Masters Theses


"Spring clips and fabric-over-foams (FOFs) are widely used in mobile devices for electrical connection purposes. However, the imperfect metallic connections tend to induce passive intermodulation (PIM), resulting in a receiver sensitivity degradation, known as RF desensitization. Due to the complexity of the PIM characterization, there is not yet a way to evaluate PIM performance using a simple setup for environments like factories. In this study, a current-voltage (I-V) behavior-based PIM evaluation method is proposed and validated with various metallic contacts and contact forces. The test results demonstrated the feasibility of the PIM performance evaluation based on the measured static I-V curve.

After the I-V based PIM estimation, the impact of the aging environment on the level of passive intermodulation (PIM) and DC resistance of nickel-based conductive FOF materials presented. These materials are widely used to maintain metallic connections between modules and chassis in electronic devices. The PIM caused by the loose metallic contact of these materials mainly affects a receiver’s RF sensitivity in mobile devices. This aging test under elevated temperature and relative humidity conditions offers an experiment-based approach with respect to various metallic contact cases. Energy dispersive spectroscopy and scanning electron microscopy are used to characterize the change in material composition and the contact surface throughout the aging. The experimental environmental effects showed the aging on the generated PIM level to have little to no impact and DC resistance of these metallic contact materials increased"--Abstract, p. iii


Hwang, Chulsoon

Committee Member(s)

Beetner, Daryl G.
Kim, DongHyun (Bill)


Electrical and Computer Engineering

Degree Name

M.S. in Electrical and Computer Engineering


Missouri University of Science and Technology

Publication Date

Summer 2023


x, 40 pages

Note about bibliography

Includes_bibliographical_references_(pages 37-39)


© 2023 Kalkidan Wolemariam Anjajo, All Rights Reserved

Document Type

Thesis - Open Access

File Type




Thesis Number

T 12289

Electronic OCLC #