Hope College Physics Department
Research Experiences for Undergraduates
|Project Title:||1Periodic Transmission Lines
2Electro-Mechanical Connections for High Temperature Superconductive Chips
|Student Name:||Andrew Bunnell|
|Student's Home Institution:||Hope College|
|Research Advisor:||Dr. Stephen Remnillard|
|Source of Support:||
is based upon work supported by a Cottrell College Science Award
from the Research Corporation for Science Advancement
and by the National Science Foundation under NSF-REU Grant No. PHY/
DMR-1004811, by an R&D contract from Mesaplexx, pty ltd., and by
the Hope College Division of Natural and Applied Science.
1Periodic transmission lines are a unique version of micro-strip transmission
line. Periodic inclusions create peculiar effects to radio waves passed through
the strip. These defects or additions model a crystal lattice which alters
the wave function through dispersion. The main motivation in studying periodic
transmission lines is to create an intermediate to advanced lab where students
will be able to review and apply many concepts they have learned in their studies.
Several basic principles include electric and magnetic field, capacitance,
resistance, inductance, and impedance. Several intermediate principles include
understanding the transmission and reflection coefficients by using S-parameters
from simulations and measuring strips using a vector network analyzer. Some
advanced steps include calculating the propagation constant, wave dispersion,
and forbidden zones resulting in band gap. Other parts of this lab include
using wet photolithography to create the Periodic transmission lines and using
MatLab to process and compare simulated, measured, and calculated data.
2For High Temperature Superconductive Chips (HTSCs) to be utilized in a system or as a device under test, they have to be carefully attached to a metallic harness and connected to signal leads. Manual attachment processes for superconducting chips were evaluated. The die attach included not only atmospheric and glove box low-temperature soldering but epoxy film was as well. Micro (electrical) connections were created using a Kulicke & Soffa manual wirebonder. These methods were examined for cost, durability, and repeatability. Furthermore, ease of fabrication, production time requirements, and training time estimation were scrutinized. Most of these variables improved with experience, and a program was developed to train students to quickly produce electrical and mechanical connections for HTSCs.
Short student instructional videos were created and posted on “You Tube” to facilitate rapid learning of the processes. The die attaching process was used for creating samples for additional HTSC research. Additionally beyond the scope of HTSCs, wirebonding was also utilized to assist a local small business, Lumenflow Corp, in developing prototypes of new low-Watt, ultra-bright LED light bulbs. These bulbs are the ‘next big wave’ for energy conservation in lighting.
Publications and Presentations:
"Even and Odd Order Nonlinearity from Superconductive Microstrip Lines,"Annelle M. Eben, V. Andrew Bunnell, Candace J. Goodson, Evan K. Pease, Sheng-Chiang Lee, and S.K. Remillard, IEEE Trans. on Applied Superconductivity, Vol. 21, no. 3, pp. 595-598, (2011).