Publications

Antenna radiation patterns are typically measured using network analyzers, which are both expensive and physically large in size. These drawbacks can limit this test equipment's usage in universities that cannot afford to make such a purchase, as well as within applications that require mobile antenna measurements. An alternative approach is...

Many in-band full-duplex wireless systems transmit and receive on a single antenna to minimize redundancy and maintain compact form factors. For effective operation, all of these systems need to maximize transmit-to-receive isolation, which is limited by non-ideal antenna matching and non-zero circulator leakage. Several isolation-improvement techniques are investigated in this...

A switched array tile which is part of a large aperture for near-field microwave imaging is presented. The tile is based on the Boundary Array (BA), a sparse array topology for hardware efficient realization of imaging apertures. The larger array formed with the tile samples a scene with no redundancy...

In-band full-duplex wireless communications are challenging because they require the mitigation of self-interference caused by the co-located transmitter to operate effectively. This paper presents a novel tapped delay line RF canceller architecture with multiple non-uniform pre-weighted taps to improve system isolation by cancelling both the direct antenna coupling as well...

Spectroscopic ellipsometry is demonstrated to be an effective technique for assessing the quality of plasmonic resonances within aluminum nanostructures deposited with multiple techniques. The resonance quality of nanoplasmonic aluminum arrays is shown to be strongly dependent on the method of aluminum deposition. Three-layer metal-dielectric-metal nanopillar arrays were fabricated in a...

Radio astronomy using frequencies less than ~100 MHz provides a window into non-thermal processes in objects ranging from planets to galaxies. Observations in this frequency range are also used to map the very early history of star and galaxy formation in the universe. Much effort in recent years has been...

Many wireless devices have requirements that emphasize low size, weight and power for increased functionality and extended lifetimes. The additional complexity of these devices mandates the need to dynamically verify that all sub-system functions are fully operational. These tests can only be performed internal to the unit, and a circuit...

Simultaneous Transmit and Receive (STAR) systems typically utilize multiple cancellation layers to improve system isolation and avoid self-interference. The design of these different layers must be evaluated both individually and as a whole to determine their effectiveness in various environments. A flexible and reusable mobile testbed was constructed to aid...

Phased array technology has been evolving steadily with advances in solid-state microwave integrated circuits, analysis and design tools, and reliable fabrication practices. With significant government investments, the technologies have matured to a point where phased arrays are widely used in military systems. Next-generation phased arrays will employ high levels of...

We report our progress toward optimizing backside-illuminated silicon P-type intrinsic N-type complementary metal oxide semiconductor devices developed by Teledyne Imaging Sensors (TIS) for far-ultraviolet (UV) planetary science applications. This project was motivated by initial measurements at Southwest Research Institute of the far-UV responsivity of backside-illuminated silicon PIN photodiode test structures...