Compact wideband dual-band antenna suitable for thin internal mobile phone application is presented. This antenna has a simple structure and is formed by a printed monopole closely-coupled with a chip-inductor-loaded shorted strip. The antenna occupies a small board space of only about 180 mm2 on the system board and has negligible thickness, making it suitable for thin internal mobile phone. With the aid of embedding of a 15-nH chip inductor, the longer radiating strip has a length of about 39mm only (about 12% wavelength in free space at 900MHz), yet supports a resonant mode at about 900MHz for the lower frequency band to cover GSM900 operation (890–960MHz). The shorter radiating strip has a length of about 23 mm only (about 14% wavelength in free space at 1800MHz) and provides a resonant mode for wide frequency operation centered around 1800MHz for the antenna upper band to cover GSM1800/1900/UMTS operation (1710–2170MHz).
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