Browse Prior Art Database

HOUSING COVER PLATES: BATTERY CONTACT AND ELECTROMAGNETIC WAVE COUPLER

IP.com Disclosure Number: IPCOM000006939D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2002-Feb-11
Document File: 3 page(s) / 148K

Publishing Venue

Motorola

Related People

Alien Hertz: AUTHOR [+4]

Abstract

Portable consumer electronic products, such as pagers, cellular phones, stereos, two way radios, and other receiving devices are becoming smaller while the number of features is increasing. To meet consumer demands, internal space must be optimized. One such form factor is the "credit card" design.

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INC. Technical Developments Volume 19 June 1993

HOUSING COVER PLATES: BATTERY CONTACT AND ELECTROMAGNETIC WAVE COUPLER

by Alien Hertz, Adrian Napoles, Diego Giannini and George Guzik

  Portable consumer electronic products, such as pagers, cellular phones, stereos, two way radios, and other receiving devices are becoming smaller while the number of features is increasing. To meet consumer demands, internal space must be optimized. One such form factor is the "credit card" design.

  Being roughly the length and width of a credit card and approximately 5 mm thick, the volume available for the electronics is crucial. The housing can be of sev- eral designs. One design is referred to as a tub which includes a molded plastic housing on four sides and the top or bottom. A single metal plate with a loop which serves as the antenna acts as the enclosure of the unit (bottom or top respectively). Another design is referred to as a frame which includes a plastic housing of four sides surrounding the unit and hvo (2) plates which serve as the antenna, the means to enclose the unit, and the top and bottom surfaces.

  Battery contacts normally occupy a high percent- age of the available space. Standard battery contact designs generally require .25" X .25" each. If the battery terminal opposing the polarity of the antenna plate is oriented towards the antenna, additional insulating mate- rials would be required to be attached to the plate to isolate the antenna from the battery. This would increase product costs and decrease field reliability. With a two plate design this would be mandatory on at least one plate. The insertion and removal of the battery would also cause. wear and/or peeling of the insulation.

  To eliminate these problems, the battery contact can be formed as part of the antenna plate. See Figure 1. The mechanical properties of the plate material can be used to form a cantilever spring which would deflect during battery insertion thus becoming a conductor from the battery to the electrical circuit. This would eliminate one or more components, and their associated tool and die costs, increase available real estate on the printed circuit board (PCB), eliminate requirements for all insu- lation materials, and increase manufacturabiity and field reliability

  Antennas are designed to transfer power from th...