Poziv na predavanje: "Self-Calibration, Mutual Coupling Compensation and Thermal Management in Digital Beamforming Arrays"

Abstract

Electronically Scanned Arrays (ESA) with Digital Beamforming (DBF) are becoming the key component in commercial and military advanced radar and comm systems. As known, DBF is a powerful technique used to enhance the antenna performance through multiple beams, adaptive pattern control, element pattern correction, self-calibration, and flexible time management concepts. To fully exploit these advanced features and concepts that DBF arrays offer, it is crucial and necessary to perform the array calibration that works in real time and in the operational environment. Presently, the mutual coupling and digital errors in DBF arrays are combined in standard array calibration schemes performed at a single scan angle, typically broadside, and one frequency in anechoic chamber. The calibration errors increase at other scan angles. In addition, the method is not feasible in the field, i.e., in operational contested environments due to absence of the reference source, uncooperative transmitters i.e., interference, and unknown scattering from the environment.

Thus, there is a great need for the self-calibration and mutual coupling compensation in DBF arrays in real time while operating in contested environments. The potential benefits are enormous: improved array performance with ultra-low sidelobes while no additional hardware or external reference sources are needed.

Recent developments in mm-Wave Active Electronically Scanned Arrays (AESA) are the primarily focus on 5G applications requiring low transmit power.  For some applications where high transmit power is required, the thermal management becomes a serious challenge because of two reasons: poor efficiency of the power amplifiers and closely spaced radiating elements at mm-wave frequencies.  In this work we demonstrate the cooling system of a 256-element AESA operating at Ka-Band dissipating about 1kW over an area of less than 3 x 3 inches.

Biography

Boris Tomasic was born in Rijeka, Croatia, on August 8, 1945. He received the Dipl. Ing. degree in electrical engineering from Fakulteta za Electrotehniko, Univerza v Ljubljani, Slovenia, in 1971 and the M.S. and Ph.D. degrees in electrical engineering from Polytechnic Institute of New York, Brooklyn, NY, in 1975 and 1981, respectively.

From 1975 to 1980, he was a Research Assistant at Polytechnic Institute of New York, performing research on conformal and planar array antennas. Since 1981 he has been with the Air Force Research Laboratory (AFRL), Sensors Directorate, first at Hanscom AFB, MA and presently at Wright-Patterson AFB OH. From 2007 to 2011 he was the Technical Advisor in the Antenna Technology Branch wich has the responsibility for developing the technology base for antennas within the Air Force. Dr. Tomasic is responsible for planning and conducting research and development studies in the field of electromagnetic radiation, propagation and diffraction. His research interest is in the areas of antenna theory, planar and conformal phased arrays for airborne and space applications, mm-wave electronically scanned array antennas, digital beamforming, and metamaterials.

From 1981 to 1990, he was adjunct faculty member at the University of Massachusetts teaching graduate courses in electromagnetics and antenna theory. Dr. Tomasic is a member of Sigma Xi, URSI Commission B, and senior member of IEEE. From 1986 to 1989 and from 1997 to 1999 he served as associate editor for IEEE Transactions on Antennas and Propagation. He is an Air Force Research Laboratory Fellow and recipient of the 57th Annual Department of Defense Distinguished Civilian Service Award.