Aerospace and Electronic Systems Society [AES-10]

Photonics; Aerospace & Electronics Systems Societies and Women in Engineering

6:30 PM, Thursday, 13 June

Silicon Nanowires, Enabling Low Cost Photovoltaic Electricity

Marcie Black, Bandgap Engineering

Silicon nanowires can improve the optical properties of silicon solar cells, but commonly-held concerns about the effects of nanostructuring on device performance have limited their adoption. Here we present experimental results of our design and processing innovations applied to silicon-nanowire solar cells that confirm the excellent anti-reflection and absorption benefits, demonstrate high minority carrier lifetime and efficiencies >18%. Nanowires enhance the efficiency of crystalline silicon solar cells by reducing reflection over a broad range of incident wavelengths and angles: measured reflection is less than 1% for a weighted average over the solar spectrum. Furthermore, the nanowires increase the optical path length within the device, allowing the absorption of the silicon to approach the Lambertian limit for light trapping. This increased absorption improves efficiency for standard thickness cells (mainly in the infrared), as well as significantly increasing the amount of light absorbed in thin crystalline silicon cells. Our nanowire fabrication process is independent of crystallographic orientation and overall is especially well-suited for multicrystalline and thin crystalline silicon cells. Our nanowire solar cells are fabricated with a low-cost process and we will discuss the benefits of integrating them into existing solar cell production lines and how they can potentially increase the efficiency by 1% or more absolute and reduce costs by $0.05 – 0.10/Wp. We will also present how our nanowires enable several manufacturing improvements such as thin wafers, N-type wafers, passivated back contacts and plated front metal contacts to enable further cost and performance advantages with crystalline silicon wafers.

Marcie Black Photo Marcie Black is the co- founder and CTO of Bandgap Engineering. Bandgap Engineering is an early stage start-up seeking to commercialize high efficiency silicon solar cells. Dr. Black has dedicated her career to making renewable energy more cost effective. She has more than twenty years of technical experience in the semiconductor, opto-electronic, and solar energy industries. Before joining Bandgap Engineering, Marcie was a technical staff member at the Applied Electromagnetics Group at Los Alamos National Laboratory and worked on a variety of nanotechnology initiatives, optical systems, and photovoltaic projects. Prior to her PhD work at MIT, she was a device engineer at Motorola. In 2009, she was awarded an R&D 100 award for her contributions to work at LANL. In March 2010, Marcie was honored as one of the ten “Women to Watch in 2010” by Mass High Tech. She earned her PhD on the optical properties of bismuth nanowires in 2003 and her Masters of Engineering in 1995 on polysilicon optical waveguides, both from MIT’s Electrical Engineering department. Dr. Black has worked on thin film silicon, organic, quantum dot, and several other solar cell technologies and is the inventor of the Bandgap Activation approach applied to photovoltaics. She has published over 30 articles in peer- reviewed journals and 4 book sections, has had 8 patents issue with many more patents pending.

This meeting begins at 6:30 PM Thursday, June 13th, 2013 and will be located in the cafeteria at MIT Lincoln Laboratory, 244 Wood Street, Lexington, MA 02420. The meeting is free and open to the public. All are welcome. Prior to the seminar there will be social time and networking from 6:30 - 7:00PM in the MIT Lincoln Laboratory cafeteria, the seminar will begin at 7:00PM. For more information contact David Scherer, Boston IEEE Photonics Society Chapter chair at dscherer@symmetricom.com, or visit the Boston IEEE Photonics Society website at www.bostonphotonics.org.

Directions to Lincoln Laboratory: (from interstate I-95/Route 128)

From Exit 31B: Take Exit 31B onto Routes 4/225 towards Bedford - Stay in right lane; Use Right Turning Lane (0.3 mile from exit) to access Hartwell Ave. at 1st Traffic Light; Follow Hartwell Ave. to Wood St. (~1.3 miles); Turn Left on to Wood Street and Drive for 0.3 of a mile; Turn Right into MIT Lincoln Lab at the Wood Street Gate; Have a valid driver’s license to present to security.

From Exit 30B: Take Exit 30B on to Route 2A - Stay in right lane; Turn Right on to Mass. Ave (~ 0.4 miles - opposite Minuteman Tech.); Follow Mass. Ave for ~ 0.4 miles; Turn Left on to Wood Street and Drive for 1.0 mile; Turn Left into MIT Lincoln Lab at the Wood Street Gate; Have a valid driver’s license to present to security.

