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.

X-band RF MEMS phase shifters for phased array applications

Abstract: In this work, development of a low-loss radio frequency (RF) microelectromechanical (MEMS) 4-bit X-band monolithic phase shifter is presented. These microstrip circuits are fabricated on 0.021-in-thick high-resistivity silicon and are based on a reflection topology using 3-dB Lange couplers. The average insertion loss of the circuit is 1.4 dB with the return loss >11 dB at 8 GHz. To the best of our knowledge, this is a lowest reported loss for X-band phase shifter and promises to greatly reduce the cost of designing and building phase arrays.

Range-Angle Dependent Transmit Beampattern Synthesis for Linear Frequency Diverse Arrays

Abstract: Phased-array is widely used in communication and radar systems, but the beam steering is fixed in an angle for all the ranges. In this paper, we propose a range-angle dependent beampattern synthesis scheme for linear frequency diverse array (FDA) using the discrete spheroidal sequence, with an aim to focus the transmit energy in a desired two-dimensional spatial section. Different from conventional phased-arrays, FDA employs a small frequency increment, compared to the carrier frequency across the array elements. The range-angle dependent beampattern synthesis method allows the FDA to transmit energy over a desired range or angle sector. This provides a potential to suppress range-dependent clutter and interference, which is not accessible for conventional phased-arrays. The system performance of the proposed FDA is evaluated by the output signal-to-interference-plus-noise ratio (SINR). The effectiveness is verified by comprehensive numerical simulation results.

A relation between the active input impedance and the active element pattern of a phased array

Abstract: It is well known that the active element pattern of a phased array, obtained by driving a single radiating element of the array while all other elements are match terminated, can be expressed in terms of the scattering matrix parameters of the array. It is shown how this relationship can be inverted so that the scattering parameters for all elements of a phased array can be obtained from the active element patterns of the array. In addition, it is also possible to obtain the active input impedance of any element in the fully excited array, at any scan angle, from active element pattern data. The theory is developed for linear and planar arrays and an example is presented for a linear array of slot antenna elements.

Beam focusing behavior of linear phased arrays

Abstract: One of the fundamental features of phased arrays is the ability to focus the propagating waves to a specific point within the load material by inducing a parabolic time delay. This required focusing time delay has been modified from the current formulation to incorporate either an odd or even number of elements. A brief procedure leading to the derivation of the pressure distribution for beam focusing is described, which gives rise to an unclosed form. Consequently, a numerical method is desirable for the analysis of beam focusing. Using this approach, beam directivity and pressure distributions are studied to predict the behavior of focusing as compared to steering. This shows a benefit of focusing over steering within the near field of the array, and that the directivity of focusing converges to that of steering in the far field.

Frequency Diverse Array Antenna: New Opportunities

Abstract: i»?Phased-array antennas are known for their capability to electronically steer a beam with high effectiveness, but beam steering is fixed in an angle for all range cells. This paper reviews frequency diverse array (FDA) antennas. Different from a phased array, an FDA uses a small frequency increment, as compared with the carrier frequency, across array elements. The use of a frequency increment generates an array factor that is a function of the angle, the time, and the range, allowing the FDA antenna to transmit the energy over the desired range and angle. In addition to analyzing FDA factor characteristics, this paper investigates FDA potential applications in range-dependent energy control and technical challenges in system implementation, with an aim to call for further investigations on the FDA.