Massachusetts Institute of Technology

United States of America As Represented by the Secretary of the Air Force

Jeffrey Scott Herd

Marin Soljacic

Cheryl Marie Sorace-Agaskar

Dirk Robert Englund

Simon Verghese

Paul William Juodawlkis

Scott A Skirlo

Mihika Prabhu

Yi Yang

William F Moulder

George Barbastathis

Steven G Johnson

Suraj Deepak Bramhavar

Kenneth E Kolodziej

Marat Davidovitz

Boris G Kharas

Jamison Sloan

Samuel Kim

James D Krieger

Denise T Maurais-Galejs

Huy T Nguyen

Hans Steyskal

Josue Lopez

Alan J Fenn

Glenn A Brigham

Bradley Perry

Andrew Habib Zai

Peter T Hurst

Pierre A Dufilie

Sean M Duffy

Michael D Lockard

Leonard I Parad

Zhanna Davidovitz, Legal Representative

An integrated optical beam steering device includes a planar Luneburg lens that collimates beams from different inputs in different directions within the lens plane. It also includes a curved (e.g., semi-circular or arced) grating coupler that diffracts the collimated beams out of the lens plane. The beams can be steered in the plane by controlling the direction along which the lens is illuminated and out of the plane by varying the beam wavelength. Unlike other beam steering devices, this device can operate over an extremely wide field of view&#x2014;up to 180&#xb0;&#x2014;without any aberrations off boresight. In other words, the beam quality is uniform in all directions, unlike with aplanatic lenses, thanks to the circular symmetry of the planar Luneburg lens, which may be composed of subwavelength features. The lens is also robust to misalignment and fabrication imperfections and can be made using standard CMOS processes.

Planar Luneburg lens system for two-dimensional optical beam steering

A multistatic array topology and image reconstruction process for fast 3D near field microwave imaging are presented. Together, the techniques allow for hardware efficient realization of an electrically large aperture and video-rate image reconstruction. The array topology samples the scene on a regular grid of phase centers, using a tiling of multistatic arrays. Following a multistatic-to-monostatic correction, the sampled data can then be processed with the well-known and highly efficient monostatic Fast Fourier Transform (FFT) imaging algorithm. In this work, the approach is described and validated experimentally with the formation of high quality microwave images. The scheme is more than two orders of magnitude more computationally efficient than the backprojection method. In fact, it is so efficient that a cluster of four commercial off-the-shelf (COTS) graphical processing units (GPUs) can render a 3D image of a human-sized scene in 0.048-0.101 seconds.

Methods and systems for near-field microwave imaging

An integrated optical beam steering device includes a planar dielectric lens that collimates beams from different inputs in different directions within the lens plane. It also includes an output coupler, such as a grating or photonic crystal, that guides the collimated beams in different directions out of the lens plane. A switch matrix controls which input port is illuminated and hence the in-plane propagation direction of the collimated beam. And a tunable light source changes the wavelength to control the angle at which the collimated beam leaves the plane of the substrate. The device is very efficient, in part because the input port (and thus in-plane propagation direction) can be changed by actuating only logN of the N switches in the switch matrix. It can also be much simpler, smaller, and cheaper because it needs fewer control lines than a conventional optical phased array with the same resolution.

Methods and systems for optical beam steering

Systems and methods for improving power amplifier operation are provided. A system may include a baseband signal generator communicatively coupled to a baseband signal digital-to-analog converter. The baseband signal digital-to-analog converter may be communicatively coupled to two or more power amplifiers. The system may also include an envelope signal generator communicatively coupled to an envelope signal digital-to-analog converter. The system may further include a supply modulator communicatively coupled to the envelope signal digital-to-analog converter and the two or more power amplifiers for shared envelope tracking across the two or more power amplifiers.

Power amplifier operation

Described is a printed circuit antenna array including at least one castellated substrate. Also described is a stacked patch antenna array having at least one castellated substrate.

Stacked patch antenna array with castellated substrate

An antenna system capable of achieving simultaneous transmit and receive (STAR) operation over a wide bandwidth includes a ring array of TEM horn elements and a centrally located monocone or bicone antenna. The TEM horn elements each include a capacitive feed. The elements of the ring array are excited using a phasing scheme that results in signal cancellation at the location of the central element. The ring array may serve as either the transmit antenna or the receive antenna.

Wideband simultaneous transmit and receive (STAR) antenna with miniaturized TEM horn elements

Described is a simultaneous transmit and receive antenna system having a ring array of transmit antenna elements and a receive antenna element disposed on an axis that is perpendicular to and passing through the center of the ring array. Alternatively, the ring array includes receive elements and a transmit antenna element is disposed on the axis perpendicular to the ring array. Opposite antenna elements in the ring array differ in phase by 180&#xb0; so that a radiation pattern null occurs at the antenna element at the center of the ring array. Also included are at least one ground plane and an electrically-conductive cylinder disposed on the perpendicular axis inside the ring array to provide a high degree of isolation between the transmit and receive antenna elements. The system may be configured for wireless communications, for example, according to WIFI IEEE standard 802.11 or WIMAX IEEE standard 802.16.

Simultaneous transmit and receive antenna system

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.

Notch antenna having a low profile stripline feed

A reconfigurable microstrip antenna array geometry which utilizes Micro-Electro-Mechanical System (MEMS) switches to electrically connect groups of printed patch radiators for operation at multiple frequencies.

Reconfigurable microstrip antenna array geometry which utilizes micro-electro-mechanical system (MEMS) switches

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Rowley, MA, United States of America

Jeffrey Scott Herd