Sean P Duffy

US Patent:

8350767, Jan 8, 2013

Filed:

May 23, 2008

Appl. No.:

12/126418

Inventors:

Glenn A. Brigham - Chelmsford MA, US
Marat Davidovitz - Belmont MA, US
Zhanna Davidovitz, legal representative - Belmont MA, US
Sean M. Duffy - Stow MA, US
Jeffrey Herd - Rowley MA, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H01Q 1/28
H01Q 13/00
H01Q 1/00
H01Q 21/00
G01S 13/74
G01S 13/08

US Classification:

343725, 343705, 343785, 343722, 343776, 343853, 342 44, 342 51

Abstract:

Described are a notch antenna and an array antenna based on a low profile stripline feed. The notch antenna includes a planar dielectric substrate having upper and lower surfaces. Each surface has a conductive layer with an opening therein. A notch antenna element is disposed on the conductive layer of the upper surface at the opening. A stripline embedded in the planar dielectric substrate extends under the notch antenna element. The stripline is adapted to couple an RF signal between the stripline and the notch antenna element. A conductive via is electrically coupled to the stripline and extends from the stripline to the opening in the conductive layer on the lower surface so that the RF signal is accessible at the lower surface.

US Patent:

20020141027, Oct 3, 2002

Filed:

Oct 10, 2001

Appl. No.:

09/973873

Inventors:

Michael LaGasse - Lexington MA, US
Simon Verghese - Arlington MA, US
Sean Duffy - West Newton MA, US

International Classification:

G02F001/00

US Classification:

359/237000

Abstract:

A variable pulse width optical pulse generation system includes a first and a second optical interferometric modulator. A first drive signal applied to the first modulator modulates an input optical signal, so as to provide a first modulated optical signal. A second drive signal applied to the second modulator modulates the first modulated optical signal, producing output optical pulses. One or both of the drive signals may be formed by superposing a plurality of waveforms having different frequencies, for example a base frequency and its odd harmonics. By adjusting the relative amplitudes of the drive signals, or the relative amplitudes of the component waveforms forming the drive signals, the pulse width and the extinction ratio of the output pulses can be varied so as to achieve an optimal value.

US Patent:

20030020985, Jan 30, 2003

Filed:

Feb 15, 2002

Appl. No.:

10/077000

Inventors:

Michael LaGasse - Lexington MA, US
Simon Verghese - Arlington MA, US
Sean Duffy - West Newton MA, US
Lawrence Kushner - Andover MA, US
Barry Romkey - Burlington MA, US

International Classification:

H04J014/08
H04B010/06

US Classification:

359/135000, 359/189000

Abstract:

A demultiplexer is described that includes an optical splitter that receives an optical data signal having a plurality of data channels and that generates a plurality of identical optical data signals. An electrical clock recovery circuit receives the optical data signal and generates an electrical clock signal that is synchronized to the optical data signal and that has a frequency that is an integer multiple of a bit rate of one of the plurality of data channels. One of a plurality of phase shifters receives the electrical clock signal and generates a phase-shifted electrical clock signal in response to a control signal applied to one of the plurality of phase shifters. A respective one of a plurality of sampling circuits receives one of the identical optical data signals and the phase-shifted electrical clock signal and generates an electrical signal representing a data channel of the optical data signal.

US Patent:

20070210959, Sep 13, 2007

Filed:

Mar 7, 2006

Appl. No.:

11/369575

Inventors:

Jeffrey Herd - Rowley MA, US
Sean Duffy - Stow MA, US
Glenn Brigham - Chelmsford MA, US
Larry Retherford - Merrimack NH, US
Francis Willwerth - Arlington MA, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H01Q 3/00

US Classification:

342368000

Abstract:

Described is a tile module for a phased array system. The tile module includes array elements configured in a two-dimensional array which is part of a larger subarray in the phased array system. A control module communicates with each array element to control a phase shift and an attenuation. In one embodiment a two-dimensional overlapped subarray manifold provides a weighted combination of RF signals received by the array elements of the tile module and array elements of other tile modules disposed in the same subarray of the phased array system. In another embodiment the two-dimensional overlapped subarray manifold distributes to the array elements weighted combinations of transmit RF signals applied to the tile module and other tile modules disposed in the same subarray. Advantageously, tile modules can be fabricated in large quantities, can be tested and calibrated independently, and can easily be installed or replaced in the phased array system.

US Patent:

7061447, Jun 13, 2006

Filed:

Aug 2, 2004

Appl. No.:

10/911762

Inventors:

Carl O. Bozler - Waltham MA, US
Mark A. Gouker - Lexington MA, US
Sean M. Duffy - Newton MA, US

Assignee:

The United States of America as represented by the Secretary of the Air Force. - Washington DC

International Classification:

H01Q 15/02

US Classification:

343910, 343753

Abstract:

A reconfigurable antenna is presented that uses MEMs shutters to reconfigure a Fresnel zone plate antenna. It can be used to either point a main beam in different directions or to point multiple beams in different directions.