A Bear-Shaped UWB MIMO Antenna Based on Characteristic Mode Analysis

Authors

  • Xiaoyan Wei School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China
  • Zhonggen Wang School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China
  • Wenyan Nie School of Mechanical and Electrical Engineering Huainan Normal University, Huainan 232001, China
  • Chenlu Li School of Electrical and Information Engineering Hefei Normal University, Hefei 230061, China
  • Zhengting Zhang School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China

DOI:

https://doi.org/10.13052/2026.ACES.J.410703

Keywords:

Characteristic mode theory, Defected ground structures, MIMO antenna, T-shaped feeder, ultra-wideband antenna

Abstract

This paper proposes a compact four-port ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with bear-shaped patches based on characteristic mode analysis (CMA). The antenna measures 62×62×1mm3, comprising orthogonally arranged bear-shaped radiating elements on the top layer, a cross-shaped hollowed-out decoupling structure on the bottom layer, and defected ground structures (DGS) with corner cuts and grooves at the four corners. Notably, the bear-shaped radiating elements are not just a morphological innovation; compared with traditional rectangular/circular elements, their irregular outline enriches equivalent current path diversity and increases excited resonant modes. Each antenna is optimized with etched slots, corner cuts and a T-shaped feeder, ensuring simultaneous excitation of five characteristic modes for UWB performance. For the MIMO configuration, mutual coupling is suppressed via orthogonal arrangement, the decoupling structure and DGS, with isolation over 20 dB. Simulations and measurements confirm the antenna operates in the 3.36–21.91 GHz band, featuring S11 < −10 dB and ECC < 0.005 across the band, a diversity gain approaching 9.9999 dB, 75–95% radiation efficiency, 7 dBi peak gain and a group delay less than 1 ns. This design outperforms existing designs in bandwidth, isolation and miniaturization, suited for advanced wireless communication scenarios requiring wide bandwidth, high isolation and a compact form factor.

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Author Biographies

Xiaoyan Wei, School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China

Xiaoyan Wei received the B.E. degree from Anhui University of Science and Technology, China, in 2024. She is currently pursuing the M.S. degree at Anhui University of Science and Technology. Her current research interests include the theory and design of UWB MIMO antenna based on characteristic mode analysis.

Zhonggen Wang, School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China

Zhonggen Wang received the Ph.D. degree in electromagnetic field and microwave technique from the Anhui University of China (AHU), Hefei, P. R. China, in 2014. Since 2014, he has been with the School of Electrical and Information Engineering, Anhui University of Science and Technology. His research interests include computational electromagnetics, array antennas, and reflect arrays.

Wenyan Nie, School of Mechanical and Electrical Engineering Huainan Normal University, Huainan 232001, China

Wenyan Nie is a professor at Huainan Normal University, China. She received the B.S. and M.S degrees from Anhui University of Science and Technology in 2007 and 2012, respectively. Her research interests include computational electromagnetic methods, antenna theory and design.

Chenlu Li, School of Electrical and Information Engineering Hefei Normal University, Hefei 230061, China

Chenlu Li received the Ph.D. degree from Anhui University, China, in 2017. She is currently working at Hefei Normal University. Her research interests include electromagnetic scattering analysis of targets and filtering antenna design.

Zhengting Zhang, School of Electrical and Information Engineering Anhui University of Science and Technology, Huainan 232001, China

Zhengting Zhang received the B.E. degree from Anhui University of Science and Technology, China, in 2024. He is currently pursuing the M.S degree at Anhui University of Science and Technology. His current research interests include the design and research of miniaturized antennas for 5G Sub-6 GHz applications.

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Published

2026-07-30

How to Cite

[1]
X. . Wei, Z. . Wang, W. . Nie, C. . Li, and Z. . Zhang, “A Bear-Shaped UWB MIMO Antenna Based on Characteristic Mode Analysis”, ACES Journal, vol. 41, no. 07, pp. 621–634, Jul. 2026.

Issue

2026: Vol 41 Iss 7

Section

General Submission

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