Self-Contact Introduced Passive Intermodulation Characterizations for Captured Springs


Passive intermodulation (PIM) is one of the most common nonlinear behavior that exists in a variety of applications. Nowadays, consumer electronics designs use a variety of mechanical features for radio-frequency (RF) antenna feeds and grounding, such as springs, gaskets, screws, etc. When these components are placed in the path or nearby the RF antennas, the unsatisfying connection such as loose contact will generate PIM and create noise in the receiving frequency range. This can potentially cause RF desense issues. In product design, the most intrinsic method to improve the electrical connection is applying more compression between the spring tip and the landing substrate, but seldom will the engineers notice the spring structure itself can also introduce a lot of PIM. This paper concentrates on characterizing and validating the captured RF springs that can introduce noticeable PIM due to its structural self-contact phenomenon. An integrated camera recorded the spring side-view under compression. The measured information indicates that high PIM tends to occur when the spring contacts itself unintentionally.

Meeting Name

2021 IEEE International Joint Electromagnetic Compatibility Signal and Power Integrity and EMC Europe Symposium, EMC/SI/PI/EMC Europe 2021 (2021: Jul. 26-Aug. 13, Raleigh, NC)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory


This work was supported in part by the National Science Foundation (NSF) under Grant IIP-1916535.

Keywords and Phrases

Desense; Passive Intermodulation; Radio-Frequency Interference; Spring Component

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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Publication Date

13 Aug 2021