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.

Wide-Angle Scanning Phased Array With Pattern Reconfigurable Elements

Abstract: A novel phased array is presented to extend array scanning range by using pattern reconfigurable antenna elements and weighted thinned synthesis technology in this paper. The pattern reconfigurable microstrip Yagi antenna element is used as a basic element in array and it is capable of reconfiguring its patterns from broadside to quasi-endfire radiation by shifting states of the PIN diode switches integrated on parasitic strips. A weighted thinned linear array synthesis technique is analyzed and some interesting conclusions have been made. A linear array composed of eight pattern reconfigurable antenna elements is manufactured to demonstrate the excellent performance of the array. The active element pattern of each element is measured and pre-stored. Based on active element patterns and weighted thinned linear array synthesis technique, the pattern scanning performance of the novel array is synthesized. The results indicate that the array can scan its main beam from φ = -60° to φ = 60° in H-plane with gain fluctuation less than 3 dB while maintaining low side lobes, and the -3 dB beam width coverage is about from φ = -68° to φ = 68°. The performance is superior to the traditional phased array made of wide-beam elements.

Phased array antenna with temperature compensating capability

Abstract: Generally, a variation of temperature at the installation site causes a phased array antenna radiation pattern to degrade. This paper describes the temperature characteristics of various components of the phased array antenna and degradations of the radiation pattern originating from temperature variations. It is effective to measure the phase distribution on the aperture and correct it, as the occasion demands, to prevent such degradations. Also, we propose a simple and effective algorithm for the measurement of the current distribution on the aperture, and present the evaluation test results of a phased array antenna with temperature compensation obtained by applying the algorithm.

Phased array theory and technology

Abstract: This review of array antennas highlights those elements of theory and hardware that are a part of the present rapid technological growth. The growth and change in array antennas include increased emphasis on "special-purpose" array techniques such as conformal and printed circuit arrays, wide angle scanning arrays, techniques for limited sector coverage, and antennas with dramatically increased pattern control features such as low sidelobe, adaptively controlled patterns. These new topics have substantially replaced large radar arrays in the literature and constitute a major change in the technology. The paper presents a tutorial review of theoretical developments emphasizing techniques appropriate to finite arrays, but indicating parallel developments in infinite array theory, which has become the useful tool for analysis of large arrays. A brief review of the theory of ideal arrays is followed by a generalized formulation of array theory including mutual coupling effects, and is appropriate to finite or infinite arrays of arbitrary wire elements or apertures in the presence of a conducting ground screen. Some results of array tolerance theory are summarized from the literature and retained as reference throughout discussions of array component requirements and device tolerance for low sidelobe arrays. Examples from present technology include conformal and hemispherical coverage arrays, lightweight printed circuit arrays, systems for use with reflectors and lenses in limited sector coverage applications, and wide-band array techniques.

The Long Wavelength Array

Abstract: The Long Wavelength Array (LWA) will be a new multipurpose radio telescope operating in the frequency range 10-88 MHz. Upon completion, the LWA will consist of 53 phased array ldquostationsrdquo distributed over a region about 400 km in diameter in the state of New Mexico. Each station will consist of 256 pairs of dipole-type antennas whose signals are formed into beams, with outputs transported to a central location for high-resolution aperture synthesis imaging. The resulting image sensitivity is estimated to be a few millijanskys (5 sigma, 8 MHz, two polarizations, 1 h, zenith) in 20-80 MHz; with resolution and field of view of (8 '', 8deg) and (2'', 2 deg) at 20 and 80 MHz, respectively. Notable engineering features of the instrument, demonstrated in this paper, include Galactic-noise limited active antennas and direct sampling digitization of the entire tuning range. This paper also summarizes the LWA science goals, specifications, and analysis leading to top-level design decisions.

Low cost polarization twist space-fed E-scan planar phased array antenna

Abstract: A polarization twist, space-fed, E-scan planar phased array antenna. The phased array antenna incorporates a polarization twist, space-fed architecture. A plurality of unit cells are formed wherein each cell incorporates a large plurality of phased array elements and associated phase shifters. The space-feed architecture enables 2-bit phase shifters to be employed while still producing low antenna sidelobes. The phased array elements, phase shifters, and associated control circuits for controlling the phase shifters are all preferably formed on one surface of a MMIC substrate. This further simplifies significantly the cost and complexity of manufacturing and testing the E-scan phased array antenna. The antenna can therefore be used in applications where an E-scan phased array antenna would have been too costly to employ. The antenna of the present invention is expected to find particular utility in various radar systems, and more particularly missile defense radar systems where E-scan antennas have traditionally been too expensive to employ.