All attendees must present a valid driver's license to MIT Lincoln Laboratory security. To get to the Cafeteria, proceed toward the Main Entrance of Lincoln Laboratory. Before entering the building, proceed down the stairs located to the left of the Main Entrance. Turn right at the bottom of the stairs and enter the building through the Cafeteria entrance. The Cafeteria is located directly ahead.

Microwave Theory & Techniques; Aerospace & Electronic Systems; Signal Processing, and Antennas & Propagation Societies

6:00 PM, Tuesday, 28 May

MIMO Radar: Demystifies

Dr. Eli Brookner, Raytheon Co., IEEE AESS Distinguished Lecturer

First Multiple Input and Multiple Output (MIMO) radar is explained in simple terms. Where it is practical to use in the near terms is covered. Contrary to claims made MIMO radar does not provide an order of magnitude better angle resolution and accuracy over conventional radars. At best its accuracy is only a factor of 1/√2 (29 percent) better and its resolution is the same for a full monostatic array.

Alternately, at best a monostatic MIMO array radar can offer the advantage of the same accuracy as a conventional array radar with a smaller aperture size, one that is 1/√2= 0.707 smaller, or equivalently 29 percent smaller. The advantage of a possibly smaller antenna would be important where the antenna size is a driving factor. This advantage of better angle accuracy or smaller antenna size for a monostatic array of N elements comes at the need for ≥N times as much pulse compression match filtering and beamforming as needed for a conventional array.

Bistatic MIMO (Brookner, Eli, Microwave A MIMO array system consisting of a full transmit array and thinned receive array (called here a full/thin array) provides the same angle accuracy, resolution and identifiability (ability to specify the number of targets present) as its conventional equivalent, not orders of magnitude better performance. MIMO radar is best for search not for track, unless doing track-while-scan. MIMO in the near term will be useful for coherent and incoherent combining of existing radars to achieve effectively of the order of 9 dB better power-aperture-gain (PAG). MIMO has already been practically used for wireless communication systems, to provide increased data rate for a given bandwidth. As the cost of signal processing gets lower, MIMO should find more applications for radar systems.

Journal, Jan., 2013)

BEE: The City College of the City of New York, ’53, MEE and DrSc: Columbia University ’55 and ’62.

Eli Brookner Photo Dr. Eli Brookner has been with Raytheon Company since 1962, where he is a Principal Engineering Fellow. There worked on ASDE-X airport radar, ASTOR Air Surveillance Radar, RADARSAT II, Affordable Ground Based Radar (AGBR), major Space Based Radar programs, NAVSPASUR S-Band upgrade, COBRA DANE, PAVE PAWS, Missile Site Radar (MSR), COBRA JUDY Replacement, THAAD, Brazilian SIVAM, SPY-3, Patriot, BMEWS, UEWR, Surveillance Radar Program (SRP), Pathfinder marine radar, Long Range Radar (upgrade for > 70 ATC ARSRs), COBRA DANE Upgrade, AMDR, Space Fence, 3DELRR. Prior to Raytheon he worked on radar at Columbia University Electronics Research Lab. [now RRI], Nicolet and Rome AF Lab.

Received IEEE 2006 Dennis J. Picard Medal for Radar Technology & Application “For Pioneering Contributions to Phased Array Radar System Designs, to Radar Signal Processing Designs, and to Continuing Education Programs for Radar Engineers”; IEEE ’03 Warren White Award; Journal of the Franklin Institute Premium Award for best paper award for 1966; IEEE Wheeler Prize for Best Applications Paper for 1998. Fellow of IEEE, AIAA, MSS. He is an IEEE AESS Distinguished Lecturer.

Published four books: Tracking and Kalman Filtering Made Easy, John Wiley and Sons, Inc., 1998; Practical Phased Array Antenna Systems (1991), Aspects of Modern Radar (1988), and Radar Technology (1977), Artech House. Gives courses on Radar, Phased Arrays and Tracking around the world (25 countries). Over 10,000 attended these courses. Banquet/keynote speaker twelve times. >230 papers, talks and correspondences, >100 invited. Six paper reprinted in Books of Reprints (one in two books). Contributed chapters to three books.

