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Method for cable shield grounding for an internal antenna

IP.com Disclosure Number: IPCOM000012021D
Publication Date: 2003-Apr-02
Document File: 3 page(s) / 118K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for cable shield grounding for an internal antenna. Benefits include improved performance.

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Method for cable shield grounding for an internal antenna

Disclosed is a method for cable shield grounding for an internal antenna. Benefits include improved performance.

Background

        � � � � � Coaxial or other cables are required to connect wireless local area networks (WLANs) and network interface cards (NICs). For many solutions, the coaxial cable must exit the chassis and continue to the antenna, as it does not work well within an electrically closed box. The exiting cable must have an electrical connection to the chassis to shunt current from internally coupled fields and prevent the cable from violating the electromagnetic interference (EMI) integrity of the system. The connection is required to be inexpensive, quick, and a nearly 360° electrical connection without using a separate connector that might add substantive cost.

        � � � � � Internal antennas introduce a new configuration as conventional cables exiting the chassis usually attach to longer cables. However, internal antennas are only a few centimeters or inches long. For this purpose, a less than perfect referencing connection (ground) can suffice if the connection is successful and the cable routing length is short.

        � � � � � A reference system with no cable demonstrates the EMI issue as antennas extended at various lengths cause the system to fail (see Figure 1). Successful internal antenna placement does not present a problem. The longer routing required by the duck design is a problem and results in EMI failure. If a chassis will not accommodate a good routing solution, grounding is required.

        � � � � � Some possible methods of referencing the antenna to the chassis include:

•        � � � � Feed-through connector, which requires a very expensive ($1-$2) for a 6-GHz cable

•        � � � � Spring-contact shield overlay, which requires the addition of the spring contact

•        � � � � Spring contact on the antenna backplane, which may require extra process steps when creating the antenna

        � � � � � If a cable is routed over 2 cm, the energy from within the chassis ca...