Isolation enhancement of MIMO antennas using shorting pins

ABSTRACT

This paper provides an effective technique to reduce the mutual coupling between two adjacent probe-fed microstrip antenna elements operating at 3.5 GHz in multiple input multiple output (MIMO) configurations. The required reduction in the mutual coupling is achieved via loading of six metallic pins near the adjacent edges of two square patch radiators to ground the radiating elements in order to alter the polarization of the antennas. The two radiating elements are closely spaced with an edge-to-edge separation of 0.012λ_o and a centre-to-centre separation of 0.027λ_o. The idea is to make the two antennas orthogonal in terms of polarization via loading of shorting pins at appropriate locations. In order to validate the proposed technique, a two-element MIMO antenna is designed, fabricated, and measured. A good agreement between measurement and simulation is observed. Simulated and measured results are used to analyse the performance of the proposed technique in terms of mutual coupling between the two ports, radiation pattern, and realized peak gain. The measurement results show that the isolation between the two elements is enhanced from 2.8 dB to 20 dB at around 3.5 GHz.

KEYWORDS:

• Patch antennas
• MIMO
• mutual coupling
• polarization diversity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number 61801366]; State Key Laboratory of Millimetre Waves: [Grant Number K201933].

Notes on contributors

Muhammad Abdullah

Muhammad Abdullah received the B.S degree in Telecommunication Engineering from the University of Engineering and Technology Peshawar, Pakistan, in 2016. He is currently pursuing the M.S. degree in Information and Communication Engineering with Xi'an Jiaotong University China. He is also associated with Electromagnetics and Communication Laboratory at Xi’an Jiaotong University as a research scholar. His research interest includes antenna design for different applications.

Qinlong Li

Qinlong Li was born in Shanxi, China, in 1988. He received the B.S. degree from Xi’an Jiaotong University, Xi’an, China, in 2010, the M.S. degree from the University of Chinese Academy of Sciences, Beijing, China, in 2013, and the Ph.D. degree from the University of Hong Kong, Hong Kong, in 2018. He joined the electromagnetics and communication laboratory, Xi’an Jiaotong University, in 2019, as a lecturer. His current research interests include millimeter-wave antennas, base station antennas.

Wei Xue

Wei Xue received the B.S. and M.S. degrees from the Faculty of Electronics and Communication Engineering, Xi’an Jiaotong University, Xi’an, China, in 2011 and 2014, respectively. From 2014 to 2018, he was an avionic engineer in aeronautic computing technology institute, Xi’an, China. He is currently pursuing the Ph.D. degree in Electromagnetics and Communication Laboratory, Electronics and Communication Engineering, Xi'an Jiaotong University. His current research areas include reverberation chamber measurements and statistical electromagnetics.

Gantao Peng

Gantao Peng received the undergraduate degree in Electronics and Information Engineering from the Central China Normal University, Wuhan, in 2016. He is currently pursuing the M.S. degree in Electronics and Communication Engineering with Xi'an Jiaotong University, China. He is studying in Electromagnetics and Communication Laboratory and his research direction is the measurement technology of metamaterial's special properties.

Yifeng He

Yifeng He received the M.Sc. degree in electrical engineering from Xidian University, Xi’an, China, in 2010, and PhD degree in electrical engineering from Northwestern Polytechnical University, Xi’an, China, in 2019. He is a senior engineer of China Academy of Space Technology, engaged in research work in satellite communications.

Xiaoming Chen

Xiaoming Chen received the B.Sc. degree in electrical engineering from Northwestern Polytechnical University, Xi’an, China, in 2006, and M.Sc. and PhD degrees in electrical engineering from Chalmers University of Technology, Gothenburg, Sweden, in 2007 and 2012, respectively. From 2013 to 2014, he was a postdoctoral researcher at the same University. From 2014 to 2017, he was with Qamcom Research & Technology AB, Gothenburg, Sweden. Since 2017, he has been a professor at Xi’an Jiaotong University, Xi’an, China. His research areas include MIMO antennas, over-the-air (OTA) testing, reverberation chambers, and hardware impairments and mitigation. He serves as an Associate Editor (AE) for the journal of IEEE Antennas and Wireless Propagation Letters and received the outstanding AE award in 2018. He was also a Guest Editor of a Special Issue on “Metrology for 5G Technologies” in the journal of IET Microwaves, Antennas & Propagation. He received the URSI (International Union of Radio Science) Young Scientist Awards in 2017 and 2018.