Browse Prior Art Database

BELT LOOP ANTENNA

IP.com Disclosure Number: IPCOM000005991D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-22
Document File: 1 page(s) / 51K

Publishing Venue

Motorola

Related People

Michael Goldenberg: AUTHOR

Abstract

As paging products decrease in size, it becomes increasingly difficult to satisfy all of the radio design criteria since physical size is often an important design parameter. When designing a radio receiver for example, one of the most critical and challenging components to develop is the antenna. Common loop antennas need to enclose as great an area as possible for peak performance. Unfortunately, antennas are typically allocated a limited and often insufficient portion of the product's volume. This directly impacts the radio's sensitivity.

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MOlVROLA Technical Developments October 1990

BELT LOOP ANTENNA

by Michael Goldenberg

   As paging products decrease in size, it becomes increasingly difficult to satisfy all of the radio design criteria since physical size is often an important design parameter. When designing a radio receiver for example, one of the most critical and challenging components to develop is the antenna. Common loop antennas need to enclose as great an area as possible for peak performance. Unfortunately, antennas are typically allocated a limited and often insufficient portion of the product's volume. This directly impacts the radio's sensitivity.

   Another aspect to good antenna design relates to its position and direction in regards to the human body. Proper alignment of the antenna loop will improve antenna performance (correct alignment would be as that of a belt loop). It is therefore necessary to consider this requirement at the beginning of a pager's development.

   Interestingly, there exists an unused "dead" space in all belt-worn pagers. This is the area enclosed by the belt clip loop. It makes sense to attempt to use this area as the antenna loop since it will always exist at a constant size (since pagers will have to accommodate all belts), and it is also in the proper orientation. Unfortunately, for a belt clip to operate, it is necessary for it to open to allow it to clamp over clothing fabric. If an antenna were imbedded within the clip, this would open the loop, rendering...