to the propagation of the EM signals in the corresponding waveguide of the antenna waveguide structure, resulting in a planar configuration. Further, each active array module includes a waveguide as an integral part of the active array module.
94 citations
TL;DR: High spatial resolution two‐ or three‐dimensional chemical shift images of normal brain were obtained in 17‐minute acquisitions and coverage and SNR increases demonstrated are similar to those obtained in magnetic resonance phased array imaging.
Abstract: Two and four-coil phased array detectors have been developed to increase the sensitivity of proton spectroscopic imaging of the human brain. These include a quadrature figure-8 coil for the study of the vertex, several arrays of 2-4 small overlapping (6-8 cm diameter) circular coils and a combination figure-8 coil plus circular coil. These were constructed in our laboratory and tested to assess their utility for brain spectroscopy. Methods for optimally combining the data from the independent receivers based on the analytical coil maps or measured signal to noise ratios (SNRs) of the data were investigated. High spatial resolution (0.2-0.4 cm3 voxel size) two- or three-dimensional chemical shift images of normal brain were obtained in 17-minute acquisitions. These spatial resolutions are comparable to those previously obtained with conventional small surface coils, but the specialized detectors allow this sensitivity to be achieved for a larger region or for previously inaccessible areas such as the top of the head. The coverage and SNR increases demonstrated are similar to those obtained in magnetic resonance phased array imaging.
94 citations
Patent•
09 Apr 2001
TL;DR: In this paper, a transmit and receive module for active phased array antenna system based upon a combination of hybrid microwave integrated circuit (MIC) as well as monolithic microwave integrated circuits (MMIC) technology is presented.
Abstract: This invention relates to a transmit and receive module for active phased array antenna system based upon a combination of hybrid microwave integrated circuit (MIC) as well as monolithic microwave integrated circuit (MMIC) technology. The module comprises a signal transmit chain having switching means (03) for switching the module to transmittance mode. Means are provided for applying pulsed RF signal to the said module from array manifold. A phase shifter (01) is connected to a digital attenuator (02) and the output of the attenuator (02) is connected to a power amplifier (04). The amplified signals from amplifier (04) are conveyed to a duplexer means (05) connected to said power amplifier (04) and for routing back the received signal through a receiver protector (06) and low noise amplifier means (07). Electronic means are connected to a power conditioner for controlling the operation of the device.
93 citations
TL;DR: Simulations were performed to predict the performance and capabilities of various combined array designs by using numerical routines to, calculate the acoustic power field, temperature distribution, and accumulated thermal dose and predict that the combined array can create necrosed tissue volumes over 30 times larger than the concentric-ring array while maintaining focal range.
Abstract: MRI guided ultrasound surgery requires small surgical equipment volumes to facilitate the treatment of larger patients in the limited space of a conventional MRI magnet. In addition, large focal volumes are required to reduce the treatment time of large tumors. The concentric-ring array is capable of moving the focus in one dimension, and previous studies have shown that a circular array composed of radial sectors is capable of producing enlarged focal volumes. These two array designs may be combined to create an array that is capable of both enlarging the focus and moving the focus along the axis of the array. Simulations were performed to predict the performance and capabilities of various combined array designs by using numerical routines to, calculate the acoustic power field, temperature distribution, and accumulated thermal dose. The results shown predict that the combined array can create necrosed tissue volumes over 30 times larger than the concentric-ring array while maintaining focal range. The simulation results were verified with an experimental array consisting of 13 rings and 4 sectors. In addition, simulations were performed where multiple focal patterns were cycled in the time domain to create an optimized heating pattern characterized by uniform thermal dose over the volume of the lesion. Such heating patterns resulted in a 40/spl deg/C lower maximum temperature compared to single mode sonications while producing the same necrosed tissue volume, and yielded a rate of necrosis of 26.4 cm/sup 3//h.
93 citations
TL;DR: A new method for efficiently processing MRS data acquired with phased‐array coils is presented, which consists of performing phase compensation of the signals in the time domain before combining the signals.
Abstract: A new method for efficiently processing MRS data acquired with phased-array coils is presented. The method consists of performing phase compensation (i.e., redefining the signal phase relative to a common reference) of the signals in the time domain prior to combining the signals. The resulting spectra are equivalent to those obtained by previously published methods for phased-array spectral data processing (i.e., processing the signals individually and then combining them in the frequency domain). The method allows spectra acquired with phased-array coils to be processed as efficiently as those acquired with non-phased-array coils. Both single voxel spectroscopy (SVS) and chemical shift imaging (CSI) data sets may be processed by this method.
93 citations