volume | PIER Journals

Abstract

The proposed CP antenna element employs a microstrip feed and a 45° rectangular slot to excite two orthogonal modes with an approximately 90° phase difference, realizing circular polarization. Based on this element, a four-port CP MIMO antenna is constructed, and a 5 × 5 metasurface array (M-array) is integrated into the ground plane to suppress mutual coupling between adjacent antenna elements. The introduced M-array provides additional electromagnetic-wave control paths and suppresses surface-wave propagation between adjacent antenna elements, reducing mutual coupling and improving the radiation performance of the CP MIMO antenna. At 10.8 GHz, the dimensions of the CP MIMO antenna are 32 mm × 32 mm × 1.6 mm. Simulated results show that the CP MIMO antenna with the M-array offers a frequency range of 20.6% (10.5 to 12.7 GHz), an inter-port isolation exceeding 40 dB with a peak value of approximately 64 dB, a 4.7% overlapping 3 dB axial ratio bandwidth from 10.5 to 11 GHz, and a high gain of 9.75 dBi. Diversity metrics ensure good diversity performance, including an envelope correlation coefficient (ECC) below 0.001, a diversity gain (DG) of approximately 10 dB, a channel capacity loss (CCL) below 0.2 bits/Hz, and a total active reflection coefficient (TARC) below -10 dB. The proposed CP MIMO antenna operates over the 10.5-12.7 GHz frequency range, which spans the upper portion of the X-band and the lower portion of the Ku-band. The measured results show good agreement with the simulated ones, validating the proposed CP MIMO antenna for radar applications.

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Professor Jingchang Nan

Ms. Fengjun Liang

Dr. Shuming Liu