Meeting is being held at MIT Lincoln Laboratory is located at 244 Wood St., Lexington, MA 02420. The cafeteria is open to the public and visitor parking is available adjacent to the main entrance (in front of the parking structure). The Laboratory is also accessible via MBTA Bus route 76. When entering the Wood St. gate and the Main Cafeteria entrance, please tell the guard on duty that you are a visitor attending the IEEE meeting. Refreshments are served at 5:30PM.

(Thanks to the Boston Photonics Society for the following directions.)

From interstate I-95/Route 128: Take Exit 31B onto Routes 4/225 towards Bedford - Stay in right lane; Use Right Turning Lane (0.3 mile from exit) to access Hartwell Ave. at 1st Traffic Light.; Follow Hartwell Ave. to Wood St. (~1.3 miles); Turn Left on to Wood Street and Drive for 0.3 of a mile.; Turn Right into MIT Lincoln Lab, at the Wood Street Gate.

From Exit 30B: Take Exit 30B on to Route 2A - Stay in right lane; Turn Right on to Mass. Ave (~ 0.4 miles - opposite Minuteman Tech.).; Follow Mass. Ave for ~ 0.4 miles.; Turn Left on to Wood Street and Drive for 1.0 mile.

Turn Left into MIT Lincoln Lab, at the Wood Street Gate.

To get to the Cafeteria, proceed toward the Main Entrance of Lincoln Laboratory. Before entering the building, proceed down the stairs located to the left of the Main Entrance. Turn right at the bottom of the stairs and enter the building through the Cafeteria entrance. The Cafeteria is located directly ahead.

For additional information, please contact Chris Galbraith at chris.galbraith@ll.mit.edu

Life Members (Boston and NH); Aerospace & Electronic Systems and Microwave Theory & Techniques Societies

