Low-profile switchable LTE/WWAN MIMO antenna system

ABSTRACT

This study proposes a low-profile switchable LTE/WWAN multi-input and multi-output (MIMO) antenna system for laptops. The main and auxiliary antennas, mirror-imaged of each other, are configured on the left and right sides of the top edge of the display ground plane. The two antennas are each a planar inverted-F antenna (PIFA) having the size of 102 × 5 × 3 mm³. The PIFA structure is matched in impedance with a set of reactive chip elements to increase the antenna operating bandwidth, and is combined with a set of switchable circuits to change the low-frequency resonant path in accordance with the switch status, ON or OFF, thus allowing the low-frequency modes to cover the LTE700 and GSM850/900 bands. Without any isolation element, an isolation of 15 dB or more can be achieved in the MIMO antenna system. The measured realized antenna efficiency is also 48% or greater.

KEYWORDS:

• Laptop antennas
• PIFA antennas
• MIMO LTE/WWAN antennas
• ECC (Envelope correlation coefficient)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Ministry of Science Technology, R.O.C. (in Taiwan): [Grant Number MOST 106-2622-E-606-001-CC3].

Notes on contributors

Shu-Chuan Chen

Shu-Chuan Chen received the B.S. and M.S. degrees in electrical engineering from National Defense University Chung Cheng Institute of Technology, Taoyuan, Taiwan, and the Ph.D. degree in electrical engineering from National Sun Yat-sen University, Kaohsiung, Taiwan, in 1998, 2004, and 2012, respectively. Since 2012 she has been an assistant professor in the department of electrical and electronic engineering, Chung Cheng Institute of Technology, National Defense University, (CCIT, NDU), Taoyuan, Taiwan, where she became an associate professor in 2016. She also holds over 20 patents, including U.S., Taiwan, and China patents. Her main research interests are in internal antennas for mobile communication devices.

Wun-Siang Cai

Wun-Siang Cai received the B.S. degree in communications engineering from Mingsin University of Science and Technology, Hsinchu, Taiwan, in 2015, and is currently pursuing the M.S degree in electrical engineering at National Yunlin University of Science and Technology, Yunlin, Taiwan.

Chung-I G. Hsu

Chung-I G. Hsu is a professor in electrical engineering at National Yunlin University of Science and Technology, Yunlin, Taiwan.

Meng-Kai Wu

Meng-Kai Wu is currently pursuing the M.S degree in electrical engineering at National Yunlin University of Science and Technology, Yunlin, Taiwan.