Low-Profile Open-Slot Antenna for the LTE Metal-Framed Tablet Computer

• Main Authors: Zih-Guang Liao, 廖子廣
• Other Authors: Kin-Lu Wong
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/7ke3h7

碩士 === 國立中山大學 === 電機工程學系研究所 === 103 === In this thesis, low-profile open-slot antennas applied to cover the LTE operation in the metal-framed tablet device are presented. The first antenna design is a low-profile (5 mm) LTE dual-feed open-slot antenna with active switches. In this design, the active switches are simplified as a conducting strip for the ON-state and an open circuit for the OFF-state. In the lower band, the inverted-L open slot is excited to generate the fundamental resonant mode by the first feed. In the higher band, the antenna is excited by the second feed to generate the 0.25-wavelength slot resonant mode created by the open-slot radiator formed between the slot opening and the microstrip feedline as a virtual shorting and the 0.5-wavelength slot resonant mode by the closed-slot radiator formed between the slot end and the microstrip feedline as a virtual shorting. By further adding wideband matching circuits in the first and second feeds, the antenna can achieve two wideband operations to cover the LTE bands. The second design is a U-shape open-slot (U-slot) antenna with a low profile of 6 mm for the LTE operation. The antenna can generate 0.5-wavelength and 1.0-wavelength slot resonant modes to cover the desired higher band. By using an inverted-U strip connecting across the U-slot, the antenna can create an additional open-slot radiator to generate a 0.25-wavelength slot resonant mode at lower frequencies. The desired lower wideband is then achieved by the antenna using a high-pass matching circuit.