Donald Plumlee

Energy scavenging device in LTCC materials

Energy scavenging devices can use environmental vibrations to power remote devices without the need for wires or batteries. This paper discusses the use of low temperature co-fired ceramics to design and fabricate a compact, multilayer coil to power an electromagnetic energy scavenging device

A PROTOTYPE CONTINUOUS FLOW POLYMERASE CHAIN REACTION LTCC DEVICE

There is a growing need for remote biological sensing in both laboratory and harsh field environments. Sensing and detection of biological entities such as anthrax, Ebola and other micro-organisms of interest involves sampling of the environment, amplification, analysis and identification of the target DNA. A key component of such a sensor is a low cost, portable, reusable, continuous flow polymerase chain reaction (PCR) thermal cycler. Fabrication with low temperature co-fired ceramics (LTCC) can provide a reusable low cost device capable of operating in a wide range of environments The design and manufacture of a prototype continuous flow micro-fluidic PCR device using low temperature co-fired ceramic is presented. Initial modeling of flow characteristics and heat transfer was carried out in SolidWorks™. The prototype device employs resistance heaters below the channels, buried and surface thermocouples for temperature monitoring, and air gaps for thermal isolation.

Development of a micro-nozzle and ion mobility spectrometer in LTCC

Multilayer ceramic packaging materials provide a versatile platform to fabricate a wide variety of devices from sensors to micro-nozzles. Our research is focused on developing robust sensors for underground deployment and monopropellant micro nozzles for satellite attitude adjustment applications. An LTCC monopropellant micro-nozzle is being developed and tested to provide small thrust vectors for satellite attitude adjustments. High purity hydrogen peroxide undergoes a strong exothermic decomposition reaction in the presence of a silver catalyst. A micro-nozzle and catalyst chamber has been designed to convert hydrogen peroxide liquid to functional thrust. The device uses internal fluidic channels to direct the propellant to a silver lined catalyst chamber. The catalyst decomposes the propellant into water vapor and oxygen at temperatures near 1029 K. The hot gases are then expelled through a contoured nozzle to provide thrust. Complex internal geometric features are created using a CNC milling machine. An ion mobility spectrometer (IMS) is being developed for permanent deployment below ground to continuously analyze groundwater pollutants. Each segment was constructed of multiple layers of green tape. Five Kovar inserts were embedded in the device to function as ion gates. Reduction in size, hermeticity and system integration was made possible by the novel use of LTCC packaging technology.

Fabrication of an Inductively Coupled Plasma Antenna in LTCC

With the size reduction of satellites, the need for miniaturized propulsion systems is increasing. This has led to research funding for the miniaturization of chemical and electric propulsion by NASA and the Air Force Office of Scientific Research (AFOSR). Miniaturized electric propulsion research has been an active area of interest recently. Electric propulsion systems are interesting candidates for miniaturization due to efficiency and the reduction in onboard propellant and the ability to apply existing techniques in electronic fabrication. A miniature electrostatic thruster is being developed in LTCC at Boise State University. The thruster is composed of an antenna to create the plasma, a cylinder to contain the plasma and grids to extract the plasma beam at high velocity. In this work, the development of the inductively coupled plasma (ICP) antenna in LTCC will be presented. This antenna is fabricated using DuPonts 951 Low Temperature Co-fired Ceramic (LTCC). A Direct Write is used to apply silver p...

Effects of Silver Paste Application on Embedded Channels in Low Temperature Co-Fired Ceramics

A monopropellant micropropulsion device is being developed in low-temperature cofired ceramics (LTCC). The device uses catalytic decomposition of hydrogen peroxide as a propellant: hence catalytic channels are embedded internally in these devices. Consistent construction of these channels depends on a wide range of variables both in the design and fabrication of the channel structures. The primary focus of this paper is the characterization of final channel geometry when silver paste is applied to the upper and lower surfaces of an embedded single layer channel. Application of silver paste to the upper and lower channel surfaces has been shown to alter the final shape of the channels within the test structure. Upper and lower surface deflection into the channel area is discussed and characterization of this phenomena is illustrated as a function of channel width. A design of experiment (DOE) method is used to explore how process parameters affect the channel geometry/integrity. Construction of the test st...

