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Handbook of High Temperature Superconductor Electronics Part 14

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Tham khảo tài liệu 'handbook of high temperature superconductor electronics part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 13 High-Temperature Superconductor Electronics Status and Perspectives Shoji Tanaka Superconductivity Research Laboratory ISTEC Tokyo Japan 13.1 INTRODUCTION After the discovery in 1986 many kinds of high-Tc superconductor HTS have been found and the critical temperature was raised up to 130 K in mercury-based compounds. In the first 10 years however they have been the objects of material sciences primarily because they are quite peculiar cuprates and it was necessary to understand the physical properties chemical properties and so on. At around 1995 the trends in the applications of HTS became clear. The development of microwave filters and superconducting quantum interference devices SQUIDs have been accelerated. Furthermore the applications of well-known low-Tc superconductors LTSs were stimulated by the progress of HTS research and developments and the application of LTS SQUIDs to medical electronics and study of single flux quantum SFQ devices started. As for materials for the LTS devices only Nb-based compounds are used. Over the past 20 years the progress of the Internet has been remarkable and it covers the whole world and is changing the structure of our society to form the so-called ubiquitous society. Superconductivity electronics must have a great impact on the progress of the Internet as will be mentioned in this chapter. Copyright 2003 by Marcel Dekker Inc. All Rights Reserved. 13.2 MICROWAVE FILTERS High- Tc superconductor microwave filters and low-noise amplifiers for mobile telephone base stations have been the first commercialized devices in HTS electronics. HTS-based systems offer an improved quality in wireless communications with increased area coverage and reduced interference. Currently the mobile telephone system is connected to the Internet and service is widely improved e.g. i-mode . Especially in Japan third-generation 3G wireless communication began last year in major cites which is close to becoming a picture phone system. The area of .