Slot Antenna Designs for Handheld Devices

• Main Authors: Chih-Kai Chang, 張智開
• Other Authors: Wen-Jiao Liao
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/7n7343

碩士 === 國立臺灣科技大學 === 電機工程系 === 104 === This thesis presents three slot antenna designs. Since slot antenna configuration is compatible with metal surfaces, we attempt to implement slot antennas with lumped elements to configure broadband antennas. The slot structure can be conveniently incorporated with metal frame, which is a welcome feature for trendy mobile device designs. The first design is a dual band WLAN 2.4/5 GHz two antenna system for handset devices. The planar antenna structure is integrated with an L-shaped slot antenna. An inductor is placed on the slot to provide short-ended boundary and a capacitor is used to shorten the resonance length. To support MIMO uses, we arrange the two element antennas at corners of the system platform. The couplings between antennas are small due to radiation pattern diversity. Both element exhibit good radiation characteristics.In the second part, a metal body-integrated open-ended slot antenna design for LTE/WWAN uses on handsets is proposed. The slot is directly etched on the metal frame. The antenna composes three parts: LTE lower band antenna, LTE higher band antenna and feeding network. LTE lower band antenna is a quarter-wavelength slot covering the 698 ~ 960 GHz band. There is an internal metal strip in the LTE lower band slot, improves the impedance matching. The LTE higher band antenna is made with a dual open-ended slot that provides three resonance modes: They are two quarter-wavelength modes and one half-wavelength mode that cover the 1710 ~ 2690 GHz band. The feeding network is adopted to feed two slots with just one port. The feeding network contains not only a matching network but also a frequency divider. We can adjust the lumped element values to trade off matching condition and frequency divider condition. Through fabrication and measurement, good matching and radiation performance features are validated.The third part of this study proposes an LTE/WWAN linear dual open-ended slot antenna designs for handsets. It modifies the asymmetrical structure presented in the second part. A dual open-ended slot is etched on the metal frame and a metal piece is added in the slot. Hence, it functions as two open-ended slots. They can offer LTE lower and higher band operations, respectively. To support MIMO uses, the two element antennas are placed on the upper and lower edges of the metal frame. Measured isolation and diversity verify its superior performance.