Electronically steerable antenna array for indoor positioning system

Abstract

This paper presents a 2.4 GHz electronically steerable antenna array (ESAA) using a phase shifter based on the 4×4 Butler matrix which is suitable for the wireless indoor positioning system (WIPS). The low cost and simplicity are advantages of the proposed ESAA. The main beam of the antenna can be steered at four positions in the elevation plane, from −37°, −12°, 12° to + 36° with the narrow beamwidth in order to increase localization accuracy and wide-angle coverage of 240° in the azimuth plane. The ESAA is demonstrated as a base station antenna in a single-anchor indoor localization system experimentation. Two indoor localization algorithms, including fingerprinting and direction-of-arrive (DoA), are implemented and discussed in this paper. The indoor measurement setups and localization results using the proposed ESAA are proven in this paper to have better results than other similar approaches.

Keywords:

• Butler matrix
• direction of arrival
• electronically steerable antenna
• smart antenna
• fingerprinting
• indoor localization
• indoor positioning
• received signal strength (RSS)

Acknowledgements

The authors would like to thank the reviewers for their constructive feedback of this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Hanoi University of Science and Technology [grant number T2017-PC-108].

Notes on contributors

Thi Duyen Bui

Thi Duyen Bui graduated in the field of Instrumentation and Industrial Informatics in 2004 and completed the master's degree in Control Engineering and Automation in 2007 at Hanoi University of Science and Technology. Since 2005, Thi Duyen Bui is working as a lecturer at the Faculty of Automation Technology, Electric Power University. At present, Thi Duyen Bui is a PhD student in Control and Automation Engineering, majoring in Measurement at Hanoi University of Science and Technology. Thi Duyen Bui's main research areas are antennas and high-frequency circuits, design of embedded systems for control and automation systems.

Minh Thuy Le

Minh Thuy Le received her engineer (2006) and MS (2008) degree in Electrical Engineering from Hanoi University of Science and Technology and PhD (2013) degree in Optical and Radio Frequency from Grenoble Institute of Technology, France. She is a lecturer and also a researcher at RF3I group of the Department of Instrumentation and Industrial Informatics (3I), School of Electrical Engineering (SEE), Hanoi University of Science and Technology (HUST), Vietnam. Her current interests include Embedded System, Wireless communication, RFID/DSRC, Indoor localization system, Metamaterials, Antenna, Phased array, Rectenna and Energy harvesting.

Quoc Cuong Nguyen

Quoc Cuong Nguyen received the engineer (1996) and MS (1998) degrees in Electrical Engineering from Hanoi University of Science and Technology (HUST), Vietnam, and PhD degree in Signal-Image-Speech-Telecoms from INP Grenoble (Institut National Polytechnique de Grenoble), France, in 2002. He is a lecturer/researcher at the Department of Instrumentation and Industrial Informatics – School of Electrical Engineering – HUST. His research interest concerns Signal Processing, Speech Recognition, Embedded Systems and RF communication.