Developments in Mobile/Portable Telephones and Key Devices for Miniaturization

Shuuji URABE  Toshio NOJIMA  

IEICE TRANSACTIONS on Electronics   Vol.E79-C    No.5    pp.600-605
Publication Date: 1996/05/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on Microwave Devices for Mobile Communications)
mobile telephone,  portable telephone,  microwave devices,  Japanese cellular system,  radio unit design,  

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Fundamental microwave key devices used in achieving compact mobile/portable telephones (raidio units) are discussed. The historical development flow of the systems and radio units are introduced, with respect to the 800-/900-MHz and 1.5-GHz Japanese cellular radio systems. The design concept of the developed radio units is briefly described. Tehnical requirements for RF circuits are reviewed and the developed key devices are practically applied to the circuits. Key factors in the requirements are also shown. Finally. future trends fro the key devices are surveyed from the stand point of achieving a smaller and more light weight pocket radio unit.