4:00 PM, Wednesday, 24 April

Achievement and Future Trends in Phased Arrays and Radars

Dr. Eli Brookner, Raytheon Company

Covered will be recent developments in radar and phased arrays, including metamaterials, grapheme, digital beam forming, micromachining, low cost arrays, signal processing; Systems: 3, 4, 6 face “Aegis” systems developed by China, Japan, Australia, Netherlands, USA; Low Cost Packaging: Raytheon funding development of low cost flat panel X-band array using COTS type PCB; MA-COM/Lincoln-Lab. developing low cost S-band flat panel array using PCB, overlapped subarrays and a T/R switch instead of a circulator; Extreme MMIC: 4 T/R modules on single chip possible at X- costing ~$10 per T/R module; Digital Beam Forming: Israel and Australia “Aegis” AESAs have an A/D for every element channel, a major breakthrough; Lincoln Lab and AFRL X-band have 600 MHz instantaneous wideband DBF at element development effort; Low cost DBF at element arrays for on-the-move Ethernet by IMST; Lincoln Lab using 2W chip increases spurious free dynamic range of receiver plus A/D by 20 dB; Radio Astronomy scientists looking at using arrays with DBF; Materials: GaN advancing rapidly. Will be helped by use for PCs, notebooks, cell phones, servers and GaN LED industry where they are expected to replace incandescent bulbs $100 billion industry. With GaN can now put 5X to 10X the power of GaAs in same footprint; SiGe for backend, GaAs for front end of T/R module; Metamaterials: Can now focus 6X beyond diffraction limit at 0.38 μm – Moore’s Law marches on; French, ESPCI PARISTECH, demonstrated 40X diffraction limit, λ/80, at 375 MHz; Can extent to IR; Used in cell phones to obtain antennas 5X smaller (1/10th λ) and have 700 MHz-2.7 GHz bandwidth simultaneously serving GPS, Blue Tooth, Wi Max and WiFi; Provides isolation between closely spaced antennas and antenna elements, Un. Michigan demonstrated equivalence of 1m separation with only 2.5 cm separation of two antennas on a ground plane using electronic bandgap (EBG) material; n-doped graphene has negative index of refraction, first such material found in nature; potential being pursued for low cost electronically steered metamaterial passive phased array; Low Cost Systems: Valeo Raytheon (now Valeo Radar) developed low cost, $100s only, car 25 GHz 7 beam phased array radar; over 1 million sold already, more than all the radars ever built up to a very few years ago; Commercial ultra low cost 77 GHz Roach radar on 72mm2 chip with >8 bits 1 GS/s A/D and 16 element array; Un. Michigan developing low cost 240GHz 4.2x3.2x0.15 cm2 5 gm radar for bird inspired robots and crawler robots, Frequency scans 2ox8o beam ±25o; DARPA has goal to build 28,000 element 94 GHz array costing $1/element, 50W total RF peak power; SAR/ISAR: Principal Components of matrix formed from prominent scatterers track history used to determine target unknown motion and thus compensate for it to provide focused ISAR image; Army Research Lab demonstrated 12 dB reduction in sidelobes of forward looking SAR back projection images for IED ultra wideband radar by use of Recursive Sidelobe Minimization (RSM) Algorithm; Technology and Algorithms: MEMS: reliability reaches 300 billion cycles without failure, Can reduce the power amplifier (PA) count in an array by a factor of 2 to 4, can also be used as tuneable microwave filters, like 8-12 GHz with ~200 MHz BW; DARPA revolutionary COSMOS program: Will allow integration of III-IV, CMOS and opto-electronics on one chip without bonded wires, Lead to higher performance, lower power, smaller size, components; MIMO (Multiple Input Multiple Output): where it makes sense; Butler matrix using CMOS; Potential for terahertz clock speeds using graphene transistors, Could be used for non-volatile memory, flexible displays and camouflage clothing, self cooling, Can now be used as switch with 100,000 to 1 on/off ratio, IBM producing 200 mm wafers with RF devices; Potential use of electron spin for memory; Nonvolatile has high density, fast write and read speeds, low power, unlimited write endurance; Potential for use of 12 iron atoms for 1 bit of memory; provide hard drive with 100X density; Revolutionary 3-D Micromachining: integrated circuitry for microwave components, like 16 element Ka-band array with Butler beamformer on 13X2 cm2 chip; Iridium/GPS (IGPS) Positioning Navigation and Timing (PNT) system demonstrated ability to locate objects to within 1 cm in minute; 3D Dispay: 3D display from 2D image without the need for special eyeglasses. Can be used for displaying 3D SAR and ISAR image on our radar screens. Being used for video games; Superconductivity: We may still achieve superconductivity at room temperature. Superconductivity recently obtained for first time with iron compounds. May reveal what leads to superconductivity; DARPA UHPC Program: 100 GFlops in cell phone using only 2 W instead of the present required 600 W for the same throughput. Goal of DARPA-Intel UHPC program for 100 to 1000 reduction in computer required power by 2018; Biodegradable array of transistors or LEDs for detecting cancer or low glucose; can then dispense chemotherapy or insulin.

Dr. Eli Brookner, Raytheon Company, 528 Boston Post Road, Sudbury, MA 01776
Tel: 978-440-4007; e-mail: Eli_Brookner@raytheon.com
BEE: The City College of the City of New York, ’53, MEE and DrSc: Columbia University ’55 and ’62.

Dr. Eli Brookner Photo Dr. Eli Brookner at Raytheon Company since 1962, where he is a Principal Engineering Fellow. There worked on ASDE-X airport radar, ASTOR Air Surveillance Radar, RADARSAT II, Affordable Ground Based Radar (AGBR), major Space Based Radar programs, NAVSPASUR S-Band upgrade, COBRA DANE, PAVE PAWS, Missile Site Radar (MSR), COBRA JUDY Replacement, THAAD, Brazilian SIVAM, SPY-3, Patriot, BMEWS, UEWR, Surveillance Radar Program (SRP), Pathfinder marine radar, Long Range Radar (upgrade for 68 ATC ARSRs), COBRA DANE Upgrade, AMDR, Space Fence, 3DELRR. Prior to Raytheon he worked on radar at Columbia University Electronics Research Lab. [now RRI], Nicolet and Rome AF Lab.

