Attenuating Tunnels for Accessing Shielded Enclosures

Authors: Vince Rodriguez
Publication: EMC Society of Australia Newsletter, June 2017, Issue 77
Copyright Owner: IEEE

RF shielded enclosures have been common features in laboratories and manufacturing areas for over 70 years. They provide an environment where work on RF can be performed without interference from outdoor sources. These shielded rooms and areas provide a place where classified frequencies and modulations can be used without leaking out. In general, these shielded rooms have shielded doors to maintain the shielding integrity. These happens until they are opened . To maintain the shielding integrity as personnel moves from the inside to the outside of the room and vice-versa, dual shielded doors with a small vestibule between them are used. However, the presence of multiple doors increases the time to access the enclosure. To solve this, some enclosures are designed featuring access passages to maintain the shielding integrity over a broad frequency without the use of doors. This type of access has been around for over 40 year but its design has never been discussed in the literature. In this paper, a door-less access is analyzed and some design rules are presented. The limitations of these tunnels are also presented. They do not have the shielding performance of a shielded door but they are ideal for certain applications.

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