Related Resources: instrumentation

Electromagnetic Shielding Characterization of Gaskets

Engineering Applications and Design

Engineering Physics

Electromagnetic Shielding Characterization of Gaskets
Electromagnetic Fields Division
Electronics and Electrical Engineering Laboratory
National Institute of Standards and Technology

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Open: Electromagnetic Shielding Characterization of Gaskets

Numerous measurement methods are used for determining the shielding performance of rf gaskets, but different methods give significantly different results for the same gasket. Various measurement methods and the reasons for the discrepancies are reviewed. Simple models and theories are used to explain the meaning of transfer impedance and shielding effectiveness for gaskets and to determine the frequency range of validity. Transfer impedance should be a valid characterization at low frequencies, and shielding effectiveness is more appropriate at high frequencies. The precise frequency limitations of these characterizations and current measurement methods are not well known, but a time-domain method is proposed for determining gasket properties over a broad frequency range.

Key words: coaxial fixture; gasket; reverberation chamber; shielded room; shielding effectiveness; slot; transfer impedance

TOC

Abstract 1
1. INTRODUCTION 1
2. TWO-DIMENSIONAL MODEL 2
2.1 Analytical Results 2
2.2 Transfer Impedance 6
2.3 Shielding Effectiveness 9
3. SLOTS OF FINITE LENGTH 10
3.1 Short Slots 10
3.2 Long Slots 12
4. GASKET MEASUREMENTS 15
4.1 Measurement Geometries 15
4.2 Measured Data 16
5. CONCLUSIONS AND RECOMMENDATIONS 19
6. REFERENCES 20