Brian Dick

Development of a Ku-Band Corrugated Conical Horn Using 3-D Print Technology

We present the development of a Ku-band (10-16 GHz) corrugated conical horn antenna using 3-D print technology or stereolithography. The antenna is printed using acrylonitrile butadiene styrene (ABS), a thermoplastic, and then coated with conductive aerosol paint. The designed antenna achieves a measured peak gain of 19.6 dBi at 16 GHz with a 1.92:1 VSWR from 11 to 18 GHz. It is shown that 3-D printing is capable of producing sufficient feature sizes that make operation in the microwave/millimeter-wave (MMW) bands possible.

Optimization of kinetic energy harvester for low amplitude vibration

This paper presents the steps involved in optimizing the design of an electromagnetic kinetic energy harvester (KEH). The KEH device is conceptually a highly non-linear device. There are numerous dependent variables involved in the design of a KEH which are reliant upon the specific environmental conditions in which the KEH will be deployed. Furthermore, the non-linear nature of the device leads to an iterative design process. The environment that the KEH is deployed into also dictates the overall design and power per volume achieved by the device.

Development of kinetic energy harvesting systems for vehicle applications

This work demonstrates the implementation of a functional kinetic energy harvester designed to power wireless sensor electronics used in vehicular applications. The design, fabrication, and experimental characterization of a complete electrodynamic (magnetic) energy harvesting system capable of delivering in excess of 10 mW from 100 milli-gs of acceleration is presented. Unlike previous energy harvesting research, which typically focuses on individual components for proof-of-concept testing, the system implemented for this work includes the integration of a low-frequency transducer, power electronics circuitry, and a rechargeable storage element, all of which are required for a functional system. The design trade-offs, which result from the integration of these system components are examined and design rules for maximizing efficiency are given. Finally, field testing is presented, which demonstrates the ability of the system to operate over a range of different vehicle speeds.

Design and analysis of a novel electro-optical MEMS gyroscope for navigation applications

A novel gyroscope design is presented that has potential to reach navigation-grade performance, i.e. bias instability < 0.01 °/hr and Angle Random Walk (ARW) < 0.001 °/√hr. The design is based on the incorporation of an optical transduction mechanism used to decouple drive and sense signals, a dual crystalline silicon spring fabrication approach along with a large drive mass and small sense mass to enhance Coriolis displacement.

Powering of wireless sensors through the exclusive use of kinetic energy

This paper demonstrates the powering of wireless sensor nodes with the exclusive use of a novel kinetic energy harvester (KEH). This KEH is designed to operate under low accelerations which are practical to find in a typical environment where a sensor would be deployed. Four different sensor types were powered with accelerations ranging between 17–300mg.

Deployable wavelength optimizer for multi-laser sensing and communication undersea

This effort develops and tests algorithms and a user-portable optical system designed to autonomously optimize the laser communication wavelength in open and coastal oceans. In situ optical meteorology and oceanography (METOC) data gathered and analyzed as part of the auto-selection process can be stored and forwarded. The system performs closedloop optimization of three visible-band lasers within one minute by probing the water column via passive retroreflector and polarization optics, selecting the ideal wavelength, and enabling high-speed communication. Backscattered and stray light is selectively blocked by employing polarizers and wave plates, thus increasing the signal-to-noise ratio. As an advancement in instrumentation, we present autonomy software and portable hardware, and demonstrate this new system in two environments: ocean bay seawater and outdoor test pool freshwater. The next generation design is also presented. Once fully miniaturized, the optical payload and software will be ready for deployment on manned and unmanned platforms such as buoys and vehicles. Gathering timely and accurate ocean sensing data in situ will dramatically increase the knowledge base and capabilities for environmental sensing, defense, and industrial applications. Furthermore, communicating on the optimal channel increases transfer rates, propagation range, and mission length, all while reducing power consumption in undersea platforms.

Deployable wavelength optimization for free-space communication undersea

This effort develops autonomy algorithms and a portable optical system to optimize the undersea laser communication wavelength by probing the local seawater conditions via passive retroreflector, selecting the ideal wavelength, and enabling high-speed communication. Transmitting on the optimal channel increases transfer rates, propagation range, and mission length, all while reducing power consumption in unmanned undersea platforms. Additionally, optical meteorology and oceanography (METOC) data gathered and analyzed as part of the auto-selection process is stored and forwarded. We present autonomy software and man-portable hardware from the laboratory, and show a new system designed for operation in natural undersea environments.

Characterization and optimization of a novel electromagnetic transduction technique for rotational energy harvesting

A novel transduction technique that converts mechanical rotation energy to usable electrical energy using condensed magnetic flux is tested and characterized for a wind source. This rotation harvester is compared to the power output of a commercially available generator for a fixed wind source. Optimization of the rotation harvester is discussed in terms of various parameters, such as magnet spacing, number of excitation arms, rotation frequency, and harvester resonance.

Design of highly reflective subwavelength diffraction gratings for use in a tunable spectrometer

The design of highly reflective subwavelength gratings (SWGs) for use in a micro-electromechanical system (MEMS) tunable spectrometer is presented. The SWGs are designed to be polarization independent at an incident wavelength of 1.5 µm with high reflectivity over a 200 nm bandwidth. Two designs are considered; Model 1: a silicon layer with periodic air holes and Model 2: a stacked Si-SiO2-Si design with the last Si layer a periodic array of columns. The designs are simulated using a commercial rigorous coupled wave analysis (RCWA) software package. The RCWA software aids in the design of SWGs that have higher reflectance than traditional dielectric mirrors. Model 1 has a reflectance (R)≫0.99 for lambda 1.37–1.6 µm. Model 2 has a R≫0.99 for lambda 1.46–1.69 µm. Finally, both designs are modeled to create a Fabry-Perot cavity, and at an incident wavelength 1.5 µm, the designs have a reflection finesse of 1707 and 4452 for Model 1 and Model 2, respectively.