ORCID Identifier(s)

ORCID 0009-0002-2500-4262

Graduation Semester and Year

Spring 2024



Document Type


Degree Name

Doctor of Philosophy in Electrical Engineering


Electrical Engineering

First Advisor

David Wetz

Second Advisor

Wei-Jen Lee

Third Advisor

Chris Boyer

Fourth Advisor

Rasool Kenarangui


In high voltage pulsed power systems, liquids and gases are often used as insulating materials because they offer high breakdown strengths, conform around complex geometries, and are self-healing, but they can introduce significant engineering challenges and restrictions when it comes to implementing them. Solid dielectrics can be desirable for improving the maintenance requirements, shelf life, and power/energy density metrics associated with insulating high voltage pulsed power systems, however they possess design challenges of their own. Solid dielectrics are not self-healing and can be difficult to manufacture, especially around complex geometries. Epoxy dielectrics are of high interest because of their naturally high dielectric strength and their ability to fill complex geometries. Potting a system with a solid epoxy insulator is not uncommon, however it is imperative that the dielectric properties of the insulator be well understood since potted systems are nearly impossible to perform maintenance on, and a single breakdown event can cause a catastrophic failure requiring a full system replacement. The ability to alter the dielectric properties of solid insulators by introducing nanoparticle additives is also among their most attractive properties. Alteration of a dielectric’s permittivity can potentially be an advantageous design tool to help minimize electric field enhancements in high voltage system design. The ability to alter the permittivity of solid materials invokes an interest in pursuing functionally graded solid dielectrics, which utilizes composites to reduce electric field enhancements between dissimilar materials by implementing a spatial gradient of the dielectric permittivity between dissimilar materials. Achieving optimal dielectric properties through functional grading can significantly reduce electric field enhancements across boundary conditions and between dissimilar materials, potentially enabling systems to be designed more compactly. However, if the introduction of dielectric inclusions significantly reduces the material’s dielectric breakdown strength, even an optimized electric field profile may not be sufficient to compact a system design. In the work presented here, solid epoxy dielectrics that are both raw and dielectrically altered with the introduction of nanoparticle additives have been experimentally studied under both low voltage and pulsed high voltage experimental conditions to characterize their dielectric properties and evaluate their dielectric strength, respectively. Specifically, the relative permittivity and breakdown strength of EPON 815C epoxy is evaluated with several nanoparticle additives of interest at various loadings. Methods for fabrication and dielectric property measurement of nanocomposite epoxy dielectrics are presented, along with short-pulse breakdown testing results and permittivity measurement results across a wide frequency range. Finite element modeling and simulation techniques are also presented to predict how inclusions may alter permittivity and affect applied electric fields. It is shown in this work that the permittivity of the base material can be increased up to and beyond 80% of its original value within the scope of the studied material additives and loading percentages. These dielectric inclusions, however, are shown to significantly compromise the dielectric strength of the base material. It is theorized that the presence of additives causes localized electric field enhancements within the dielectric that statistically decrease the breakdown strength of the base material.


Pulsed Power, Dielectric, Breakdown, Permittivity, Insulator, Solid, Epoxy, Composite, Nanoparticle, Alumina


Electrical and Electronics | Other Electrical and Computer Engineering | Power and Energy


Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


This work was funded by NSWC-DD and ONR through Naval Engineering Education Consortium (NEEC) grants N00174-20-1-0025 and N00174-22-1-0023. The opinions and findings are those of the author and may not reflect those of the NSWC-DD or ONR.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.