Electrical and Computer Engineering ETDs

Publication Date

Summer 7-15-2018


The purpose of the research presented is to establish the viability of using capacitive based sensors for the purpose of hardware security at the Printed Circuit Board (PCB) level. Capacitive sensors are traditionally used to sense changes to the areas surrounding the sensing pads in applications such as sensing proximity, position, humidity, fluid levels and much more.

The specific sensor used for this research is an inductor-capacitor (LC) based Capacitance-to-Digital Converter. This configuration is virtually immune to EM noise because it is a tank circuit and therefore filters out the noise which, in the past, caused reliability issues with these types of sensors. The research results show that the security system is capable of detecting active tampering as well as sensing extremely small physical alterations made to the PCB, even if those changes occurred when the system was powered down.

In addition to establishing the viability of capacitive based PCB security, we assessed the relationship between the sensing pad sizes and the resolution of the sensing pad. Many factors affect the resolution of the sensing pads, the term resolution meaning how small of a change the pads can detect reliably. These factors include the presence of power and ground planes, floating copper, active shielding, as well as environmental factors such as variations in temperature, humidity, and physical distance to surrounding objects.


Hardware Security, Printed Circuit Board, Physical Tampering, Active Protection

Document Type




Degree Name

Electrical Engineering

Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Jim Plusquellic

Second Committee Member

Payman Zarkesh-Ha

Third Committee Member

Calvin Chan