The meeting will be held at the Lincoln Lab Auditorium, 244 Wood Street, Lexington, MA at 4:00 PM. Refreshments will be served at 3:15 PM. Registration is in the main lobby. Foreign national visitors to Lincoln Lab require visit requests. Please pre-register by e-mail to reception@ll.mit.edu and indicate your citizenship. Please use the Wood Street Gate. For directions go to http://www.ll.mit.edu/

For other information, contact Len Long, Chairman, at (781)894-3943, or l.long@ieee.org

Microwave Theory & Techniques, Photonics and Aerospace and Electronics Systems Societies

6:00 PM, 23 April

Simultaneous transmit and receive: a new capability to increase the utilization of the RF spectrum and improve the efficiency of systems that use the spectrum

Dr. Charles H. Cox, III, President of Photonic Systems, Inc.

The increasing (exploding?) trend to make almost everything wireless – from wireless mice to the wireless web – has put extreme pressure on what is basically a fixed resource: the RF spectrum. There are of course myriad approaches to meeting this challenge, including data compression schemes to reduce the amount of data that needs to be sent and spectral efficiency enhancements to increase the data that can be conveyed in a given bandwidth. But one avenue that has not been explored – at least until recently – is to use the same spectrum band to simultaneously transmit and receive (STAR). It was taken as axiomatic that this was not possible, and with good reason. To realize STAR, the isolation required between transmit and receive signals can exceed 100 dB!

Within the last few years, several design configurations have been proposed to implement STAR, or full duplex communication as the communications community prefers to refer to it. This talk will begin with an overview of the role STAR can play in addressing the spectrum challenge, as well as the technical performance, regulatory revisions and standard formats that must be realized for STAR to become viable. We will also briefly present an overview of the various approaches that have been proposed to implement STAR.

The talk will then focus on the design and performance of a STAR prototype developed by PSI. As one might expect, a STAR system design involves a large design trade space, because implementing STAR requires merging what have traditionally been two separate – and largely independent – design trade spaces: the transmit and receive paths. Hence in this talk we discuss in detail how investigators at Photonic Systems, Inc. (PSI) have addressed two of STAR’s most important challenges: dealing with the antenna return loss and achieving high T/R isolation. To achieve the required combination of bandwidth and antenna return loss improvement typically required for STAR turns out to be physically unrealizable, since such a combination of bandwidth and impedance match exceeds the Bode-Fano limit. Hence we describe an alternate approach that PSI has developed, which achieves the required performance. Key to achieving high T/R isolation is a new type of fiber-optic link we call TIPRx, for Transmit Isolating Photonic Receive link. As will also be described in the talk, TIPRx link combines the RF functions of a ferrite circulator and a low noise amplifier. Compared to a ferrite circulator, which typically achieves up to 20 dB T/R isolation over an RF bandwidth of one octave, we will show that a TIPRx has achieved > 40 dB over > 3 decades of RF bandwidth.

The talk will conclude with a hardware demonstration of a STAR system applied to the commercial FM radio band.

Charles H. Cox III Photo Charles H. Cox III ScD, is one of the pioneers of the field that is now generally referred to as analog or RF photonics.

Dr. Cox founded Photonic Systems Inc. in 1998 to provide expert engineering services in fiber-optic system design and to develop low-cost, high-performance fiber-optic links for government and commercial applications. Prior to organizing Photonic Systems Inc., Dr. Cox was on the research staff at MIT and at Lincoln Laboratory; he received his ScD from MIT in 1979.

Dr. Cox holds 10 US patents, has given 3 plenary and 71 invited talks on photonics and has published more than 70 papers on his research in the field of photonics. He has written a textbook titled Analog Optical Links, which was published in 2004, co-edited a book on milestone papers in photonics and written five book chapters. He is a fellow of IEEE and OSA. Dr. Cox served as a member of the Advisory Group on Electron Devices (AGED) from 2003 – 2009.

(Thanks to the Boston Photonics Society for the following directions.)

From interstate I-95/Route 128: Take Exit 31B onto Routes 4/225 towards Bedford - Stay in right lane; Use Right Turning Lane (0.3 mile from exit) to access Hartwell Ave. at 1st Traffic Light.; Follow Hartwell Ave. to Wood St. (~1.3 miles).; Turn Left on to Wood Street and Drive for 0.3 of a mile.; Turn Right into MIT Lincoln Lab, at the Wood Street Gate.

Turn Left into MIT Lincoln Lab, at the Wood Street Gate.

For additional information, please contact Chris Galbraith at chris.galbraith@ll.mit.edu