The study and design of various internal antennas built in real systems for commercial mobile communication

Abstract

Mobile communication antennas account for a significant portion of the antennas used by the general population and many businesses. The applications which use mobile antennas are found throughout a wide variety of the private, commercial and business sectors. As the mobile communication market is growing and being diversified, the antennas with the characteristics of a very small size, high efficiency, and high gain as well as a revolutionary design are being required. By requiring the aesthetic design and miniaturization of the antenna, the internal antenna (intenna) is spotlighted. However, it is needed to higher capacities than the external type antenna. Comparing with those type, it is difficult to optimize the parameters of the internal antenna performance, such as an impedance bandwidth, radiation patterns, and gain. In this thesis, various internal mobile antennas implemented inside real systems for wireless communications are proposed. By studying the antenna characteristics and performances, various interests and researches are explained such as motivations of the antenna, the design processes of the antenna, the principles of the antenna working, the application for commercial wireless devices, and $\It{etc}$.. Firstly, a novel miniature wideband internal antenna with dual monopole radiation elements for operating at multi-band handset applications is suggested. It consists of two radiation monopole elements with parallel connection in the limited handset interior space. The proposed antenna can be easily placed in practical handsets because of the small size of 20 $\times$ 17 $\times$ 3.5 $mm^{3}$. The measured bandwidth of the proposed antenna shows about 1 GHz from 1.71 GHz (DCS band) to 2.71 GHz (Bluetooth band) with VSWR below 2. It also resonates at GPS band of 1.57542 GHz. The electrical and structural characteristics of the proposed antenna make it attractive for use in mobile handset applications. Secondly, a compact internal antenna ...