This paper presents an internal dual‐band antenna which has a planar‐type radiator and operates at the CDMA (824–894‐MHz) and PCS (1750–1870‐MHz) bands. The antenna characteristics at each band are optimized by tuning the size and length of the strip line's radiating segments. This antenna is composed of FR‐4 substrate (thickness of 1 mm), a planar‐type radiator, and 50Ω coaxial feeding cable. The maximum measured radiation gains are 0.94 and 1.89 dBi in the CDMA and PCS bands, respectively. The design of the proposed antenna and the experimental results are discussed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 537–540, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20872

A novel compact PCB printed quad‐band antenna using a composite loop and PIFA structure for mobile phones is presented. The proposed antenna is composed of a meandered loop antenna and PIFA having the merits of the loop antenna and PIFA. The antenna element is printed on the top ungrounded portion (34.5 mm (W) × 17 mm (L)) of a 0.8‐mm thick FR4 substrate of a mobile phone PCB. Despite the low volume and low profile of the antenna structure, it can fulfill the bandwidth requirements of the GSM900, DCS1800, PCS1900, and UMTS2100 systems with sufficiently high efficiency, thus making it a promising antenna candidate for future mobile terminals. The antenna design was carried out using a high‐frequency structure simulator (HFSS) by Ansoft, and the modeling structure of the mobile handsets was obtained with the aid of the commercially available simulation software SEMCAD. The overall radiation pattern is suitable for mobile applications. To demonstrate the proposed design, simulated and measured results are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1332–1336, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24309

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The most important cause for shortening LED lighting efficiency and life is the junction temperature rises and, to solve this problem, various studies such as thermally efficient packaging, highly conductive material development, contact resistance improvement or heat sink optimization have been studied. However, most studies so far assumed that the LED lights are in the atmosphere, and thermal performance has not been therefore reported when the LED lights are mounted on the ceiling with ceiling unit. Thus, this study investigates the variation of junction temperature of the MR16 LED light under actual installation conditions and more accurate thermal design for the efficiency and life of LED lights is therefore achieved.

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