Study of Wireless Mobile Communication Antennas

• Main Authors: Rong-kun Li, 李榮坤
• Other Authors: Wen-jiao Liao
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/24068417058390574819

碩士 === 國立臺灣科技大學 === 電機工程系 === 98 === This thesis proposed several types of miniaturized mobile phone antenna designs for commercial uses. The first design is a miniatured Wi-Fi/Wi-MAX (2.5~2.7, 3.4~3.7 GHz) chip antenna for mobile phone applications. This antenna does not require any empty space, which yields more space for system circuits. The second design is a WWAN/WLAN/Wi-MAX multi-band monopole antenna. We use multiple branches and parasitic element on the bottom layer to achieve multi-band operation and provide good radiation efficiency. The third antenna is a PIFA/IFA/Chip antenna arrangement with multi-band and spatial diversity features for smart phone applications. We use the spatial diversity technique to reduce multi-path fading and find the optimal displacement position for each antenna. In fourth research project, we integrate five antennas of DAB/DTV/WWAN/GPS/Wi-Fi applications into a mobile internet device. Among the five antennas, one is an active DAB antenna with improved reception capability. We also proposed two types of Wi-Fi/Wi-MAX dipole antennas for wireless access point applications. They not only satisfy WLAN 802.11 a/b/g band requirements, but also cover the communication bands of Wi-MAX (2.5~2.7, 3.4~3.7 GHz). For directive array antenna research, We proposed two types of beam switching array antenna. The first is a broadband yagi antenna system which combines a 1-to-4 RF switch to switch the beam toward four different directions on the azimuth plane. The second beam switching design composes a Butler Matrix and yagi antennas. A yagi antenna provides high gain and high front to back ratio. Through measurements, we verified that this combination can generate four directive switchable beams near the broadside direction. By applying the metamaterial, we developed a directive antenna at 5.8 GHz band. The patch antenna has a large L/W ratio of 5:1 and has a focusing substrate made of metamaterial placed on top of patch. The antenna gain can therefore enhanced further. This novel configuration, eliminate the need of a complicated feeding network required by phase array antennas. We also developed two array antennas of omni-directional coverage. The first is serially-connected folded dipole array antenna for Hyper LAN (5.15~5.85 GHz). The second antenna is an electronical beam switching array antenna in the UHF band. The antenna consists of 16 patch elements. It can achieve full azimuth coverage by selecting proper element antenna combinations.