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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03 Mar 2007
TL;DR: In this paper, the effects of deformations and vibrations on the performance of array antennas are discussed, and a technique to counteract these effects by means of adaptive or synthetic beam forming is described.
Abstract: Array antennas which are integrated onto structures of aircraft and unmanned aerial vehicles (UAVs) are subject to unsteady aerodynamic loads. Mechanical forces and these aerodynamic loads will cause deformation of the antenna supporting structure. As a consequence, the positions and orientations of the elements of the phased array antenna change. The relative phases of the respective signals feeding the antennas will vary, and as a consequence the antenna radiation pattern is affected: the main beam direction can change and the beam width and/or side lobe levels can increase. The influence of deformations and vibrations will be most significant on array antennas, which are large in terms of wavelength (high gain antennas). The objective of the present paper is to present some applications of such array antennas, and to discuss the effects of deformations and vibrations on the performance of array antennas, and to describe technology to counteract these effects by means of adaptive or synthetic beam forming.
65 citations
TL;DR: The results show that the guided wave phased array method is a potential effective method for rapid inspection of large composite structures and provides intrinsic explanations for phased array beamforming.
65 citations
TL;DR: In this article, a four-element fiber array was constructed to yield 8 watts of coherently phased, linearly polarized light energy in a single far field spot, where each element consists of a 2-W single-mode fiber-amplifier chain.
Abstract: A four-element fiber array has been constructed to yield 8 watts of coherently phased, linearly polarized light energy in a single far field spot. Each element consists of a 2-W single-mode fiber-amplifier chain. Phase control of each element is achieved with a lithium-niobate phase modulator. A master laser provides a linearly polarized, narrow linewidth signal that is split into five channels. Four channels are individually amplified using polarization maintaining fiber power amplifiers. Frequency broadening of the signal is necessary to avoid stimulated Brillouin scattering. The fifth channel is used as a reference arm. It is frequency shifted and then combined interferometrically with a portion of each channel's signal. Detectors sense the heterodyne modulation signal, and an electronics circuit measures the relative phase for each channel. Compensating adjustments are then made to each channel's phase modulator. The stability of the optical train is an essential contributor to its success. A state-of-the-art interferometer was built with mountless optics. A lens array was constructed using nano-positioning tolerances, where each lens was individually aligned to its respective fiber to collimate its output and point it at a common far field spot. This system proved to be highly robust and handled any acoustic perturbations.
64 citations
IBM1
TL;DR: In this paper, a multi-function, dual-polarization phased array transceiver supporting both radar and communication applications at W-band is presented, which includes two independent 16:1 combining networks, two receiver downconversion chains, an up-conversion chain, a 40GHz PLL, an 80GHz frequency doubler, extensive digital control circuitry, and on-chip IF/LO combining/distribution circuitry to enable scalability to arrays at the board level.
Abstract: This paper presents a multi-function, dual-polarization phased array transceiver supporting both radar and communication applications at W-band. 32 receive elements and 16 transmit elements with dual outputs are integrated to support 16 dual polarized antennas in a package. The IC further includes two independent 16:1 combining networks, two receiver downconversion chains, an up-conversion chain, a 40GHz PLL, an 80GHz frequency doubler, extensive digital control circuitry, and on-chip IF/LO combining/distribution circuitry to enable scalability to arrays at the board level. The fully-integrated transceiver is fabricated in the IBM SiGe BiCMOS 0.13um process, occupies an area of 6.6×6.7mm2, and operates from 2.7V (analog/RF) and 1.5V (digital) supplies. Multiple operating modes are supported including the simultaneous reception of two polarizations with a 10GHz IF output, transmission in either polarization from an IF input, or single-polarization transmission/reception from/to I&Q base-band signals (2.5W RX, 2.9W TX). Measurement results show 8dB receiver NF and 2dBm transmitter output power per element at 94GHz in both polarizations.
64 citations
TL;DR: In this article, the antenna properties of different plasma structures of a plasma column as a reconfigurable plasma antenna were investigated, and the effect on directivity with the number of antenna elements was also studied.
Abstract: An experiment aimed at investigating the antenna properties of different plasma structures of a plasma column as a reconfigurable plasma antenna, is reported. A 30 cm long plasma column is excited by surface wave, which acts as a plasma antenna. By changing the operating parameters, e.g., working pressure, drive frequency, input power, radius of glass tube, length of plasma column, and argon gas, single plasma antenna (plasma column) can be transformed to multiple small antenna elements (plasma blobs). It is also reported that number, length, and separation between two antenna elements can be controlled by operating parameters. Moreover, experiments are also carried out to study current profile, potential profile, conductivity profile, phase relations, radiation power patterns, etc. of the antenna elements. The effect on directivity with the number of antenna elements is also studied. Findings of the study indicate that entire structure of antenna elements can be treated as a phased array broadside vertic...
64 citations