Browse Prior Art Database

ADVANCED EMI & RFI SHIELDING ARCHITECTURE

IP.com Disclosure Number: IPCOM000007965D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2002-May-09
Document File: 3 page(s) / 120K

Publishing Venue

Motorola

Related People

Andrew Guzik: AUTHOR [+3]

Abstract

The high performance portable communication device, has many individual circuitries of the receiver, transmitter or controller board, shielded from each other to prevent near field electro- mag- netic interference. Presently, to achieve required shielding effectiveness for given circuitry, the enclosed metal cans are soldered to the PCB to assure desired signal attenuation. To efficiently uti- lize an automated production line, it is desired to reflow all electronic components and shields at the same time. As a result of that, a significant number of electronic components are covered by the shields. This creates two major manufacturing prob- lems. First, there is no reliable way to provide con- sistent, good solder joints for the surface mounted components under the shield. Second, a visual inspection of components, or board repairs, are impossible without removing the cans. To resolve these manufacturing problems the new shielding architecture approach with the partition fence and cover was introduced.

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MOIOROLA Technical Developments

ADVANCED EMI & RFI SHIELDING ARCHITECTURE

by Andrew Guzik, Richard Ceraldi and Mac William Branan

  The high performance portable communication device, has many individual circuitries of the receiver, transmitter or controller board, shielded from each other to prevent near field electro- mag- netic interference. Presently, to achieve required shielding effectiveness for given circuitry, the enclosed metal cans are soldered to the PCB to assure desired signal attenuation. To efficiently uti- lize an automated production line, it is desired to reflow all electronic components and shields at the same time. As a result of that, a significant number of electronic components are covered by the shields. This creates two major manufacturing prob- lems. First, there is no reliable way to provide con- sistent, good solder joints for the surface mounted components under the shield. Second, a visual inspection of components, or board repairs, are impossible without removing the cans. To resolve these manufacturing problems the new shielding architecture approach with the partition fence and cover was introduced.

  The objective of this design is to provide the new shielding architecture that will allow easy access to electronic components under the shield.

  This design will be described using Fig. 1. The multi partition metalized fence (30) with a ,030 to ,040 wall thickness is designed to be soldered to the cladded pads (20) of the printed circuit board (lo), in order to provide shielding between adjacent cir- cuitries. The fence (30) is molded from Ultem 6200 and electrolessly plated to deposit the required thickness of copper-nickel metalization (20 microinches of nickel over 40 microinches of cop- per) on the plastic. The top of the fence (30) has a

flat surface (60) to assure sufficient area for electri- cal interconnection and a strong mechanical bond to the top shield (40) by using conductive adhesive
(70). The bottom of the f...