An ultrawideband (UWB) antenna has been developed for operation in the 200 MHz to 18 GHz frequency range. This antenna is a new type — a miniaturized offset bicone/dipole design that allows for vertically polarized omnidirectional coverage over an instantaneous 90:1 bandwidth. Numerical electromagnetic simulations with the finite-element method (FEM) were used to investigate the antenna concept and optimize geometry prior to fabrication. Measurements both in a compact range and in an anechoic chamber confirm the antenna’s performance.
John Sandora is an engineer at MIT Lincoln Laboratory’s “Advanced RF Sensing and Exploitation” group. Mr. Sandora received Bachelor’s degrees in physics and electrical engineering in 2004 and a MSEE in 2005 from The Ohio State University. As a Graduate Research Assistant he constructed a state-of-the-art compact range radar system which can measure the scattering and radiation characteristics of objects as large as twelve square feet. His thesis topic, “Design of the ElectroScience Lab’s 0.4 – 100 GHz Compact Range Radar System” won Outstanding Thesis in 2005. After joining MIT Lincoln Laboratory, he has continued working on radar, antenna design, RF systems analysis, and other advanced applied electromagnetics.
The meeting will be held at the MIT Lincoln Laboratory Cafeteria in Lexington, MA. Refreshments will be served at 5:30; the talk will begin at 6:00 pm. The talk is open to the general public.
Directions to Lincoln Laboratory Cafeteria from points north: Take I-95/128 south to exit 31B, Routes 4 & 225 towards Bedford. Stay in right lane and use the right turning lane (0.3 miles) to access Hartwell Ave at first traffic light. Follow Hartwell Ave to the end; take a left onto Wood Street (just before the AFB gate). Lincoln Laboratory entrance is 0.5 miles on right. The entrance to the cafeteria is on the lower level left of the main entrance.
From points south: Take I-95/128 north to exit 30B, Route 2A west. Turn right on to Mass Ave (~0.4 miles). Turn left on to Wood Street (~0.4 miles) Lincoln Laboratory Wood Street entrance is 1 mile on left. The entrance to the cafeteria is on the lower level to the left of the main entrance.
For more information contact John Sandora (jsandora@ll.mit.edu).
Everything changes across some temporal or spatial scale, and the lack of well-developed techniques for modeling changing statistical moments in our observations has stymied the application of stochastic process theory for many scientific and engineering applications. Non-linear effects of the observation methodology, i.e. the role of the observer, present one of the most perplexing aspects to modeling non-stationary processes. For example, such non-linear effects are problematic when averaging high-resolution radar data to match courser resolution radiometer data in combined retrieval algorithms. These limitations were encountered when modeling temporal effects of calibration frequency on the performance of a radiometer with non-stationary receiver fluctuations. A microwave radiometer is frequently calibrated to correct for fluctuations in the receiver. A radiometer typically samples a set of stable calibration noise references from which the receiver response is estimated. Algorithms are usually applied to suppress receiver fluctuations from the estimates of the measurements. Analysis has shown that algorithms designed to accentuate temporal effects in the receiver response yield information about the non-stationary properties of the receiver fluctuations. Ensemble Detection and Analysis extends this concept to the study of non-stationary signals as a form of noise assisted data analysis. This presentation will describe a novel approach to analyzing and modeling non-stationary processes using methods derived from techniques for analyzing and modeling radiometer systems including their calibration architecture and will conclude with musings on the ontology of a new Observation Theory.
Dr. Paul Racette is a member of the senior technical staff at the NASA Goddard Space Flight Center where he has worked since 1990. He has conceived, developed and successfully deployed several microwave to submillimeterwave remote sensors. He has participated in and led numerous field campaigns around the world. For his accomplishments in developing remote sensing technologies, Dr. Racette received NASA’s Medal for Exceptional Service and was the first recipient of NASA Goddard’s Engineering Achievement Award. In 2005 he became a NASA Administrator’s Fellow. Dr. Racette is an observation theorist with research interests that include the study and modeling of non-stationary processes, calibration methodologies and the role of consciousness in the evolution of the universe. Dr. Racette is an active volunteer for the IEEE, serves as Editor in Chief of IEEE’s www.earthzine.org and is an ex-officio AdCom member of the IEEE Geoscience and Remote Sensing Society. He received the Bachelor (1988) and Master (1990) of Science in electrical engineering from the University of Kansas and in 2005 completed his Doctor of Science in electrical engineering from The George Washington University. Dr. Racette is committed to the exploration and promotion of diversity in the workplace and serves as the co-Vice Chair of Goddard’s Native American Advisory Committee.
This meeting of the Geoscience and Remote Sensing Society Chapter will be held at the MIT Lincoln Laboratory cafeteria. Refreshments will be served at 5:30 PM with the technical meeting starting at 6:00 PM. A no-host dinner with the speaker will follow at a local restaurant. Directions to Lincoln Laboratory, 244 Wood St., Lexington: From I-95 (Rt. 128), take Exit 31B (Rt. 4-225) toward Bedford. At first stoplight, take jug handle left (bear right to take a left) onto Hartwell Ave. Proceed ~1 mile and take left on Wood St. Take first right to Lincoln Laboratory entrance. After passing guard, follow road around to parking lot on the right. Park. Walk to area between the main entrance and the parking garage and proceed down staircase (left side of main entrance) to the cafeteria entrance. For more information contact Bill Blackwell at (781) 981-7973 or wjb@ll.mit.edu
