| With the rapid progress of modern wireless communication systems, mobile handsets demand low-profile multi-band internal antennas for different standards (DAMPS, GSM, DCS, PCS…). Comparing to traditional external antennas, internal antennas offer several advantages, such as less broken off, low specific absorption rates (SAR), easy mass production. The internal planar inverted-F antenna (PIFA) and wire inverted-F antenna (WIFA) are good candidates for a compact multi-band operation.The typical IFA includes a circuit ground, a radiation patch, a feed pin and a shorting mechanism. T he shorting structure can be realized through a shorting wall or pin. Comparing to the traditional quarter wavelength monopole, the patch size can be reduced at least 50%. Moreover, cutting the top patch into two or three sub-patches can meet the dual-band even multi-band operation. The effects of mobile handsets case and bandwidth are investigatedChapter 2 gives system concerns of mobile antenna design. The main parameters of mobile antenna, such as VSWR, return loss etc., are introduced. Furthermore, the radiation problems by SAR are considered in the chapter.Chapter 3 is devoted to an introduction of tri-band wire antennas for mobile communication. Antenna parameters studies are presented and practical design considerations for achieving high gain and wide bandwidth are given.In chapter 4, a novel PIFA with high radiation efficiency is designed for a tri-band mobile handset application. The design mainly consists of a slit patch to achieve the antenna size reduction and multi-band operation. Furthermore, A circular slit on radiation patch reduces the coupling between the antenna and speaker. The chapter also presents experimental results of the impedance bandwidth and radiation efficiency.In Chapter 5 and 6, the development and production of antenna are reviewed. Some basic engineering experience has been proposed to meet these manufacturing challenges. |
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