Duke University

Michael Boyarsky

David R Smith

Seyedmohammadreza Faghih Imani

Timothy A Sleasman

Jonah N Gollub

Laura Pulido Mancera

Thomas Fromenteze

An apparatus includes a traveling-wave antenna array comprising a plurality of adjacent metamaterial surface antennas comprising a waveguide or a cavity, each adjacent metamaterial surface antenna comprising an array of metamaterial radiators coupled to a surface of the waveguide or the cavity, each metamaterial radiator comprising an individually addressable tunable component that can be tuned over a spectral bandwidth to generate different radiation patterns. The apparatus further includes a phase diversity feed coupled to the traveling-wave antenna array and configured to provide adjustable phase diverse input to two or more of the plurality of adjacent metamaterial surface antennas, the phase diverse input comprising a first phase for a first traveling-wave antenna and a second phase for a second traveling-wave antenna, the first phase being different from the second phase, wherein the phase diverse input is-selected to suppress grating lobes for a directed beam pattern selected for transmission.

Phase diversity input for an array of traveling-wave antennas

According to various embodiments, systems and methods for spatial sampling in proximity to the Nyquist limit in traveling-wave antenna systems are disclosed. An apparatus can include a traveling-wave antenna array comprising a plurality of adjacent traveling-wave antennas that each include a plurality of tunable elements that are spaced at, near, or above a Nyquist limit spacing to form an array of tunable elements. The apparatus also includes a phase diversity feed coupled to the traveling-wave antenna array that is configured to provide input to the traveling-wave antenna array including phase diverse input to two or more of the plurality of adjacent traveling-wave antennas. Further, the apparatus includes a plurality of grayscale tuning elements configured to tune the plurality of tunable elements along one or more ranges of one or more tuning variables to form one or more specific output radiation patterns through the traveling-wave antenna array based on the input.

Nyquist sampled traveling-wave antennas

According to various embodiments, systems and methods for suppressing grating lobes in a traveling-wave antenna system are disclosed. An apparatus can include a traveling-wave antenna array comprising a plurality of adjacent traveling-wave antennas. The apparatus also can include a phase diversity feed coupled to the traveling-wave antenna array. The phase diversity feed can be configured to provide phase diverse input to two or more of the plurality of adjacent traveling-wave antennas.

A single frequency, or very narrow frequency band, microwave imaging system is described herein. A microwave imaging system can include an array transmitter; an array receiver; and a computing device that receives signals detected from the array receiver, transforms the signals received by the array receiver into independent spatial measurements, constructs an image using the independent spatial measurements, and outputs a reconstructed image. The array transmitter and the array receiver may each have a plurality of independently controllable metasurface resonant elements.

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Durham, NC, United States of America

Michael Boyarsky