A phase-controlled magnetron using a modulated electron source

Magnetrons are efficient and robust, but phase-controlled magnetrons are difficult to implement. Our prior work [1] has used 2D simulations of a rising sun magnetron to demonstrate that the magnetron phase can be controlled by modulating the electron injection at discrete locations to control formation of the electron spokes. These results have further shown that such phase control can be achieved if only 10% of the injected current is modulated. We are currently designing a magnetron experiment that will use the 10-cavity circuit of a commercially available cooker magnetron from L3 Communications. Although the CWM-75KW magnetron can operate at high power (75 kW), our experiment will utilize the devices ability to operate at lower power and voltage (<;1.5 kW and <; -12kV) at 900 MHz. In addition, the device can operate at very low injected current (<;200 mA). The modulated current will be provided by Gated Field Emission Arrays [2] that have demonstrated current densities of 100 A/cm2 at a gate to emitter bias of <; 75 V. For this experiment, the GFEAs will only need to operate at a peak current density of <; 200 mA/cm2. The experiment will utilize a 10-sided faceted cathode constructed of a lower temperature co-fired ceramic (LTCC) that uses electron hop funnels to protect the GFEAs. Impedance matched address lines fabricated within the LTCC will drive the GFEAs which must be modulated at 900 MHz or an odd sub-harmonic (300 MHz). The cathode structure fabrication, GFEA implementation, drive electronics, and drive scheme will all be presented.

Electric Micro-Propulsion in Low Temperature Co-Fired Ceramics

This work focuses on the fabrication and assembly of miniature inductively-coupled plasma (ICP) electrostatic thrusters using DuPonts 951 Low Temperature Co-Fired Ceramics (LTCC). The use of LTCC allows for integration of electrical and fluidic features inside a hermetically sealed device that is resistant to plasma erosion. LTCC also allowed for the creation of cylindrical and planar structures which could be mated to form a single device. The thruster consists of a planar base, an antenna disc, and a plasma containment cylinder. The planar base contains internal fluid distribution channels as well as electrical interconnections. The antenna disc houses straight-through gas ports, electrical interconnects, as well as a planar spiral ICP antenna. The containment cylinder is used to contain argon plasma created by a radio frequency (RF) signal sent through the ICP antenna. The development of the fabrication process will be presented for the incorporation and alignment of all three LTCC components together...

Simulation and experimental analysis of a miniature ion thruster fabricated in low temperature co-fired ceramic

Summary form only given. Scaling down electric propulsion systems is of interest for the future development of propulsion systems for micro- and nano-satellites. Because of the low mass of nano-satellites, only a small amount of thrust, on the order of several hundred µN, is needed for tasks such as attitude control.

Miniaturized electric propulsion in Low Temperature Co-fired Ceramic

Miniaturized propulsion systems are of particular interest in the development of the newer generation of nano-satellites. These small satellites require a low-thrust propulsion system that is highly efficient in the use of propellant. Currently an electric propulsion device is being developed using the unique capabilities of Low Temperature Co-fired Ceramic (LTCC) materials to fit this purpose. In addition to being a stable, vacuum compatible material with high temperature capability, LTCC is a high permittivity material, with εr=7.8 and a loss tangent of 0.0061. The antenna design implements an Inductively Coupled Plasma (ICP) source2 using a spiral antenna embedded in the LTCC. The antennas spiral is fabricated in silver paste using a direct-write tool, and is in total 11cm long and 1cm in diameter. It is being analyzed for effectiveness in the range of 450MHz–1GHz; the high permittivity causes the length of the antennas spiral to be approximately one electrical wavelength long with respect to the operating frequency. This gives the antenna interesting characteristics within the 450MHz–1GHz range due to interference patterns generated by the relatively large length of the conductor and its spiraling pattern. As part of this project an analysis of the antenna characteristics and plasma coupling is being done using the COMSOL Multiphysics modeling software3 along with COMSOLs RF and Plasma Modules. The simulation results will be compared with the experimental results for the antenna and thruster assembly including antenna electric field patterns, plasma start power versus frequency and pressure, and plasma density measurements.

Design and Fabrication of LTCC Catalyst Chambers

The reduction in satellite size and mass presents the need to develop a proportionally smaller propulsion system for orbital station keeping. A liquid, monopropellant micropropulsion device made from Low Temperature Co-Fired Ceramics (LTCC) has been developed at Boise State University. This robust, simple design uses an embedded silver catalyst chamber to decompose a rocket-grade hydrogen peroxide monopropellant into a hot gas, which is then expelled out through a nozzle to generate thrust. Using LTCC eliminates the planar geometry fabrication constraint commonly found in silicon MEMS processing. This report presents the design and fabrication, and optimization of the hydrogen peroxide catalyst chamber used in these monopropellant microthrusters. Using the standard fabrication process for LTCC an initial prototype was developed. The design of this initial device was developed to measure the efficiency of the catalyst chamber by evaluating the ability of the device to decompose hydrogen peroxide. Catastrop...