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2013 IEEE International Symposium on Phased Array Systems & Technology
15 - 18 October 2013 Waltham, Massachusetts USA
Tutorial: Microwave Array Beamforming: Analog, Digital, and Photonic
Microwave Array Beamforming: Analog, Digital, and Photonic Dr. Hans Steyskal, Arcon Dr. Paul Juodawlkis, MIT Lincoln Laboratory Dr. Jeffery Herd, MIT Lincoln Laboratory 
Tutorial Overview: This tutorial covers the fundamentals of microwave phased array beamforming with analog, digital, and photonic implementations. The course will first review the basics of phased arrays, including electronic beam steering and control, error effects and calibration, pattern synthesis, and wide bandwidth implementations. Analog beamforming techniques such as corporate feed networks and multiple beam lens-based approaches will be described. Digital beamforming (DBF) array techniques will then be described in detail. DBF arrays digitize the received signals at the element level, thus preserving the total information available at the aperture, and then process these signals in the digital domain to form the desired beams. The course will review basic DBF system requirements and highlight several practical applications which are difficult or impossible to perform in the analog domain. Photonics applications for phased arrays will be discussed, including an overview of the current state of the art. Specific applications such as wideband, high dynamic range signal remoting and wideband true time delay beamforming will be highlighted. Finally, a set of array beamforming design examples will be shown which emphasize the tradeoffs that exist between the analog, digital, and photonic beamforming alternatives. Outline: 1. Fundamentals of Phased Array Beamforming (~30 min) o Phased array basics (electronic beamsteering, phase shifters) o Minimum # controls required o Pattern synthesis (low SLL, nulling, sector patterns) o Error effects / calibration (Ruze diagram, examples) o Calibration approaches o Wide bandwidth effects (beam squint, gain loss) 2. Analog Beamforming Technology (~30 min) o Corporate feed networks o Analog multiple beam approaches (Rotman lens, Butler matrix, R-2R) o Wideband analog beamformers (combiners, analog true time delay units) o Limited field-of-view beamformers (Overlapped subarrays) 3. Digital Beamforming Technology (60 min) o Digital vs analog beamforming o Intrinsic benefits of DBF o Digital receiver types o DBF system bandwidth and dynamic range o ADC performance o DBF processing requirements o Spatial Multiplexing o Adaptive beamforming o Direction of Arrival Estimation o MIMO array beamforming for com and radar o Conclusion ( future trends / challenges, incl. Compressive Sensing –  with help, please ) 4. Photonics Applications for Phased Arrays (~60 min) o Photonic technologies overview o Intrinsic benefits of photonics for phased array applications o Photonics for array signal remoting o Photonics for wideband true time delay beamforming 5. Array Beamforming Tradeoffs: Design Examples and Discussion (~60 min) o Multifunction phased array radar (MPAR) (digital multi-beam clusters, digital OLSA architecture, photonic remoting, …) o Ultra-Wideband Array (e.g. 6-18 GHz, small aperture ~16 x 16, photonic TDUs) o ‘Ubiquitous radar’ (broad TX, digital multi-beam RX, column or element level DBF) o Cell base station array (adaptive nulling on TX, RX, small ring array ~8-16 elements)  
Dr. Hans Steyskal received the degrees Civ. Ing., Tekn. Lic., and Tekn. Dr. in electrical engineering from the Royal Institute of Technology (KTH), Stockholm, Sweden in 1963, 1970 and 1973, respectively. In 1962, he joined the Swedish National Defence Research Establishment (FOA), where he investigated microwave radiation and scattering problems. In 1980 he joined the AF Research Laboratory, Hanscom AFB, MA, where he pursued research in electromagnetics, phased array antennas, and digital beamforming.  In 2007 he retired from the position AFRL Senior Scientist, Antennas and now works as a consultant. Dr. Steyskal has held a part-time position as Adjunct Professor in Antenna Technology at KTH in 1996-2004, and has been a Visiting Scientist at the Polytechnic University of New York and at The Federal Institute of Technology, Lausanne, Switzerland. He has served two terms as Associate Editor for the IEEE Transaction on Antennas and Propagation. He is an AFRL Fellow and an IEEE Life Fellow. Biography Dr. Jeffrey Herd is Associate Group Leader of the RF and Quantum Systems Technologies Group at MIT Lincoln Laboratory. In this role, he is responsible for the leadership of Advanced RF Technology efforts. The Laboratory’s activities in this area include significant programs in developing future radars for air traffic control, weather surveillance, and airborne collision avoidance. Before joining Lincoln Laboratory in 1999, Jeffrey worked in the Sensors Directorate of the U.S. Air Force Research Laboratory. From 1992-1994, he was a visiting scientist at the Institute for High Frequency Physics at the German Aerospace Research Establishment (DLR) in Munich, Germany. He received his B.S., M.S., and Ph.D. degrees, all in Electrical Engineering, from the University of Massachusetts, Amherst.   
Dr. Paul W. Juodawlkis is the Assistant Leader of the Electro-Optic Materials and Devices Group at the Lincoln Laboratory, Massachusetts Institute of Technology (MIT), where he is leading research on semiconductor optoelectronic devices, integrated photonics, and microwave photonics.  His research efforts have focused on the development of optical sampling techniques for photonic analog-to-digital converters (ADCs), quantum-well electrorefractive modulators, high-power waveguide photodiodes, and high-power semiconductor optical amplifiers (SOAs) and their application in mode-locked lasers and narrow-linewidth external-cavity lasers.  Dr. Juodawlkis received the B.S. degree from Michigan Technological University, Houghton, the M.S. degree from Purdue University, West Lafayette, IN, and the Ph.D. degree from the Georgia Institute of Technology, Atlanta, all in electrical engineering.  Prior to his research and leadership activities in the Electro-Optic Materials and Devices Group (1999-present), he served as a radar systems engineer on a multi-sensor airborne testbed program at the Lincoln Laboratory (1988-1993), and as a member of the Ultrafast Optical Communications Laboratory (UFOCL) at Georgia Tech (1993-1999) where he investigated the ultrafast optical nonlinearities of low-temperature grown quantum-well materials and optical packet-switch architectures. Dr. Juodawlkis is a Fellow of the Optical Society (OSA) and a Senior Member of the IEEE.  He has authored or co-authored over 100 peer-reviewed journal and conference publications.  He was General Co-Chair of the 2012 Conference on Lasers and Electro-Optics (CLEO) and Program Co-Chair of the 2010 CLEO.  He is currently an elected member of the IEEE Photonics Society Board of Governors (2011-2013).  He has served as Chair of the IEEE Photonics Society Technical Committee on Microwave Photonics (2003-2006), Program Co-Chair of the 2003 Photonics Society Summer Topical Meeting on Photonic Time/Frequency Measurement and Control, and committee member of the International Topical Meeting on Microwave Photonics (2004, 2008).  He is also a Technical Steering Committee member of the Boston Chapter of the IEEE Photonics Society (1994-present).